Drugs Details

Drugs Info of Relenza
Drugs Details
  • Drugs Type  : FDA
  • Date : 9th Jul 2015 06:59 am
  • Brand Name : Relenza
  • Generic Name : zanamivir (Pronunciation: zan AM i vir)
Descriptions

The active component of RELENZA is zanamivir. The chemical name of zanamivir is 5- (acetylamino)-4-[(aminoiminomethyl)-amino]-2,6-anhydro-3,4,5-trideoxy-D-glycero-D-galactonon- 2-enonic acid. It has a molecular formula of C12H20N4O7 and a molecular weight of 332.3. It has the following structural formula:

 

RELENZA (zanamivir)  Structural Formula Illustration

 

Zanamivir is a white to off-white powder for oral inhalation with a solubility of approximately 18 mg/mL in water at 20°C.

RELENZA is for administration to the respiratory tract by oral inhalation only. Each RELENZA ROTADISK contains 4 regularly spaced double-foil blisters with each blister containing a powder mixture of 5 mg of zanamivir and 20 mg of lactose (which contains milk proteins). The contents of each blister are inhaled using a specially designed breath-activated plastic device for inhaling powder called the DISKHALER. After a RELENZA ROTADISK is loaded into the DISKHALER, a blister that contains medication is pierced and the zanamivir is dispersed into the air stream created when the patient inhales through the mouthpiece. The amount of drug delivered to the respiratory tract will depend on patient factors such as inspiratory flow. Under standardized in vitro testing, RELENZA ROTADISK delivers 4 mg of zanamivir from the DISKHALER device when tested at a pressure drop of 3 kPa (corresponding to a flow rate of about 62 to 65 L/min) for 3 seconds.

 

What are the possible side effects of zanamivir (Relenza)?

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Some people using zanamivir have had rare side effects of confusion, delirium and self-injury. These symptoms have occurred most often in children. It is not known whether zanamivir was the exact cause of these symptoms. However, anyone using zanamivir should be watched closely for signs of confusion or unusual behavior. Call a doctor at once if you or the child using zanamivir has any of these symptoms.

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What are the precautions when taking zanamivir (Relenza)?

Before using zanamivir, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients (such as lactose, milk proteins), which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: lung or breathing problems (such as asthma, chronic obstructive pulmonary disease-COPD).

This drug may make you dizzy. Do not drive, use machinery, or do any activity that requires alertness until you are sure you can perform such activities safely. Limit alcoholic beverages.

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Indications

Treatment of Influenza

RELENZA® (zanamivir) Inhalation Powder is indicated for treatment of uncomplicated acute illness due to influenza A and B virus in adults and pediatric patients aged 7 years and older who have been symptomatic for no more than 2 days.

Prophylaxis Of Influenza

RELENZA is indicated for prophylaxis of influenza in adults and pediatric patients aged 5 years and older.

Important Limitations On Use Of RELENZA

  • RELENZA is not recommended for treatment or prophylaxis of influenza in individuals with underlying airways disease (such as asthma orchronic obstructive pulmonary disease) due to risk of serious bronchospasm [see WARNINGS AND PRECAUTIONS].
  • RELENZA has not been proven effective for treatment of influenza in individuals with underlying airways disease.
  • RELENZA has not been proven effective for prophylaxis of influenza in the nursing home setting.
  • RELENZA is not a substitute for early influenza vaccination on an annual basis as recommended by the Centers for Disease Control'sImmunization Practices Advisory Committee.
  • Influenza viruses change over time. Emergence of resistance mutations could decrease drug effectiveness. Other factors (for example, changes in viral virulence) might also diminish clinical benefit of antiviral drugs. Prescribers should consider available information on influenza drug susceptibility patterns and treatment effects when deciding whether to use RELENZA.
  • There is no evidence for efficacy of zanamivir in any illness caused by agents other than influenza virus A and B.
  • Patients should be advised that the use of RELENZA for treatment of influenza has not been shown to reduce the risk of transmission of influenza to others.

Dosage Administration

Dosing Considerations

  • RELENZA is for administration to the respiratory tract by oral inhalation only, using the DISKHALER® device provided [see WARNINGS ANDPRECAUTIONS].
  • The 10-mg dose is provided by 2 inhalations (one 5-mg blister per inhalation).
  • Patients should be instructed in the use of the delivery system. Instructions should include a demonstration whenever possible. If RELENZA is prescribed for children, it should be used only under adult supervision and instruction, and the supervising adult should first be instructed by a healthcare professional [see PATIENT INFORMATION].
  • Patients scheduled to use an inhaled bronchodilator at the same time as RELENZA should use their bronchodilator before taking RELENZA [seePATIENT INFORMATION].

Treatment Of Influenza

  • The recommended dose of RELENZA for treatment of influenza in adults and pediatric patients aged 7 years and older is 10 mg twice daily (approximately 12 hours apart) for 5 days.
  • Two doses should be taken on the first day of treatment whenever possible provided there is at least 2 hours between doses.
  • On subsequent days, doses should be about 12 hours apart (e.g., morning and evening) at approximately the same time each day.
  • The safety and efficacy of repeated treatment courses have not been studied.

Prophylaxis Of Influenza

Household Setting
  • The recommended dose of RELENZA for prophylaxis of influenza in adults and pediatric patients aged 5 years and older in a household setting is 10 mg once daily for 10 days.
  • The dose should be administered at approximately the same time each day.
  • There are no data on the effectiveness of prophylaxis with RELENZA in a household setting when initiated more than 1.5 days after the onset of signs or symptoms in the index case.
Community Outbreaks
  • The recommended dose of RELENZA for prophylaxis of influenza in adults and adolescents  in a community setting is 10 mg once daily for 28 days.
  • The dose should be administered at approximately the same time each day.
  • There are no data on the effectiveness of prophylaxis with RELENZA in a community outbreak when initiated more than 5 days after the outbreak was identified in the community.
  • The safety and effectiveness of prophylaxis with RELENZA have not been evaluated for longer than 28 days' duration.

How Supplied

Dosage Forms And Strengths

Blister for oral inhalation: 5 mg. Four 5-mg blisters of powder on a ROTADISK® for oral inhalation via DISKHALER. Packaged in carton containing 5 ROTADISKs (total of 10 doses) and 1 DISKHALER inhalation device [see Storage and Handling].

Storage And Handling

RELENZA is supplied in a circular double-foil pack (a ROTADISK) containing 4 blisters of the drug. Five ROTADISKs are packaged in a white polypropylene tube. The tube is packaged in a carton with 1 blue and gray DISKHALER inhalation device (NDC 0173-0681-01).

Store at 25°C (77°F); excursions permitted to 15° to 30°C (59° to 86°F) (see USP Controlled Room Temperature). Keep out of reach of children. Do not puncture any RELENZA ROTADISK blister until taking a dose using the DISKHALER.

GlaxoSmithKline: Research Triangle Park, NC 27709. Revised: October 2013

Side Effects

See WARNINGS AND PRECAUTIONS for information about risk of serious adverse events such as bronchospasm and allergic-like reactions, and for safety information in patients with underlying airways disease.

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared with rates in the clinical trials of another drug and may not reflect the rates observed in practice.

The placebo used in clinical trials consisted of inhaled lactose powder, which is also the vehicle for the active drug; therefore, some adverse events occurring at similar frequencies in different treatment groups could be related to lactose vehicle inhalation.

Treatment of Influenza

Clinical Trials in Adults and Adolescents: Adverse events that occurred with an incidence ≥ 1.5% in treatment trials are listed in Table 1. This table shows adverse events occurring in subjects aged 12 years and older receiving RELENZA 10 mg inhaled twice daily, RELENZA in all inhalation regimens, and placebo inhaled twice daily (where placebo consisted of the same lactose vehicle used in RELENZA).

Table 1: Summary of Adverse Events ≥ 1.5% Incidence During Treatment in Adults and Adolescents

ADVERSE EVENT RELENZA PLACEBO (LACTOSE VEHICLE)
(N = 1,520)
10 MG B.I.D. INHALED
(N = 1,132)
ALL DOSING REGIMENSA 
(N = 2,289)
Body as a whole
  Headaches 2% 2% 3%
Digestive
  Diarrhea 3% 3% 4%
  Nausea 3% 3% 3%
  Vomiting 1% 1% 2%
Respiratory
  Nasal signs and symptoms 2% 3% 3%
  Bronchitis 2% 2% 3%
  Cough 2% 2% 3%
  Sinusitis 3% 2% 2%
  Ear, nose, and throat infections 2% 1% 2%
Nervous system
  Dizziness 2% 1% < 1%
a Includes trials where RELENZA was administered intranasally (6.4 mg 2 to 4 times per day in addition to inhaled preparation) and/or inhaled more frequently (q.i.d.) than the currently recommended dose.

 

Additional adverse reactions occurring in less than 1.5% of subjects receiving RELENZA included malaise, fatigue, fever, abdominal pain, myalgia,arthralgia, and urticaria.

The most frequent laboratory abnormalities in Phase III treatment trials included elevations of liver enzymes and CPK, lymphopenia, andneutropenia. These were reported in similar proportions of zanamivir and lactose vehicle placebo recipients with acute influenza-like illness.

Clinical Trials in Pediatric Subjects: Adverse events that occurred with an incidence ≥ 1.5% in children receiving treatment doses of RELENZA in 2 Phase III trials are listed in Table 2. This table shows adverse events occurring in pediatric subjects aged 5 to 12 years receiving RELENZA 10 mg inhaled twice daily and placebo inhaled twice daily (where placebo consisted of the same lactose vehicle used in RELENZA).

Table 2: Summary of Adverse Events ≥ 1.5% Incidence During Treatment in Pediatric Subjectsa

ADVERSE EVENT RELENZA 10 MG B.I.D. INHALED 
(N = 291)
PLACEBO (LACTOSE VEHICLE)
(N = 318)
Respiratory
  Ear, nose, and throat infections 5% 5%
  Ear, nose, and throat hemorrhage < 1% 2%
  Asthma < 1% 2%
  Cough < 1% 2%
Digestive
  Vomiting 2% 3%
  Diarrhea 2% 2%
  Nausea < 1% 2%
a Includes a subset of subjects receiving RELENZA for treatment of influenza in a prophylaxis trial.

 

In 1 of the 2 trials described in Table 2, some additional information is available from children (aged 5 to 12 years) without acute influenza-like illness who received an investigational prophylaxis regimen of RELENZA; 132 children received RELENZA and 145 children received placebo. Among these children, nasal signs and symptoms (zanamivir 20%, placebo 9%), cough (zanamivir 16%, placebo 8%), and throat/tonsil discomfort and pain (zanamivir 11%, placebo 6%) were reported more frequently with RELENZA than placebo. In a subset with chronic pulmonary disease, lower respiratory adverse events (described as asthma, cough, or viral respiratory infections which could include influenza-like symptoms) were reported in 7 of 7 zanamivir recipients and 5 of 12 placebo recipients.

Prophylaxis of Influenza

Family/Household Prophylaxis Studies: Adverse events that occurred with an incidence of ≥ 1.5% in the 2 prophylaxis trials are listed in Table 3. This table shows adverse events occurring in subjects aged 5 years and older receiving RELENZA 10 mg inhaled once daily for 10 days.

Table 3: Summary of Adverse Events ≥ 1.5% Incidence During 10-Day Prophylaxis Trials in Adults, Adolescents, and Childrena

ADVERSE EVENT CONTACT CASES
RELENZA
(N = 1,068)
PLACEBO
(N = 1,059)
Lower respiratory
  Viral respiratory infections 13% 19%
  Cough 7% 9%
Neurologic
  Headaches 13% 14%
Ear, nose, and throat
  Nasal signs and symptoms 12% 12%
  Throat and tonsil discomfort and pain 8% 9%
  Nasal inflammation 1% 2%
Musculoskeletal
  Muscle pain 3% 3%
Endocrine and metabolic
  Feeding problems (decreased or increased appetite and anorexia) 2% 2%
Gastrointestinal
  Nausea and vomiting 1% 2%
Non-site specific
  Malaise and fatigue 5% 5%
  Temperature regulation disturbances (fever and/or chills) 5% 4%
a In prophylaxis trials, symptoms associated with influenza-like illness were captured as adverse events; subjects were enrolled during a winter respiratory season during which time any symptoms that occurred were captured as adverse events.

 

Community Prophylaxis Trials: Adverse events that occurred with an incidence of ≥ 1.5% in 2 prophylaxis trials are listed in Table 4. This table shows adverse events occurring in subjects aged 5 years and older receiving RELENZA 10 mg inhaled once daily for 28 days.

Table 4: Summary of Adverse Events ≥ 1.5% Incidence During 28-Day Prophylaxis Trials in Adults, Adolescents, and Childrena

ADVERSE EVENT RELENZA
(N = 2,231)
PLACEBO
(N = 2,239)
Neurologic
  Headaches 24% 26%
Ear, nose, and throat
  Throat and tonsil discomfort and pain 19% 20%
  Nasal signs and symptoms 12% 13%
  Ear, nose, and throat infections 2% 2%
Lower respiratory
  Cough 17% 18%
  Viral respiratory infections 3% 4%
Musculoskeletal
  Muscle pain 8% 8%
  Musculoskeletal pain 6% 6%
  Arthralgia and articular rheumatism 2% < 1%
Endocrine and metabolic
  Feeding problems (decreased or increased appetite and anorexia) 4% 4%
Gastrointestinal
  Nausea and vomiting 2% 3%
  Diarrhea 2% 2%
Non-site specific
  Temperature regulation disturbances (fever and/or chills) 9% 10%
  Malaise and fatigue 8% 8%
a In prophylaxis trials, symptoms associated with influenza-like illness were captured as adverse events; subjects were enrolled during a winter respiratory season during which time any symptoms that occurred were captured as adverse events.

 

Postmarketing Experience

In addition to adverse events reported from clinical trials, the following events have been identified during postmarketing use of zanamivir (RELENZA). Because they are reported voluntarily from a population of unknown size, estimates of frequency cannot be made. These events have been chosen for inclusion due to a combination of their seriousness, frequency of reporting, or potential causal connection to zanamivir (RELENZA).

Allergic Reactions: Allergic or allergic-like reaction, including oropharyngeal edema [see WARNINGS AND PRECAUTIONS].

Psychiatric: Delirium, including symptoms such as altered level of consciousness, confusion, abnormal behavior, delusions, hallucinations, agitation, anxiety, nightmares [see WARNINGS AND PRECAUTIONS].

Cardiac: Arrhythmias, syncope.

Neurologic: Seizures. Vasovagal-like episodes have been reported shortly following inhalation of zanamivir.

Respiratory: Bronchospasm, dyspnea [see WARNINGS ANDPRECAUTIONS].

Skin: Facial edema; rash, including serious cutaneous reactions (e.g.,erythema multiforme, Stevens-Johnson syndrome, toxic epidermalnecrolysis); urticaria [see WARNINGS AND PRECAUTIONS].

Interactions

Zanamivir is not a substrate nor does it affect cytochrome P450 (CYP) isoenzymes (CYP1A1/2, 2A6, 2C9, 2C18, 2D6, 2E1, and 3A4) in human liver microsomes. No clinically significant pharmacokinetic drug interactions are predicted based on data from in vitro studies.

The concurrent use of RELENZA with live attenuated influenza vaccine (LAIV) intranasal has not been evaluated. However, because of potential interference between these products, LAIV should not be administered within 2 weeks before or 48 hours after administration of RELENZA, unless medically indicated. The concern about possible interference arises from the potential for antiviral drugs to inhibit replication of live vaccine virus.

Trivalent inactivated influenza vaccine can be administered at any time relative to use of RELENZA [see CLINICAL PHARMACOLOGY].

Warnings

Included as part of the PRECAUTIONS section.

Precautions

Bronchospasm

RELENZA is not recommended for treatment or prophylaxis of influenza in individuals with underlying airways disease (such as asthma or chronic obstructive pulmonary disease).

Serious cases of bronchospasm, including fatalities, have been reported during treatment with RELENZA in patients with and without underlying airways disease. Many of these cases were reported during postmarketing and causality was difficult to assess.

RELENZA should be discontinued in any patient who develops bronchospasm or decline in respiratory function; immediate treatment and hospitalization may be required.

Some patients without prior pulmonary disease may also have respiratory abnormalities from acute respiratory infection that could resemble adverse drug reactions or increase patient vulnerability to adverse drug reactions.

Bronchospasm was documented following administration of zanamivir in 1 of 13 subjects with mild or moderate asthma (but without acute influenza-like illness) in a Phase I trial. In a Phase III trial in subjects with acute influenza-like illness superimposed on underlying asthma or chronic obstructive pulmonary disease, 10% (24 of 244) of subjects on zanamivir and 9% (22 of 237) on placebo experienced a greater than 20% decline in FEV1 following treatment for 5 days.

If use of RELENZA is considered for a patient with underlying airways disease, the potential risks and benefits should be carefully weighed. If a decision is made to prescribe RELENZA for such a patient, this should be done only under conditions of careful monitoring of respiratory function, close observation, and appropriate supportive care including availability of fast-acting bronchodilators.

Allergic Reactions

Allergic-like reactions, including oropharyngeal edema, serious skin rashes, and anaphylaxis have been reported in postmarketing experience with RELENZA. RELENZA should be stopped and appropriate treatment instituted if an allergic reaction occurs or is suspected.

Neuropsychiatric Events

Influenza can be associated with a variety of neurologic and behavioral symptoms which can include events such as seizures, hallucinations,delirium, and abnormal behavior, in some cases resulting in fatal outcomes. These events may occur in the setting of encephalitis or encephalopathy but can occur without obvious severe disease.

There have been postmarketing reports (mostly from Japan) of delirium and abnormal behavior leading to injury in patients with influenza who were receiving neuraminidase inhibitors, including RELENZA. Because these events were reported voluntarily during clinical practice, estimates of frequency cannot be made, but they appear to be uncommon based on usage data for RELENZA. These events were reported primarily among pediatric patients and often had an abrupt onset and rapid resolution. The contribution of RELENZA to these events has not been established. Patients with influenza should be closely monitored for signs of abnormal behavior. If neuropsychiatric symptoms occur, the risks and benefits of continuing treatment should be evaluated for each patient.

Limitations Of Populations Studied

Safety and efficacy have not been demonstrated in patients with high-risk underlying medical conditions. No information is available regarding treatment of influenza in patients with any medical condition sufficiently severe or unstable to be considered at imminent risk of requiring inpatientmanagement.

Bacterial Infections

Serious bacterial infections may begin with influenza-like symptoms or may coexist with or occur as complications during the course of influenza. RELENZA has not been shown to prevent such complications.

Importance Of Proper Route Of Administration

RELENZA Inhalation Powder must not be made into an extemporaneous solution for administration by nebulization or mechanical ventilation. There have been reports of hospitalized patients with influenza who received a solution made with RELENZA Inhalation Powder administered by nebulization or mechanical ventilation, including a fatal case where it was reported that the lactose in this formulation obstructed the proper functioning of the equipment. RELENZA Inhalation Powder must only be administered using the device provided [see DOSAGE AND ADMINISTRATION].

Importance Of Proper Use Of DISKHALER

Effective and safe use of RELENZA requires proper use of the DISKHALER to inhale the drug. Prescribers should carefully evaluate the ability of young children to use the delivery system if use of RELENZA is considered [seeUse in Specific Populations].

Patient Counseling Information

See FDA-approved patient labeling (PATIENT INFORMATION and Instructions for Use).

Bronchospasm

Inform patients of the risk of bronchospasm, especially in the setting of underlying airways disease, and advise patients to stop RELENZA and contact their healthcare provider if they experience increased respiratory symptoms during treatment such as worsening wheezing, shortness of breath, or other signs or symptoms of bronchospasm [see WARNINGS AND PRECAUTIONS]. If a decision is made to prescribe RELENZA for a patient with asthma or chronic obstructive pulmonary disease, the patient should be made aware of the risks and should have a fast-acting bronchodilator available.

Concomitant Bronchodilator Use

Patients scheduled to take inhaled bronchodilators at the same time as RELENZA should be advised to use their bronchodilators before taking RELENZA.

Neuropsychiatric Events

Inform patients with influenza (the flu), particularly children and adolescents, they may be at an increased risk of seizures, confusion, or abnormal behavior early in their illness. These events may occur after beginning RELENZA or may occur when flu is not treated. These events are uncommon but may result in accidental injury to the patient. Therefore, patients should be observed for signs of unusual behavior and a healthcare professional should be contacted immediately if the patient shows any signs of unusual behavior [see WARNINGS AND PRECAUTIONS].

Instructions for Use

Instruct patients in use of the delivery system. Instructions should include a demonstration whenever possible. For the proper use of RELENZA, the patient should read and follow carefully the accompanying Instructions for Use.

If RELENZA is prescribed for children, it should be used only under adult supervision and instruction, and the supervising adult should first be instructed by a healthcare professional [see DOSAGE AND ADMINISTRATION].

Risk of Influenza Transmission to Others

Inform patients that the use of RELENZA for treatment of influenza has not been shown to reduce the risk of transmission of influenza to others.

Nonclinical Toxicology

Carcinogenesis, Mutagenesis, Impairment Of Fertility

Carcinogenesis

In 2-year carcinogenicity studies conducted in rats and mice using a powder formulation administered through inhalation, zanamivir induced no statistically significant increases in tumors over controls. The maximum daily exposures in rats and mice were approximately 23 to 25 and 20 to 22 times, respectively, greater than those in humans at the proposed clinical dose based on AUC comparisons.

Mutagenesis

Zanamivir was not mutagenic in in vitro and in vivo genotoxicity assays which included bacterial mutation assays in S. typhimurium and E. coli, mammalian mutation assays in mouse lymphoma, chromosomal aberration assays in human peripheral blood lymphocytes, and the in vivo mouse bone marrowmicronucleus assay.

Impairment of Fertility

The effects of zanamivir on fertility and general reproductive performance were investigated in male (dosed for 10 weeks prior to mating, and throughout mating, gestation/lactation, and shortly after weaning) and female rats (dosed for 3 weeks prior to mating through Day 19 of pregnancy, or Day 21 post partum) at IV doses 1, 9, and 90 mg/kg/day. Zanamivir did not impair mating or fertility of male or female rats, and did not affect the sperm of treated male rats. The reproductive performance of the F1 generation born to female rats given zanamivir was not affected. Based on a subchronic study in rats at a 90 mg/kg/day IV dose, AUC values ranged between 142 and 199 mcg•h/mL ( > 300 times the human exposure at the proposed clinical dose).

Use In Specific Populations

Pregnancy

Pregnancy Category C

There are no adequate and well-controlled studies of zanamivir in pregnant women. Zanamivir should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Embryo/fetal development studies were conducted in rats (dosed from days 6 to 15 of pregnancy) and rabbits (dosed from days 7 to 19 of pregnancy) using the same IV doses (1, 9, and 90 mg/kg/day). Pre- and post-natal developmental studies were performed in rats (dosed from day 16 of pregnancy until litter day 21 to 23). No malformations, maternal toxicity, or embryotoxicity were observed in pregnant rats or rabbits and their fetuses. Because of insufficient blood sampling timepoints in rat and rabbit reproductive toxicity studies, AUC values were not available. In a subchronic study in rats at the 90 mg/kg/day IV dose, the AUC values were greater than 300 times the human exposure at the proposed clinical dose.

An additional embryo/fetal study, in a different strain of rat, was conducted using subcutaneous administration of zanamivir, 3 times daily, at doses of 1, 9, or 80 mg/kg during days 7 to 17 of pregnancy. There was an increase in the incidence rates of a variety of minor skeleton alterations and variants in the exposed offspring in this study. Based on AUC measurements, the 80-mg/kg dose produced an exposure greater than 1,000 times the human exposure at the proposed clinical dose. However, in most instances, the individual incidence rate of each skeletal alteration or variant remained within the background rates of the historical occurrence in the strain studied.

Zanamivir has been shown to cross the placenta in rats and rabbits. In these animals, fetal blood concentrations of zanamivir were significantly lower than zanamivir concentrations in the maternal blood.

Nursing Mothers

Studies in rats have demonstrated that zanamivir is excreted in milk. However, nursing mothers should be instructed that it is not known whether zanamivir is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when RELENZA is administered to a nursing mother.

Pediatric Use

Treatment of Influenza

Safety and effectiveness of RELENZA for treatment of influenza have not been assessed in pediatric patients younger than 7 years, but were studied in a Phase III treatment trial in pediatric subjects, where 471 children aged 5 to 12 years received zanamivir or placebo [see Clinical Studies]. Adolescents were included in the 3 principal Phase III adult treatment trials. In these trials, 67 patients were aged 12 to 16 years. No definite differences in safety and efficacy were observed between these adolescent patients and young adults.

In a Phase I trial of 16 children aged 6 to 12 years with signs and symptoms of respiratory disease, 4 did not produce a measurable peak inspiratory flow rate (PIFR) through the DISKHALER (3 with no adequate inhalation on request, 1 with missing data), 9 had measurable PIFR on each of 2 inhalations, and 3 achieved measurable PIFR on only 1 of 2 inhalations. Neither of two 6-year-olds and one of two 7-year-olds produced measurable PIFR. Overall, 8 of the 16 children (including all those younger than 8 years) either did not produce measurable inspiratory flow through the DISKHALER or produced peak inspiratory flow rates below the 60 L/min considered optimal for the device under standardized in vitro testing; lack of measurable flow rate was related to low or undetectable serum concentrations [seeCLINICAL PHARMACOLOGY, Clinical Studies]. Prescribers should carefully evaluate the ability of young children to use the delivery system if prescription of RELENZA is considered.

Prophylaxis of Influenza

The safety and effectiveness of RELENZA for prophylaxis of influenza have been studied in 4 Phase III trials where 273 children aged 5 to 11 years and 239 adolescents aged 12 to 16 years received RELENZA. No differences in safety and effectiveness were observed between pediatric and adult subjects [see Clinical Studies].

Geriatric Use

Of the total number of subjects in 6 clinical trials of RELENZA for treatment of influenza, 59 subjects were aged 65 years and older, while 24 subjects were aged 75 years and older. Of the total number of subjects in 4 clinical trials of RELENZA for prophylaxis of influenza in households and community settings, 954 subjects were aged 65 years and older, while 347 subjects were aged 75 years and older. No overall differences in safety or effectiveness were observed between these subjects and younger subjects, and other reported clinical experience has not identified differences in responses between the elderly and younger subjects, but greater sensitivity of some older individuals cannot be ruled out. Elderly patients may need assistance with use of the device.

In 2 additional trials of RELENZA for prophylaxis of influenza in the nursing home setting, efficacy was not demonstrated [see INDICATIONS].

OverDose

There have been no reports of overdosage from administration of RELENZA.

ContrainDications

Do not use in patients with history of allergic reaction to any ingredient of RELENZA including milk proteins [see WARNINGS AND PRECAUTIONS,DESCRIPTION].

Clinical Pharamacology

Mechanism Of Action

Zanamivir is an antiviral drug [see Microbiology].

Pharmacokinetics

Absorption and Bioavailability

Pharmacokinetic studies of orally inhaled zanamivir indicate that approximately 4% to 17% of the inhaled dose is systemically absorbed. The peak serum concentrations ranged from 17 to 142 ng/mL within 1 to 2 hours following a 10-mg dose. The area under the serum concentration versus time curve (AUC∞) ranged from 111 to 1,364 ng•h/mL.

Distribution

Zanamivir has limited plasma protein binding ( < 10%).

Metabolism

Zanamivir is renally excreted as unchanged drug. No metabolites have been detected in humans.

Elimination

The serum half-life of zanamivir following administration by oral inhalation ranges from 2.5 to 5.1 hours. It is excreted unchanged in the urine with excretion of a single dose completed within 24 hours. Total clearance ranges from 2.5 to 10.9 L/h. Unabsorbed drug is excreted in the feces.

Impaired Hepatic Function

The pharmacokinetics of zanamivir have not been studied in patients with impaired hepatic function.

Impaired Renal Function

After a single intravenous dose of 4 mg or 2 mg of zanamivir in volunteers with mild/moderate or severe renal impairment, respectively, significant decreases in renal clearance (and hence total clearance: normals 5.3 L/h, mild/moderate 2.7 L/h, and severe 0.8 L/h; median values) and significant increases in half-life (normals 3.1 h, mild/moderate 4.7 h, and severe 18.5 h; median values) and systemic exposure were observed. Safety and efficacy have not been documented in the presence of severe renal insufficiency. Due to the low systemic bioavailability of zanamivir following oral inhalation, no dosage adjustments are necessary in patients with renal impairment. However, the potential for drug accumulation should be considered.

Pediatric Patients

The pharmacokinetics of zanamivir were evaluated in pediatric subjects with signs and symptoms of respiratory illness. Sixteen subjects, aged 6 to 12 years, received a single dose of 10 mg zanamivir dry powder via DISKHALER. Five subjects had either undetectable zanamivir serum concentrations or had low drug concentrations (8.32 to 10.38 ng/mL) that were not detectable after 1.5 hours. Eleven subjects had Cmax median values of 43 ng/mL (range: 15 to 74) and AUC∞ median values of 167 ng•h/mL (range: 58 to 279). Low or undetectable serum concentrations were related to lack of measurable PIFR in individual subjects [see Use In Specific Populations, Clinical Studies].

Geriatric Patients

The pharmacokinetics of zanamivir have not been studied in subjects older than 65 years [see Use In Specific Populations].

Gender, Race, and Weight

In a population pharmacokinetic analysis in patient trials, no clinically significant differences in serum concentrations and/or pharmacokinetic parameters (V/F, CL/F, ka, AUC0-3, Cmax, Tmax, CLr, and % excreted in urine) were observed when demographic variables (gender, age, race, and weight) and indices of infection (laboratory evidence of infection, overall symptoms, symptoms of upper respiratory illness, and viral titers) were considered. There were no significant correlations between measures of systemic exposure and safety parameters.

Microbiology

Mechanism of Action

Zanamivir is an inhibitor of influenza virus neuraminidase affecting release of viral particles.

Antiviral Activity

The antiviral activity of zanamivir against laboratory and clinical isolates of influenza virus was determined in cell culture assays. The concentrations of zanamivir required for inhibition of influenza virus were highly variable depending on the assay method used and virus isolate tested. The 50% and 90% effective concentrations (EC50 and EC90) of zanamivir were in the range of 0.005 to 16.0 μM and 0.05 to > 100 μM, respectively (1 μM = 0.33 mcg/mL). The relationship between the cell culture inhibition of influenza virus by zanamivir and the inhibition of influenza virus replication in humans has not been established.

Resistance

Influenza viruses with reduced susceptibility to zanamivir have been selected in cell culture by multiple passages of the virus in the presence of increasing concentrations of the drug. Genetic analysis of these viruses showed that the reduced susceptibility in cell culture to zanamivir is associated with mutations that result in amino acid changes in the viral neuraminidase or viral hemagglutinin or both. Resistance mutations selected in cell culture which result in neuraminidase amino acid substitutions include E119G/A/D and R292K. Mutations selected in cell culture in hemagglutinin include: K68R, G75E, E114K, N145S, S165N, S186F, N199S, and K222T.

In an immunocompromised patient infected with influenza B virus, a variant virus emerged after treatment with an investigational nebulized solution of zanamivir for 2 weeks. Analysis of this variant showed a hemagglutinin substitution (T198I) which resulted in a reduced affinity for human cell receptors, and a substitution in the neuraminidase active site (R152K) which reduced the enzyme's activity to zanamivir by 1,000-fold. Insufficient information is available to characterize the risk of emergence of zanamivir resistance in clinical use.

Cross-Resistance

Cross-resistance has been observed between some zanamivir-resistant and some oseltamivir-resistant influenza virus mutants generated in cell culture. However, some of the in cell culture zanamivir-induced resistance mutations, E119G/A/D and R292K, occurred at the same neuraminidase amino acid positions as in the clinical isolates resistant to oseltamivir, E119V and R292K. No trials have been performed to assess risk of emergence of cross-resistance during clinical use.

Influenza Vaccine Interaction Trial

An interaction trial (n = 138) was conducted to evaluate the effects of zanamivir (10 mg once daily) on the serological response to a single dose of trivalent inactivated influenza vaccine, as measured by hemagglutination inhibition titers. There was no difference in hemagglutination inhibition antibody titers at 2 weeks and 4 weeks after vaccine administration between zanamivir and placebo recipients.

Influenza Challenge Trials

Antiviral activity of zanamivir was supported for infection with influenza A virus, and to a more limited extent for infection with influenza B virus, by Phase I trials in volunteers who received intranasal inoculations of challenge strains of influenza virus, and received an intranasal formulation of zanamivir or placebo starting before or shortly after viral inoculation.

Clinical Studies

Treatment Of Influenza

Adults and Adolescents

The efficacy of RELENZA 10 mg inhaled twice daily for 5 days in the treatment of influenza has been evaluated in placebo-controlled trials conducted in North America, the Southern Hemisphere, and Europe during their respective influenza seasons. The magnitude of treatment effect varied between trials, with possible relationships to population-related factors including amount of symptomatic relief medication used.

Populations Studied

The principal Phase III trials enrolled 1,588 subjects aged 12 years and older (median age 34 years, 49% male, 91% Caucasian), with uncomplicated influenza-like illness within 2 days of symptom onset. Influenza was confirmed by culture, hemagglutination inhibition antibodies, or investigational direct tests. Of 1,164 subjects with confirmed influenza, 89% had influenza A and 11% had influenza B. These trials served as the principal basis for efficacy evaluation, with more limited Phase II studies providing supporting information where necessary. Following randomization to either zanamivir or placebo (inhaled lactose vehicle), all subjects received instruction and supervision by a healthcare professional for the initial dose.

Principal Results: The definition of time to improvement in major symptoms of influenza included no fever and self-assessment of “none” or “mild” for headache, myalgia, cough, and sore throat. A Phase II and a Phase III trial conducted in North America (total of over 600 influenza-positive subjects) suggested up to 1 day of shortening of median time to this defined improvement in symptoms in subjects receiving zanamivir compared with placebo, although statistical significance was not reached in either of these trials. In a trial conducted in the Southern Hemisphere (321 influenza-positive subjects), a 1.5-day difference in median time to symptom improvement was observed. Additional evidence of efficacy was provided by the  European trial.

Other Findings

There was no consistent difference in treatment effect in subjects with influenza A compared with influenza B; however, these trials enrolled smaller numbers of subjects with influenza B and thus provided less evidence in support of efficacy in influenza B.

In general, subjects with lower temperature (e.g., 38.2°C or less) or investigator-rated as having less severe symptoms at entry derived less benefit from therapy.

No consistent treatment effect was demonstrated in subjects with underlying chronic medical conditions, including respiratory or cardiovascular disease[see WARNINGS AND PRECAUTIONS].

No consistent differences in rate of development of complications were observed between treatment groups.

Some fluctuation of symptoms was observed after the primary trial endpoint in both treatment groups.

Pediatric Patients

The efficacy of RELENZA 10 mg inhaled twice daily for 5 days in the treatment of influenza in pediatric patients has been evaluated in a placebo-controlled trial conducted in North America and Europe, enrolling 471 subjects, aged 5 to 12 years (55% male, 90% Caucasian), within 36 hours of symptom onset. Of 346 subjects with confirmed influenza, 65% had influenza A and 35% had influenza B. The definition of time to improvement included no fever and parental assessment of no or mild cough and absent/minimal muscle and joint aches or pains, sore throat, chills/feverishness, and headache. Median time to symptom improvement was 1 day shorter in subjects receiving zanamivir compared with placebo. No consistent differences in rate of development of complications were observed between treatment groups. Some fluctuation of symptoms was observed after the primary trial endpoint in both treatment groups.

Although this trial was designed to enroll children aged 5 to 12 years, the product is indicated only for children aged 7 years and older. This evaluation is based on the combination of lower estimates of treatment effect in 5- and 6-year-olds compared with the overall trial population, and evidence of inadequate inhalation through the DISKHALER in a pharmacokinetic trial [seeUse In Specific Populations, Pharmacokinetics].

Prophylaxis Of Influenza

The efficacy of RELENZA in preventing naturally occurring influenza illness has been demonstrated in 2 post-exposure prophylaxis trials in households and 2 seasonal prophylaxis trials during community outbreaks of influenza. The primary efficacy endpoint in these trials was the incidence of symptomatic, laboratory-confirmed influenza, defined as the presence of 2 or more of the following symptoms: oral temperature ≥ 100°F/37.8°C or feverishness, cough, headache, sore throat, and myalgia; and laboratory confirmation of influenza A or B by culture, PCR, or seroconversion (defined as a 4-fold increase in convalescent antibody titer from baseline).

Household Prophylaxis Trials

Two trials assessed post-exposure prophylaxis in household contacts of anindex case. Within 1.5 days of onset of symptoms in an index case, each household (including all family members aged 5 years and older) was randomized to RELENZA 10 mg inhaled once daily or placebo inhaled once daily for 10 days. In the first trial only, each index case was randomized to RELENZA 10 mg inhaled twice daily for 5 days or inhaled placebo twice daily for 5 days. In this trial, the proportion of households with at least 1 new case of symptomatic laboratory-confirmed influenza was reduced from 19.0% (32 of 168 households) for the placebo group to 4.1% (7 of 169 households) for the group receiving RELENZA.

In the second trial, index cases were not treated. The incidence of symptomatic laboratory-confirmed influenza was reduced from 19.0% (46 of 242 households) for the placebo group to 4.1% (10 of 245 households) for the group receiving RELENZA.

Seasonal Prophylaxis Trials

Two seasonal prophylaxis trials assessed RELENZA 10 mg inhaled once daily versus placebo inhaled once daily for 28 days during community outbreaks. The first trial enrolled subjects aged 18 years or older (mean age: 29 years) from 2 university communities. The majority of subjects were unvaccinated (86%). In this trial, the incidence of symptomatic laboratory-confirmed influenza was reduced from 6.1% (34 of 554) for the placebo group to 2.0% (11 of 553) for the group receiving RELENZA.

The second seasonal prophylaxis trial enrolled subjects aged 12 to 94 years (mean age: 60 years) with 56% of them older than 65 years. Sixty-seven percent of the subjects were vaccinated. In this trial, the incidence of symptomatic laboratory-confirmed influenza was  reduced from 1.4% (23 of 1,685) for the placebo group to 0.2% (4 of 1,678) for the group receiving RELENZA.

Patient Information

No information provided. Please refer to the WARNINGS ANDPRECAUTIONS section.

Consumer Overview Uses

IMPORTANT: HOW TO USE THIS INFORMATION: This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.

 

ZANAMIVIR INHALER - ORAL

 

(za-NAM-i-vir)

 

COMMON BRAND NAME(S): Relenza

 

USES: Zanamivir is used to treat symptoms caused by the flu virus (influenza) if you have had symptoms for 2 days or less. It helps lessen symptoms (such as stuffy nose, cough, sore throat, fever/chills, headache, body aches, tiredness) and shortens the recovery time by about 1 to 2 days.

Zanamivir may also be used to prevent the flu if you have been exposed to someone who already has the flu (such as a sick household member) or if there is a flu outbreak in the community. Talk to your doctor for more details.

This medication works by stopping the flu virus from growing. It is not a substitute for the flu vaccine.

If you have the flu, zanamivir does not reduce the risk of giving the flu to others.

 

HOW TO USE: Read the Patient Information Leaflet provided by your pharmacist before you start using zanamivir and each time you get a refill. Learn all usage instructions. If you have any questions, ask your doctor or pharmacist.

For flu treatment: inhale this medication through your mouth as directed by your doctor, usually 2 inhalations (1 blister per inhalation) twice a day (about 12 hours apart) for 5 days. If possible, on the first day of treatment, take two doses (2 inhalations each), waiting at least 2 hours between doses.

For flu prevention: inhale this medication through your mouth as directed by your doctor, usually 2 inhalations (1 blister per inhalation) once a day. The usual length of time you will take zanamivir is 10 days if there is a sick household member or 28 days if there is a flu outbreak in the community, or as directed by your doctor.

Remove the cover on the disk inhaler. Before use, check the mouthpiece to be sure it is clean and free of particles. Load the medication disk into the disk inhaler. Puncture one medication blister. Keep the disk inhaler level so that the medication will not spill out. Breathe out all the way through your mouth, put the mouthpiece into your mouth, and breathe in through your mouth as deeply as you can. This will draw the medication into your lungs. Hold your breath for a few seconds. To take another inhalation, advance to the next medication blister and repeat the process. Replace the cover of the disk inhaler.

Do not mix this powder medication with any liquids, including nebulizer liquids.

If a child is using this medication, a parent or other responsible adult should supervise the child to make sure it is used properly.

Start zanamivir as soon as possible. This medication works best when the amount of medicine in your body is kept at a constant level. Therefore, use this drug at evenly spaced intervals at the same time(s) every day.

Continue to use this medication for the full time prescribed, even if symptoms improve. Stopping the medication too early may result in a return of the infection, or failure to protect you from the flu.

If you have breathing problems (such as asthma, chronic obstructive pulmonary disease-COPD) and are scheduled to use inhaled bronchodilators (such as albuterol) at the same time as zanamivir, use the bronchodilator medication before using zanamivir. Ask your doctor or pharmacist for more details.

Tell your doctor if your condition persists or worsens or if new symptoms appear.

Consumer Overview Side Effect

SIDE EFFECTS: Dizziness may occur. Also, because this medication is an inhaled powder, you may experience increased coughing after using it. If either of these effects persists or worsens, tell your doctor or pharmacist promptly.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

This medication can cause breathing problems, which in rare cases can be fatal. If you experience trouble breathing such as wheezing or shortness of breath, stop using zanamivir and get medical help right away. Zanamivir is not recommended if you have lung/breathing problems. Discuss the risks and benefits with your doctor. However, if your doctor decides you should use zanamivir, have a quick-relief inhaled bronchodilator (such as albuterol inhaler) readily available.

The flu itself or zanamivir may rarely cause serious mental/mood changes. This may be more likely in children. Tell your doctor right away of any signs of unusual behavior, including confusion, agitation, self-injury.

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US -

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

 

Read the Relenza (zanamivir) Side Effects Center for a complete guide to possible side effects

Learn More »
 

PRECAUTIONS: Before using zanamivir, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients (such as lactose, milk proteins), which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: lung or breathing problems (such as asthma, chronic obstructive pulmonary disease-COPD).

This drug may make you dizzy. Do not drive, use machinery, or do any activity that requires alertness until you are sure you can perform such activities safely. Limit alcoholic beverages.

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

This drug may be less effective for young children. They may be unable to breathe in deeply enough using this inhaler device to get enough drug to benefit them.

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

It is unknown if this drug passes into breast milk. Consult your doctor before breast-feeding.

Consumer Overview Missed Dose

DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

Tell your doctor if you have received flu vaccine in the nose in the past 2 weeks. If given too closely together, zanamivir may interfere with the protection from flu vaccine given in the nose. Wait at least 2 days after the end of zanamivir treatment before receiving flu vaccine given in the nose.

 

OVERDOSE: If overdose is suspected, contact a poison control center or emergency room immediately. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center.

 

NOTES: Do not share this medication with others.

This medication has been prescribed for your current condition only. Do not use it later for another infection unless told to do so by your doctor. A different medication may be necessary in that case.

This medication is not a substitute for the flu vaccine. Consult your doctor about the risks and important benefits of receiving a yearly flu shot to lower your chances of getting the flu.

 

MISSED DOSE: If you miss a dose, use it as soon as you remember. Do not use the missed dose if it is within 2 hours of your next dose. In that case, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.

 

STORAGE: Store at room temperature in a dry place. Do not puncture the foil blister until you are ready to take your dose. Do not store in the bathroom. Keep all medications away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.

 

Information last revised January 2015. Copyright(c) 2015 First Databank, Inc.

Patient Detailed Side Effect

Brand Names: Relenza

Generic Name: zanamivir (Pronunciation: zan AM i vir)

  • What is zanamivir (Relenza)?
  • What are the possible side effects of zanamivir (Relenza)?
  • What is the most important information I should know about zanamivir (Relenza)?
  • What should I discuss with my healthcare provider before using zanamivir (Relenza)?
  • How should I use zanamivir (Relenza)?
  • What happens if I miss a dose (Relenza)?
  • What happens if I overdose (Relenza)?
  • What should I avoid while using zanamivir (Relenza)?
  • What other drugs will affect zanamivir (Relenza)?
  • Where can I get more information?

What is zanamivir (Relenza)?

 

Zanamivir is an antiviral medication. It blocks the actions of viruses in your body.

Zanamivir is used to treat flu symptoms caused by influenza virus in patients who have had symptoms for less than 2 days. Zanamivir may also be given to prevent influenza in people who may be exposed but do not yet have symptoms. Zanamivir will not treat the common cold.

Zanamivir should not be used in place of getting a yearly flu shot.The Centers for Disease Control recommends an annual flu shot to help protect you each year from new strains of influenza virus.

Zanamivir may also be used for purposes not listed in this medication guide.

What are the possible side effects of zanamivir (Relenza)?

 

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Some people using zanamivir have had rare side effects of confusion, delirium and self-injury. These symptoms have occurred most often in children. It is not known whether zanamivir was the exact cause of these symptoms. However, anyone using zanamivir should be watched closely for signs of confusion or unusual behavior. Call a doctor at once if you or the child using zanamivir has any of these symptoms.

Stop using zanamivir and call your doctor at once if you have wheezing or severe breathing problems, or if you feel like you might pass out.

Less serious side effects may include:

  • headache;
  • dizziness;
  • nausea, vomiting, diarrhea;
  • fever, chills, joint pain;
  • ear pain; or
  • cold symptoms such as stuffy nose, sneezing, sore throat;

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Read the Relenza (zanamivir) Side Effects Center for a complete guide to possible side effects

Learn More »
 

What is the most important information I should know about zanamivir (Relenza)?

 

Zanamivir should not be used in place of getting a yearly flu shot.The Centers for Disease Control recommends an annual flu shot to help protect you each year from new strains of influenza virus.

Before using zanamivir, tell your doctor if you have asthma, chronic obstructive pulmonary disease (COPD), or any other chronic lung condition. Serious or life-threatening bronchospasm (difficulty breathing) and other effects on the lungs can occur while using zanamivir. Stop using zanamivir and call your doctor at once if you have wheezing or severe breathing problems.

Do not use a nebulizer or ventilator to give zanamivir. Zanamivir inhalation powder should never be mixed with a liquid.

Treatment with zanamivir should start as soon as possible when flu symptoms appear, such as fever, chills, muscle aches, sore throat, and runny or stuffy nose.

Do not use this medication to treat flu symptoms in a child younger than 7 years old. Children as young as 5 years old may use the medication toprevent flu symptoms.

Do not use an inhaled nasal flu vaccine (FluMist) within 2 weeks before or 48 hours after using zanamivir. Zanamivir may interfere with the drug action of FluMist, making the vaccine less effective. Follow your doctor's instructions.

Some people using zanamivir have had rare side effects of confusion, delirium and self-injury. These symptoms have occurred most often in children. It is not known whether zanamivir was the exact cause of these symptoms. However, anyone using zanamivir should be watched closely for signs of confusion or unusual behavior. Call a doctor at once if you or the child using zanamivir has any of these symptoms.

Patient Detailed How Take

What should I discuss with my healthcare provider before using zanamivir (Relenza)?

 

You should not use this medication if you are allergic to zanamivir or to lactose (milk protein).

Before using zanamivir, tell your doctor if you have asthma, chronic obstructive pulmonary disease (COPD), or any other chronic lung condition. Serious or life-threatening bronchospasm (difficulty breathing) and other effects on the lungs can occur while using zanamivir.

If you have asthma, COPD, or other chronic lung disease, make sure you have a fast-acting inhaled bronchodilator available to treat any serious breathing problems that may occur while using zanamivir. Fast-acting bronchodilators include albuterol (Ventolin, Proventil), bitolterol (Tornalate), metaproterenol (Alupent), and pirbuterol (Maxair). Talk with your doctor about which medicine is best for you.

If you are scheduled to use a bronchodilator at the same time as zanamivir, use the bronchodilator first.

FDA pregnancy category C. It is not known whether zanamivir will harm an unborn baby. Tell your doctor if you are pregnant. Your doctor will decide whether you should receive zanamivir, especially if you have a high risk of infection with influenza.

It is not known whether zanamivir passes into breast milk or if it could harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.

Do not use this medication to treat flu symptoms in a child younger than 7 years old. Children as young as 5 years old may use the medication toprevent flu symptoms.

How should I use zanamivir (Relenza)?

 

Use exactly as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended. Follow the directions on your prescription label.

Treatment with zanamivir should start as soon as possible when flu symptoms appear, such as fever, chills, muscle aches, sore throat, and runny or stuffy nose.

Zanamivir is packaged in disk-shaped foil packs that contain 4 blisters of medicine. These disks are placed into a device called a DISKHALER that you will use to inhale the medicine. The device opens and loads a blister of zanamivir each time you use the inhaler. The disk device is not to be used with a spacer. Follow the patient instructions provided with the DISKHALER.

Do not use a nebulizer or ventilator to give zanamivir. Zanamivir inhalation powder should never be mixed with a liquid.

Do not use any other medicines in the DISKHALER. Always put the cover back on the device when not in use.

To treat flu symptoms: Use 2 inhalations every 12 hours for 5 days. Your doctor may tell you to use two doses on the first day of treatment, spaced at least 2 hours apart. On the following days, the doses should be spaced 12 hours apart. Follow your doctor's instructions.

To prevent flu symptoms: Use 2 inhalations every 24 hours for 10 to 28 days. Follow your doctor's instructions.

If you have a chronic respiratory disease such as asthma or COPD and you are scheduled to use an inhaled bronchodilator at the same time as zanamivir, use the inhaled bronchodilator before using zanamivir.

Use this medication for the full prescribed length of time. Your symptoms may improve before the infection is completely cleared. Tell your doctor if your symptoms do not improve, or if they get worse.

Store at room temperature away from moisture and heat. Throw away the DISKHALER after your treatment ends.

Patient Detailed Avoid Taking

What happens if I miss a dose (Relenza)?

 

Use the missed dose as soon as you remember. Skip the missed dose if it is within 2 hours of your next scheduled dose. Do not use extra medicine to make up the missed dose.

Call your doctor if you miss several doses.

What happens if I overdose (Relenza)?

 

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while using zanamivir (Relenza)?

 

Do not use an inhaled nasal flu vaccine (FluMist) within 2 weeks before or 48 hours after using zanamivir. Zanamivir may interfere with the drug action of FluMist, making the vaccine less effective. Follow your doctor's instructions.

What other drugs will affect zanamivir (Relenza)?

 

There may be other drugs that can interact with zanamivir. Tell your doctor about all medications you use. This includes prescription, over-the-counter, vitamin, and herbal products. Do not start a new medication without telling your doctor.

Where can I get more information?

 

Your pharmacist can provide more information about zanamivir.


Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.

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