Drugs Details

Drugs Info of Flagyl, Flagyl 375, Flagyl ER
Drugs Details
  • Drugs Type  : Multum
  • Date : 10th Mar 2015 02:43 am
  • Brand Name : Flagyl, Flagyl 375, Flagyl ER
  • Generic Name : metronidazole (Pronunciation: me troe NI da zole)
Descriptions

FLAGYL (metronidazole) tablets, 250 mg or 500 mg is an oral formulation of the synthetic nitroimidazole antimicrobial, 2-methyl-5-nitro-1H-imidazole-1-ethanol, which has the following structural formula:

 

FLAGYL® (metronidazole) Structural Formula Illustration

 

FLAGYL (metronidazole) tablets contain 250 mg or 500 mg of metronidazole. Inactive ingredients include cellulose, FD&C Blue No. 2 Lake, hydroxypropyl cellulose, hypromellose, polyethylene glycol, stearic acid, and titanium dioxide.

 

What are the possible side effects of metronidazole (Flagyl, Flagyl 375, Flagyl ER)?

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.

Call your doctor at once if you have any of these serious side effects:

  • numbness or tingling in your hands or feet;
  • white patches or sores inside your mouth or on your lips;
  • pain or burning when you urinate;
  • diarrhea that is watery or bloody;
  • vision problems, pain behind your eyes;
  • trouble concentrating, slurred speech, mood or behavior changes,...

Read All Potential Side Effects and See Pictures of Flagyl »

What are the precautions when taking metronidazole (Flagyl)?

Before taking metronidazole, tell your doctor or pharmacist if you are allergic to it; or to other nitroimidazoles such as tinidazole; or if you have any other allergies. This product may contain inactive ingredients, 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: liver problems, nervous system disorders (e.g., seizures), blood disorders, Crohn's disease.

Avoid alcoholic beverages while taking this medication and for at least 1 day (3 days if you are taking the oral capsules) after finishing this medicine because drinking alcohol may result in severe stomach upset/cramps, nausea, vomiting, headache and flushing.

This drug...

Read All Potential Precautions of Flagyl »

 

This monograph has been modified to include the generic and brand name in many instances.

Indications

Symptomatic Trichomoniasis

FLAGYL is indicated for the treatment of T. vaginalis infection in females and males when the presence of the trichomonad has been confirmed by appropriate laboratory procedures (wet smears and/or cultures).

Asymptomatic Trichomoniasis

FLAGYL is indicated in the treatment of asymptomatic T. vaginalis infection in females when the organism is associated with endocervicitis, cervicitis, orcervical erosion. Since there is evidence that presence of the trichomonad can interfere with accurate assessment of abnormal cytological smears, additional smears should be performed after eradication of the parasite.

Treatment of Asymptomatic Sexual Partners

T. vaginalis infection is a venereal disease. Therefore, asymptomatic sexual partners of treated patients should be treated simultaneously if the organism has been found to be present, in order to prevent reinfection of the partner. The decision as to whether to treat an asymptomatic male partner who has a negative culture or one for whom no culture has been attempted is an individual one. In making this decision, it should be noted that there is evidence that a woman may become reinfected if her sexual partner is not treated. Also, since there can be considerable difficulty in isolating the organism from the asymptomatic male carrier, negative smears and cultures cannot be relied upon in this regard. In any event, the sexual partner should be treated with FLAGYL in cases of reinfection.

Amebiasis

FLAGYL is indicated in the treatment of acute intestinal amebiasis (amebic dysentery) and amebic liver abscess.

In amebic liver abscess, FLAGYL therapy does not obviate the need foraspiration or drainage of pus.

Anaerobic Bacterial Infections

FLAGYL is indicated in the treatment of serious infections caused by susceptible anaerobic bacteria. Indicated surgical procedures should be performed in conjunction with FLAGYL therapy. In a mixed aerobic and anaerobic infection, antimicrobials appropriate for the treatment of the aerobic infection should be used in addition to FLAGYL.

INTRA-ABDOMINAL INFECTIONS, including peritonitis, intra-abdominal abscess, and liver abscess, caused by Bacteroides species including the B. fragilis group (B. fragilis, B. distasonis, B. ovatus, B. thetaiotaomicron, B. vulgatus), Clostridium species, Eubacterium species, Peptococcus species, and Peptostreptococcus species.

SKIN AND SKIN STRUCTURE INFECTIONS caused by Bacteroides species including the B. fragilis group, Clostridium species, Peptococcus species,Peptostreptococcus species, and Fusobacterium species.

GYNECOLOGIC INFECTIONS, including endometritis, endomyometritis, tubo-ovarian abscess, and postsurgical vaginal cuff infection, caused byBacteroides species including the B. fragilis group, Clostridium species,Peptococcus species, Peptostreptococcus species, and Fusobacteriumspecies.

BACTERIAL SEPTICEMIA caused by Bacteroides species including the B. fragilis group and Clostridium species.

BONE AND JOINT INFECTIONS, (as adjunctive therapy), caused byBacteroides species including the B. fragilis group.

CENTRAL NERVOUS SYSTEM (CNS) INFECTIONS, including meningitisand brain abscess, caused by Bacteroides species including the B. fragilisgroup.

LOWER RESPIRATORY TRACT INFECTIONS, including pneumonia,empyema, and lung abscess, caused by Bacteroides species including the B. fragilis group.

ENDOCARDITIS caused by Bacteroides species including the B. fragilisgroup.

To reduce the development of drug-resistant bacteria and maintain the effectiveness of FLAGYL and other antibacterial drugs, FLAGYL should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria. When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy.

Dosage Administration

Trichomoniasis

In the Female

One-day treatment - two grams of FLAGYL, given either as a single dose or in two divided doses of one gram each, given in the same day.

Seven-day course of treatment - 250 mg three times daily for seven consecutive days. There is some indication from controlled comparative studies that cure rates as determined by vaginal smears and signs and symptoms, may be higher after a seven-day course of treatment than after a one-day treatment regimen.

The dosage regimen should be individualized. Single-dose treatment can assure compliance, especially if administered under supervision, in those patients who cannot be relied on to continue the seven-day regimen. A seven-day course of treatment may minimize reinfection by protecting the patient long enough for the sexual contacts to obtain appropriate treatment. Further, some patients may tolerate one treatment regimen better than the other.

Pregnant patients should not be treated during the first trimester (seeCONTRAINDICATIONS). In pregnant patients for whom alternative treatment has been inadequate, the one-day course of therapy should not be used, as it results in higher serum levels which can reach the fetalcirculation (see PRECAUTIONS, Pregnancy).

When repeat courses of the drug are required, it is recommended that an interval of four to six weeks elapse between courses and that the presence of the trichomonad be reconfirmed by appropriate laboratory measures. Total and differential leukocyte counts should be made before and after re-treatment.

In the Male: Treatment should be individualized as it is for the female.

Amebiasis

Adults

For acute intestinal amebiasis (acute amebic dysentery): 750 mg orally three times daily for 5 to 10 days.

For amebic liver abscess: 500 mg or 750 mg orally three times daily for 5 to 10 days.

Pediatric patients: 35 to 50 mg/kg/24 hours, divided into three doses, orally for 10 days.

Anaerobic Bacterial Infections

In the treatment of most serious anaerobic infections, intravenous metronidazole is usually administered initially.

The usual adult oral dosage is 7.5 mg/kg every six hours (approx. 500 mg for a 70-kg adult). A maximum of 4 g should not be exceeded during a 24-hour period.

The usual duration of therapy is 7 to 10 days; however, infections of the bone and joint, lower respiratory tract, and endocardium may require longer treatment.

Dosage Adjustments

Patients with Severe Hepatic Impairment

For patients with severe hepatic impairment (Child-Pugh C), the dose of FLAGYL should be reduced by 50% (see CLINICAL PHARMACOLOGY andPRECAUTIONS).

Patients Undergoing Hemodialysis

Hemodialysis removes significant amounts of metronidazole and its metabolites from systemic circulation. The clearance of metronidazole will depend on the type of dialysis membrane used, the duration of the dialysis session, and other factors. If the administration of metronidazole cannot be separated from the hemodialysis session, supplementation of metronidazole dosage following the hemodialysis session should be considered, depending on the patient's clinical situation (see CLINICAL PHARMACOLOGY).

How Supplied

FLAGYL 250-mg tablets are round, blue, film coated, with SEARLE and 1831 debossed on one side and FLAGYL and 250 on the other side; supplied as bottles of 50 and 100.

 

NDC NUMBER SIZE
25-1831-50 bottle of 50
25-1831-31 bottle of 100

 

FLAGYL 500-mg tablets are oblong, blue, film coated, with FLAGYL debossed on one side and 500 on the other side; bottles of 50 and 100.

 

NDC NUMBER SIZE
25-1821-50 bottle of 50
25-1821-31 bottle of 100

 

Storage And Stability

Store below 77°F (25°C) and protect from light.

Distributed by: G.D. Searle, Division of Pfizer Inc., NY, NY 10017. Revised June 2013

This monograph has been modified to include the generic and brand name in many instances.

Side Effects

The following reactions have been reported during treatment with metronidazole:

Central Nervous System

The most serious adverse reactions reported in patients treated with metronidazole have been convulsive seizures, encephalopathy, asepticmeningitis, optic and peripheral neuropathy, the latter characterized mainly by numbness or paresthesia of an extremity. Since persistent peripheralneuropathy has been reported in some patients receiving prolonged administration of metronidazole, patients should be specifically warned about these reactions and should be told to stop the drug and report immediately to their physicians if any neurologic symptoms occur. In addition, patients have reported headache, syncope, dizziness, vertigo, incoordination, ataxia, confusion, dysarthria, irritability, depression, weakness, and insomnia (seeWARNINGS).

Gastrointestinal

The most common adverse reactions reported have been referable to thegastrointestinal tract, particularly nausea, sometimes accompanied by headache, anorexia, and occasionally vomiting; diarrhea; epigastric distress; and abdominal cramping and constipation.

Mouth

A sharp, unpleasant metallic taste is not unusual. Furry tongue, glossitis, and stomatitis have occurred; these may be associated with a sudden overgrowth of Candida which may occur during therapy.

Dermatologic

Erythematous rash and pruritus.

Hematopoietic

Reversible neutropenia (leukopenia); rarely, reversible thrombocytopenia.

Cardiovascular

Flattening of the T-wave may be seen in electrocardiographic tracings.

Hypersensitivity

Urticaria, erythematous rash, Stevens-Johnson Syndrome, toxic epidermalnecrolysis, flushing, nasal congestion, dryness of the mouth (or vagina orvulva), and fever.

Renal

Dysuria, cystitis, polyuria, incontinence, and a sense of pelvic pressure. Instances of darkened urine have been reported by approximately one patient in 100,000. Although the pigment which is probably responsible for this phenomenon has not been positively identified, it is almost certainly a metabolite of metronidazole and seems to have no clinical significance.

Other

Proliferation of Candida in the vagina, dyspareunia, decrease of libido,proctitis, and fleeting joint pains sometimes resembling “serum sickness.” Rare cases of pancreatitis, which generally abated on withdrawal of the drug, have been reported.

Patients with Crohn's disease are known to have an increased incidence ofgastrointestinal and certain extraintestinal cancers. There have been some reports in the medical literature of breast and colon cancer in Crohn's disease patients who have been treated with metronidazole at high doses for extended periods of time. A cause and effect relationship has not been established. Crohn's disease is not an approved indication for FLAGYL tablets.

Read the Flagyl (metronidazole) Side Effects Center for a complete guide to possible side effects

Learn More »

Interactions

 

Disulfiram

Psychotic reactions have been reported in alcoholic patients who are using metronidazole and disulfiram concurrently. Metronidazole should not be given to patients who have taken disulfiram within the last two weeks (seeCONTRAINDICATIONS).

Alcoholic Beverages

Abdominal cramps, nausea, vomiting, headaches, and flushing may occur if alcoholic beverages or products containing propylene glycol are consumed during or following metronidazole therapy (see CONTRAINDICATIONS).

Warfarin And Other Oral Anticoagulants

Metronidazole has been reported to potentiate the anticoagulant effect of warfarin and other oral coumarin anticoagulants, resulting in a prolongation of prothrombin time. When FLAGYL is prescribed for patients on this type of anticoagulant therapy, prothrombin time and INR should be carefully monitored.

Lithium

In patients stabilized on relatively high doses of lithium, short-term metronidazole therapy has been associated with elevation of serum lithium and, in a few cases, signs of lithium toxicity. Serum lithium and serum creatinine levels should be obtained several days after beginning metronidazole to detect any increase that may precede clinical symptoms of lithium intoxication.

Busulfan

Metronidazole has been reported to increase plasma concentrations of busulfan, which can result in an increased risk for serious busulfan toxicity. Metronidazole should not be administered concomitantly with busulfan unless the benefit outweighs the risk. If no therapeutic alternatives to metronidazole are available, and concomitant administration with busulfan is medically needed, frequent monitoring of busulfan plasma concentration should be performed and the busulfan dose should be adjusted accordingly.

Drugs That Inhibit CYP450 Enzymes

The simultaneous administration of drugs that decrease microsomal liver enzyme activity, such as cimetidine, may prolong the half-life and decrease plasma clearance of metronidazole.

Drugs That Induce CYP450 Enzymes

The simultaneous administration of drugs that induce microsomal liver enzymes, such as phenytoin or phenobarbital, may accelerate the elimination of metronidazole, resulting in reduced plasma levels; impaired clearance of phenytoin has also been reported.

Drug/Laboratory Test Interactions

Metronidazole may interfere with certain types of determinations of serum chemistry values, such as aspartate aminotransferase (AST, SGOT), alanine aminotransferase (ALT, SGPT), lactate dehydrogenase (LDH), triglycerides, and glucose hexokinase. Values of zero may be observed. All of the assays in which interference has been reported involve enzymatic coupling of the assay to oxidation-reduction of nicotinamide adenine dinucleotide (NAD+ **********NADH). Interference is due to the similarity in absorbance peaks of NADH (340 nm) and metronidazole (322 nm) at pH 7.

This monograph has been modified to include the generic and brand name in many instances.

Warnings

Central And Peripheral Nervous System Effects

Encephalopathy and peripheral neuropathy: Cases of encephalopathy and peripheral neuropathy (including optic neuropathy) have been reported with metronidazole.

Encephalopathy has been reported in association with cerebellar toxicity characterized by ataxia, dizziness, and dysarthria. CNS lesions seen on MRIhave been described in reports of encephalopathy. CNS symptoms are generally reversible within days to weeks upon discontinuation of metronidazole. CNS lesions seen on MRI have also been described as reversible.

Peripheral neuropathy, mainly of sensory type has been reported and is characterized by numbness or paresthesia of an extremity.

Convulsive seizures have been reported in patients treated with metronidazole.

Aseptic meningitis: Cases of aseptic meningitis have been reported with metronidazole. Symptoms can occur within hours of dose administration and generally resolve after metronidazole therapy is discontinued.

The appearance of abnormal neurologic signs and symptoms demands the prompt evaluation of the benefit/risk ratio of the continuation of therapy (seeADVERSE REACTIONS).

 
 

Precautions

General

Hepatic Impairment

Patients with hepatic impairment metabolize metronidazole slowly, with resultant accumulation of metronidazole in the plasma. For patients with severe hepatic impairment (Child-Pugh C), a reduced dose of FLAGYL is recommended. For patients with mild to moderate hepatic impairment, no dosage adjustment is needed but these patients should be monitored for metronidazole associated adverse events (see CLINICAL PHARMACOLOGY and DOSAGE AND ADMINISTRATION).

Renal Impairment

Patients with end-stage renal disease may excrete metronidazole and metabolites slowly in the urine, resulting in significant accumulation of metronidazole metabolites. Monitoring for metronidazole associated adverse events is recommended (see CLINICAL PHARMACOLOGY).

Fungal Superinfections

Known or previously unrecognized candidiasis may present more prominent symptoms during therapy with FLAGYL and requires treatment with a candidacidal agent.

Use In Patients With Blood Dyscrasias

Metronidazole is a nitroimidazole and should be used with caution in patients with evidence of or history of blood dyscrasia. A mild leukopenia has been observed during its administration; however, no persistent hematologic abnormalities attributable to metronidazole have been observed in clinical studies. Total and differential leukocyte counts are recommended before and after therapy.

Drug-Resistant Bacteria And Parasites

Prescribing FLAGYL in the absence of a proven or strongly suspected bacterial or parasitic infection or a prophylactic indication is unlikely to provide benefit to the patient and increases the risk of the development of drug-resistant bacteria and parasites.

Carcinogenesis, Mutagenesis, Impairment Of Fertility

Tumors affecting the liver, lungs, mammary, and lymphatic tissues have been detected in several studies of metronidazole in rats and mice, but not hamsters.

Pulmonary tumors have been observed in all six reported studies in the mouse, including one study in which the animals were dosed on an intermittent schedule (administration during every fourth week only).Malignant liver tumors were increased in male mice treated at approximately 1500 mg/m² (similar to the maximum recommended daily dose, based on body surface area comparisons). Malignant lymphomas and pulmonary neoplasms were also increased with lifetime feeding of the drug to mice. Mammary and hepatic tumors were increased among female rats administered oral metronidazole compared to concurrent controls. Two lifetime tumorigenicity studies in hamsters have been performed and reported to be negative.

Metronidazole has shown mutagenic activity in in vitro assay systems including the Ames test. Studies in mammals in vivo have failed to demonstrate a potential for genetic damage.

Metronidazole failed to produce any adverse effects on fertility or testicular function in male rats at doses up at 400 mg/kg/day (similar to the maximum recommended clinical dose, based on body surface area comparisons) for 28 days. However, rats treated at the same dose for 6 weeks or longer wereinfertile and showed severe degeneration of the seminiferous epithelium in the testes as well as marked decreases in testicular spermatid counts and epididymal sperm counts. Fertility was restored in most rats after an eight week, drug-free recovery period.

Pregnancy

Teratogenic Effects

Pregnancy Category B

There are no adequate and well controlled studies of FLAGYL in pregnant women. There are published data from case-control studies, cohort studies, and 2 meta-analyses that include more than 5000 pregnant women who used metronidazole during pregnancy. Many studies included first trimester exposures. One study showed an increased risk of cleft lip, with or withoutcleft palate, in infants exposed to metronidazole in-utero; however, these findings were not confirmed. In addition, more than ten randomized placebo-controlled clinical trials enrolled more than 5000 pregnant women to assess the use of antibiotic treatment (including metronidazole) for bacterial vaginosis on the incidence of preterm delivery. Most studies did not show an increased risk for congenital anomalies or other adverse fetal outcomes following metronidazole exposure during pregnancy. Three studies conducted to assess the risk of infant cancer following metronidazole exposure during pregnancy did not show an increased risk; however, the ability of these studies to detect such a signal was limited.

Metronidazole crosses the placental barrier and its effects on the human fetal organogenesis are not known. Reproduction studies have been performed in rats, rabbits, and mice at doses similar to the maximum recommended human dose based on body surface area comparisons. There was no evidence of harm to the fetus due to metronidazole.

Nursing Mothers

Metronidazole is present in human milk at concentrations similar to maternal serum levels, and infant serum levels can be close to or comparable to infant therapeutic levels. Because of the potential for tumorigenicity shown for metronidazole in mouse and rat studies, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother. Alternatively, a nursing mother may choose to pump and discard human milk for the duration of metronidazole therapy, and for 24 hours after therapy ends and feed her infant stored human milk or formula.

Geriatric Use

In elderly geriatric patients, monitoring for metronidazole associated adverse events is recommended (see CLINICAL PHARMACOLOGY,PRECAUTIONS). Decreased liver function in geriatric patients can result in increased concentrations of metronidazole that may necessitate adjustment of metronidazole dosage (see DOSAGE AND ADMINISTRATION).

Pediatric Use

Safety and effectiveness in pediatric patients have not been established, except for the treatment of amebiasis.

This monograph has been modified to include the generic and brand name in many instances.

OverDose

Single oral doses of metronidazole, up to 15 g, have been reported in suicide attempts and accidental overdoses. Symptoms reported include nausea, vomiting, and ataxia.

Oral metronidazole has been studied as a radiation sensitizer in the treatment of malignant tumors. Neurotoxic effects, including seizures and peripheral neuropathy, have been reported after 5 to 7 days of doses of 6 to 10.4 g every other day.

Treatment: There is no specific antidote for Flagyl (metronidazole) overdose; therefore, management of the patient should consist of symptomatic and supportive therapy.

ContrainDications

Flagyl (metronidazole) is contraindicated in patients with a prior history of hypersensitivity to metronidazole or other nitroimidazole derivatives.

In patients with trichomoniasis, Flagyl (metronidazole) is contraindicated during the first trimester of pregnancy. (See WARNINGS)

This monograph has been modified to include the generic and brand name in many instances.

Clinical Pharamacology

Absorption

Disposition of metronidazole in the body is similar for both oral and intravenous dosage forms. Following oral administration, metronidazole is well absorbed, with peak plasma concentrations occurring between one and two hours after administration.

Plasma concentrations of metronidazole are proportional to the administered dose. Oral administration of 250 mg, 500 mg, or 2,000 mg produced peak plasma concentrations of 6 mcg/mL, 12 mcg/mL, and 40 mcg/mL, respectively. Studies reveal no significant bioavailability differences between males and females; however, because of weight differences, the resulting plasma levels in males are generally lower.

Distribution

Metronidazole is the major component appearing in the plasma, with lesser quantities of metabolites also being present. Less than 20% of the circulating metronidazole is bound to plasma proteins. Metronidazole appears incerebrospinal fluid, saliva, and breast milk in concentrations similar to those found in plasma. Bactericidal concentrations of metronidazole have also been detected in pus from hepatic abscesses.

Metabolism/Excretion

The major route of elimination of metronidazole and its metabolites is via the urine (60% to 80% of the dose), with fecal excretion accounting for 6% to 15% of the dose. The metabolites that appear in the urine result primarily from side-chain oxidation [1-(ßhydroxyethyl)-2-hydroxymethyl-5-nitroimidazole and 2-methyl-5-nitroimidazole-1-ylacetic acid] and glucuronide conjugation, with unchanged metronidazole accounting for approximately 20% of the total. Both the parent compound and the hydroxyl metabolite possess in vitro antimicrobial activity.

Renal clearance of metronidazole is approximately 10 mL/min/1.73 m². The average elimination half-life of metronidazole in healthy subjects is eight hours.

Renal Impairment

Decreased renal function does not alter the single-dose pharmacokinetics of metronidazole.

Subjects with end-stage renal disease (ESRD; CLCR= 8.1±9.1 mL/min) and who received a single intravenous infusion of metronidazole 500 mg had no significant change in metronidazole pharmacokinetics but had 2-fold higher Cmax of hydroxy-metronidazole and 5-fold higher Cmax of metronidazole acetate, compared to healthy subjects with normal renal function (CLCR= 126±16 mL/min). Thus, on account of the potential accumulation of metronidazole metabolites in ESRD patients, monitoring for metronidazole associated adverse events is recommended (see PRECAUTIONS).

Effect of Dialysis

Following a single intravenous infusion or oral dose of metronidazole 500 mg, the clearance of metronidazole was investigated in ESRD subjects undergoing hemodialysis or continuous ambulatory peritoneal dialysis(CAPD). A hemodialysis session lasting for 4 to 8 hours removed 40% to 65% of the administered metronidazole dose, depending on the type of dialyzer membrane used and the duration of the dialysis session. If the administration of metronidazole cannot be separated from the dialysis session, supplementation of metronidazole dose following hemodialysis should be considered (see DOSAGE AND ADMINISTRATION). A peritonealdialysis session lasting for 7.5 hours removed approximately 10% of the administered metronidazole dose. No adjustment in metronidazole dose is needed in ESRD patients undergoing CAPD.

Hepatic Impairment

Following a single intravenous infusion of 500 mg metronidazole, the mean AUC24 of metronidazole was higher by 114% in patients with severe (Child-Pugh C) hepatic impairment, and by 54% and 53% in patients with mild (Child-Pugh A) and moderate (Child-Pugh B) hepatic impairment, respectively, compared to healthy control subjects. There were no significant changes in the AUC24 of hydroxyl-metronidazole in these hepatically impaired patients. A reduction in metronidazole dosage by 50% is recommended in patients with severe (Child-Pugh C) hepatic impairment (see DOSAGE AND ADMINISTRATION). No dosage adjustment is needed for patients with mild to moderate hepatic impairment. Patients with mild to moderate hepatic impairment should be monitored for metronidazole associated adverse events (see PRECAUTIONS and DOSAGE AND ADMINISTRATION).

Geriatric Patients

Following a single 500 mg oral or IV dose of metronidazole, subjects > 70 years old with no apparent renal or hepatic dysfunction had a 40% to 80% higher mean AUC of hydroxy-metronidazole (active metabolite), with no apparent increase in the mean AUC of metronidazole (parent compound), compared to young healthy controls < 40 years old. In geriatric patients, monitoring for metronidazole associated adverse events is recommended (see PRECAUTIONS).

Pediatric Patients

In one study, newborn infants appeared to demonstrate diminished capacity to eliminate metronidazole. The elimination half-life, measured during the first 3 days of life, was inversely related to gestational age. In infants whose gestational ages were between 28 and 40 weeks, the corresponding elimination half-lives ranged from 109 to 22.5 hours.

Microbiology

Mechanism of Action

Metronidazole exerts antibacterial effects in an anaerobic environment by the following possible mechanism: Once metronidazole enters the organism, the drug is reduced by intracellular electron transport proteins. Because of this alteration to the metronidazole molecule, a concentration gradient is created and maintained which promotes the drug's intracellular transport. Presumably, free radicals are formed which, in turn, react with cellular components resulting in death of the bacteria.

Metronidazole is active against most obligate anaerobes, but does not possess any clinically relevant activity against facultative anaerobes or obligate aerobes.

Activity In Vitro and In Vivo

Metronidazole has been shown to be active against most isolates of the following bacteria both in vitro and in clinical infections as described in theINDICATIONS AND USAGE section.

Gram-positive Anaerobes

Clostridium species
Eubacterium species
Peptococcus
 species
Peptostreptococcus
 species

Gram-negative Anaerobes

Bacteroides fragilis group (B. fragilis, B. distasonis, B. ovatus, B. thetaiotaomicron, B.vulgatus)
Fusobacterium species

Protozoal Parasites

Entamoeba histolytica 
Trichomonas vaginalis

The following in vitro data are available, but their clinical significance is unknown:

Metronidazole exhibits in vitro minimum inhibitory concentrations (MIC's) of < 8 mcg/mL or less against most ( ≥ 90%) isolates of the following bacteria; however, the safety and effectiveness of metronidazole in treating clinical infections due to these bacteria have not been established in adequate and well-controlled clinical trials.

Gram-negative Anaerobes

Bacteroides fragilis group (B. caccae, B. uniformis)
Prevotella species (P. bivia, P. buccae, P. disiens)

Susceptibility Test Methods

When available, the clinical microbiology laboratory should provide the results of in vitro susceptibility test results for antimicrobial drug products used in resident hospitals to the physician as periodic reports that describe the susceptibility profile of nosocomial and community-acquired pathogens. These reports should aid the physician in selecting an antibacterial drug product for treatment.

Anaerobic Techniques

Quantitative methods are used to determine minimum inhibitory concentrations provide reproducible estimates of the susceptibility of bacteria to antimicrobial compounds. For anaerobic bacteria susceptibility to metronidazole can be determined by the reference broth or agar dilution method1,2. The MIC values obtained should be interpreted according to the following criteria:

Susceptibility Test Interpretive Criteria for Metronidazole

 

MIC (MCG/ML) INTERPRETATION
≤ 8 Susceptible (S)
16 Intermediate (I)
≥ 32 Resistant (R)

 

For protozoal parasites: Standardized tests do not exist for use in clinical microbiology laboratories.

A report of “Susceptible” indicates that the antimicrobial is likely to inhibit growth of the pathogen if the antimicrobial compound reaches the concentrations at the infection site necessary to inhibit growth of the pathogen. A report of “Intermediate” indicates that the result should be considered equivocal, and, if the microorganism is not fully susceptible to alternative, clinically feasible drugs, the test should be repeated. This category implies possible clinical applicability in body sites where the drug is physiologically concentrated or in situations where a high dosage of the drug product is physiologically concentrated or in situations where a high dosage of the drug product can be used. This category also provides a buffer zone that prevents small uncontrolled technical factors from causing major discrepancies in interpretation. A report of “Resistant” indicates that the antimicrobial is not likely to inhibit growth of the pathogen if the antimicrobial compound reaches the concentrations usually achievable at the infection site; other therapy should be selected.

Quality Control

Standardized susceptibility test procedures require the use of laboratory controls to monitor and ensure the accuracy and precision of supplies and reagents used in the assay, and the techniques of the individuals performing the test.1,2 Standard metronidazole powder should provide a value within the MIC ranges noted in the following table:

Agar and Broth Acceptable Quality Control Ranges for Metronidazole

Acceptable Quality Control Ranges for Metronidazole

QC STRAIN MINIMUM INHIBITORY CONCENTRATION (MCG/ML)
AGAR BROTH
Bacteroides fragilis ATCC 25285 0.25-1.0 0.25-2.0
Bacteroides thetaiotaomicron ATCC 29741 0.5-2.0 0.5-4.0

 

REFERENCES

1. Clinical and Laboratory Standards Institute (CLSI). Methods for Antimicrobial Susceptibility Testing of Anaerobic Bacteria; Approved Standard -Eighth Edition. CLSI document M11-A8. Clinical and Laboratory Standards Institute, 950 West Valley Road, Suite 2500, Wayne, PA 19087 USA, 2012.

2. Clinical and Laboratory Standards Institute (CLSI). Performance Standards for Antimicrobial Susceptibility Testing; Twenty-third Informational Supplement, CLSI document M100-S23. CLSI document M100-S23, Clinical and Laboratory Standards Institute, 950 West Valley Road, Suite 2500, Wayne, Pennsylvania 19087, USA, 2013.

This monograph has been modified to include the generic and brand name in many instances.

Patient Information

Interaction With Alcohol

Discontinue consumption of alcoholic beverages or products containing propylene glycol while taking FLAGYL and for at least three days afterward because abdominal cramps, nausea, vomiting, headaches, and flushing may occur (see CONTRAINDICATIONS and PRECAUTIONS: DRUG INTERACTIONS).

Treatment Of Bacterial And Parasitic Infections

Patients should be counseled that FLAGYL should only be used to treat bacterial and parasitic infections. FLAGYL does not treat viral infections (e.g., the common cold). When FLAGYL is prescribed to treat a bacterial infection, patients should be told that although it is common to feel better early in the course of therapy, the medication should be taken exactly as directed. Skipping doses or not completing the full course of therapy may (1) decrease the effectiveness of the immediate treatment and (2) increase the likelihood that bacteria will develop resistance and will not be treatable by FLAGYL in the future.

This monograph has been modified to include the generic and brand name in many instances.

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.

 

METRONIDAZOLE - ORAL

 

(MET-roe-NYE-da-zole)

 

COMMON BRAND NAME(S): Flagyl

 

USES: Metronidazole is used to treat a variety of infections. It belongs to a class of antibiotics known as nitroimidazoles. It works by stopping the growth of bacteria and protozoa.

This antibiotic only treats bacterial and protozoal infections. It will not work for viral infections (e.g., common cold, flu). Unnecessary use or overuse of any antibiotic can lead to its decreased effectiveness.

Metronidazole can also be used in combination with anti-ulcer medications to treat certain types of stomach ulcers.

 

HOW TO USE: This medication may be taken with food or a full glass of water or milk to prevent stomach upset. Dosage is based on your medical condition, the type of infection being treated, and your response to therapy.

Antibiotics work best when the amount of medicine in your body is kept at a constant level. Therefore, take this drug at evenly spaced intervals.

Continue to take this medication until the full prescribed amount is finished, even if symptoms disappear after a few days. Stopping the medication too early may allow bacteria/protozoa to continue to grow, which may result in a relapse of the infection.

Inform your doctor if your condition persists or worsens.

Consumer Overview Side Effect

SIDE EFFECTS: Dizziness, headache, diarrhea, nausea, stomach pain, loss of appetite, constipation, changes in taste, and dry mouth may occur. If any of these effects persist or worsen, notify your doctor or pharmacist promptly.

This drug may cause urine to darken in color. This is harmless.

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.

Tell your doctor immediately if any of these unlikely but serious side effects occur: unsteadiness, seizures, mental/mood changes (such as confusion), numbness/tingling of hands/feet, painful urination.

Tell your doctor immediately if any of these rare but very serious side effects occur: eye pain, severe/persistent headache, sudden vision changes, stiff/painful neck, sore throat, persistent fever, unusual bleeding/bruising, severe stomach pain, persistent nausea/vomiting.

Use of this medication for prolonged or repeated periods may result in oral thrush or a new vaginal yeast infection (oral or vaginal fungal infection). Contact your doctor if you notice white patches in your mouth, a change in vaginal discharge, or other new symptoms.

A very serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction may include: 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 Flagyl (metronidazole) Side Effects Center for a complete guide to possible side effects

Learn More »
 

PRECAUTIONS: Before taking metronidazole, tell your doctor or pharmacist if you are allergic to it; or to other nitroimidazoles such as tinidazole; or if you have any other allergies. This product may contain inactive ingredients, 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: liver problems, nervous system disorders (e.g., seizures), blood disorders, Crohn's disease.

Avoid alcoholic beverages while taking this medication and for at least 1 day (3 days if you are taking the oral capsules) after finishing this medicine because drinking alcohol may result in severe stomach upset/cramps, nausea, vomiting, headache and flushing.

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.

The elderly may be at greater risk for side effects while using this drug.

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

This medication passes into breast milk. Discuss the risks and benefits with your doctor before breast-feeding. If you are prescribed the single-dose treatment, your doctor may direct you to interrupt breast-feeding for a short time after the dose. Consult your doctor for more details.

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.

Some products that may interact with this drug include: alcohol-containing products (e.g., cough and cold syrups, aftershave), lopinavir/ritonavir oral solution, "blood thinners" (such as warfarin), busulfan, cimetidine, fluorouracil, lithium, mebendazole, live bacterial vaccines, drugs for seizures (such as phenobarbital, phenytoin).

Avoid disulfiram for 2 weeks before and during treatment with this medication.

Although most antibiotics probably do not affect hormonal birth control such as pills, patch, or ring, some antibiotics may decrease their effectiveness. This could cause pregnancy. Examples include rifamycins such as rifampin or rifabutin. Be sure to ask your doctor or pharmacist if you should use additional reliable birth control methods while using this antibiotic.

This medication may interfere with certain laboratory tests (including liver function tests, blood triglyceride levels), possibly causing false test results. Make sure laboratory personnel and your doctors know you use this drug.

 

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. Symptoms of overdose may include nausea, vomiting, severe dizziness, and seizures.

 

NOTES: Do not share this medication with others.

Treatment of certain infections (trichomoniasis) may require that sexual partners be treated as well to avoid re-infection. During therapy, refrain from sexual intercourse or always use a condom.

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 those cases.

Laboratory and/or medical tests (e.g., blood counts) should be performed from time to time to monitor your progress or check for side effects. Consult your doctor for more details.

 

MISSED DOSE: If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.

 

STORAGE: Tablets should be stored at room temperature below 77 degrees F (25 degrees C) away from light. Capsules should be stored at or below room temperature between 59-77 degrees F (15-25 degrees C). Do not store in the bathroom. Keep all medicines 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 for more details about how to safely discard your product.

 

Information last revised August 2013. Copyright(c) 2013 First Databank, Inc.

Patient Detailed Side Effect

Brand Names: Flagyl, Flagyl 375, Flagyl ER

Generic Name: metronidazole (Pronunciation: me troe NI da zole)

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

What is metronidazole (Flagyl)?

 

Metronidazole is an antibiotic. It fights bacteria in your body.

Metronidazole is used to treat bacterial infections of the vagina, stomach, skin, joints, and respiratory tract. This medication will not treat a vaginal yeast infection.

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

Flagyl 375 mg

capsule, gray/green, imprinted with FLAGYL, 375mg

What are the possible side effects of metronidazole (Flagyl)?

 

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

Call your doctor at once if you have any of these serious side effects:

  • numbness or tingling in your hands or feet;
  • white patches or sores inside your mouth or on your lips;
  • pain or burning when you urinate;
  • diarrhea that is watery or bloody;
  • vision problems, pain behind your eyes;
  • trouble concentrating, slurred speech, mood or behavior changes, tremors, muscle twitching, seizure (convulsions);
  • fever, chills, muscle pain, confusion, headache, sore throat, neck stiffness, increased sensitivity to light, drowsiness, nausea and vomiting; or
  • severe skin reaction -- fever, sore throat, swelling in your face or tongue, burning in your eyes, skin pain, followed by a red or purple skin rash that spreads (especially in the face or upper body) and causes blistering and peeling.

Less serious side effects may include:

  • stomach pain, diarrhea;
  • dizziness, loss of balance;
  • vaginal itching or discharge;
  • dry mouth or unpleasant metallic taste;
  • cough, sneezing, runny or stuffy nose; or
  • swollen or sore tongue.

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 Flagyl (metronidazole) Side Effects Center for a complete guide to possible side effects

Learn More »
 

What is the most important information I should know about metronidazole (Flagyl)?

 

Take this medication for the full prescribed length of time. Your symptoms may improve before the infection is completely cleared. Skipping doses may also increase your risk of further infection that is resistant to antibiotics. Metronidazole will not treat a viral infection such as the common cold or flu.

Do not drink alcohol while you are taking metronidazole and for at least 3 days after you stop taking it. You may have unpleasant side effects such as fast heartbeats, warmth or redness under your skin, tingly feeling, nausea, and vomiting.

Side Effects Centers
  • Flagyl
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Patient Detailed How Take

What should I discuss with my healthcare provider before taking metronidazole (Flagyl)?

 

You should not use this medication if you are allergic to metronidazole, or if you are in the first trimester of pregnancy. Tell your doctor if you are pregnant or plan to become pregnant during treatment.

Before taking metronidazole, tell your doctor if you are allergic to any drugs, or if you have:

  • liver disease;
  • a stomach or intestinal disease such as Crohn's disease;
  • a blood cell disorder such as anemia (lack of red blood cells) or leukopenia (lack of white blood cells);
  • epilepsy or other seizure disorder; or
  • nerve disorders.

If you have any of these conditions, you may need a dose adjustment or special tests to safely take this medication.

Metronidazole can pass into breast milk and may harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.

How should I take metronidazole (Flagyl)?

 

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

Take the extended-release metronidazole tablet (Flagyl ER) on an empty stomach, at least 1 hour before or 2 hours after eating a meal.

Do not crush, chew, or break an extended-release tablet. Swallow it whole. Breaking the pill may cause too much of the drug to be released at one time.

Take this medication for the full prescribed length of time. Your symptoms may improve before the infection is completely cleared. Skipping doses may also increase your risk of further infection that is resistant to antibiotics. Metronidazole will not treat a viral infection such as the common cold or flu.

To be sure this medication is not causing harmful effects, your blood may need to be tested often. Your liver function may also need to be tested. Visit your doctor regularly.

This medication can cause unusual results with certain medical tests. Tell any doctor who treats you that you are using metronidazole.

Store at room temperature away from moisture and heat.

Side Effects Centers
  • Flagyl
  • Flagyl ER

Patient Detailed Avoid Taking

What happens if I miss a dose (Flagyl)?

 

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

What happens if I overdose (Flagyl)?

 

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

Overdose symptoms may include nausea, vomiting, dizziness, loss of balance or coordination, numbness and tingling, or seizures (convulsions).

What should I avoid while taking metronidazole (Flagyl)?

 

Do not drink alcohol while you are taking metronidazole and for at least 3 days after you stop taking it. You may have unpleasant side effects such as fast heartbeats, warmth or redness under your skin, tingly feeling, nausea, and vomiting.

Check the labels of any medicines or food products you use to make sure they do not contain alcohol.

Antibiotic medicines can cause diarrhea, which may be a sign of a new infection. If you have diarrhea that is watery or bloody, stop taking metronidazole and call your doctor. Do not use anti-diarrhea medicine unless your doctor tells you to.

What other drugs will affect metronidazole (Flagyl)?

 

Tell your doctor about all other medicines you use, especially:

  • cimetidine (Tagamet);
  • seizure medication such as phenytoin (Dilantin) or phenobarbital (Luminal, Solfoton);
  • a blood thinner such as warfarin (Coumadin, Jantoven);
  • lithium (Lithobid, Eskalith, others); or
  • disulfiram (Antabuse).

This list is not complete and other drugs may interact with metronidazole. 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 metronidazole.


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.

Copyright 1996-2013 Cerner Multum, Inc. Version: 10.01. Revision date: 2/14/2011.

Your use of the content provided in this service indicates that you have read,understood and agree to the End-User License Agreement,which can be accessed by clicking on this link.

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