Metrogel-vaginal

Overdose

There is no human experience with overdosage of metronidazole vaginal gel. Vaginally applied MetroGel-Vaginal could be absorbed in sufficient amounts to produce systemic effects.

Contraindications

MetroGel-Vaginal is contraindicated in persons who have shown hypersensitivity to metronidazole, parabens, other ingredients of the formulation, or other nitroimidazole derivatives.

Psychotic reactions have been reported with co-administration disulfiram and oral metronidazole. Do not administer concurrently with or within 2 weeks of disulfiram.

Disulfiram-like reactions to alcohol have been reported with co-administration of oral metronidazole; do not consume ethanol or propylene glycol, during and for at least 24 hours following treatment.

Pharmaceutical form

Undesirable effects

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

The safety of MetroGel-Vaginal was evaluated in a randomized, double-blind, vehicle-controlled study in subjects with bacterial vaginosis. A total of 321 non-pregnant females with a mean age of 33.4 years (range 18 to 67 years) received MetroGel-Vaginal. Subjects were primarily Black/African American (58.3%) or White (39.3%). Subjects administered a single dose of MetroGel-Vaginal at bedtime on the first day of the study.

There were no deaths or serious adverse reactions in this trial. Adverse reactions were reported by 19.0% of subjects treated with MetroGel-Vaginal versus 16.1% of subjects treated with Vehicle Gel.

Adverse reactions occurring in ≥1% of subjects receiving MetroGel-Vaginal were: vulvovaginal candidiasis (5.6%), headache (2.2%), vulvovaginal pruritus (1.6%), nausea (1.6%), diarrhea (1.2%), and dysmenorrhea (1.2%). No subjects discontinued treatment due to adverse reactions.

The safety of MetroGel-Vaginal was evaluated in a multicenter, open-label study evaluating the safety and tolerability of MetroGel-Vaginal in 60 pediatric subjects between the ages of 12 and less than 18 years old all of whom were treated with a single dose of MetroGel-Vaginal administered once at bedtime intravaginally. Most subjects in this study were either Black/African-American, non-Hispanic (47%) or Hispanic (35%)

Safety in pediatric female subjects aged 12 to less than 18 years old was comparable to adult women. No deaths occurred and no subjects discontinued treatment due to adverse reactions. Adverse reactions occurring in ≥ 1% of pediatric subjects included: vulvovaginal discomfort (2%).

Other reactions that have been reported in association with the use of other formulations of metronidazole vaginal gel include: unusual taste and decreased appetite.

Other reactions that have been reported in association with the use of topical (dermal) formulations of metronidazole include skin irritation, transient skin erythema, and mild skin dryness and burning. None of these adverse reactions exceeded an incidence of 2% of patients.

The following adverse reactions and altered laboratory tests have been reported with the oral or parenteral use of metronidazole:

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

The most serious adverse reactions reported in patients treated with oral metronidazole have been convulsive seizures, encephalopathy, aseptic meningitis, optic and peripheral neuropathy, the latter characterized mainly by numbness or paresthesia of an extremity. In addition, patients have reported syncope, vertigo, incoordination, ataxia, confusion, dysarthria, irritability, depression, weakness, and insomnia.

Abdominal discomfort, nausea, vomiting, diarrhea, an unpleasant metallic taste, anorexia, epigastric distress, abdominal cramping, constipation, “furry” tongue, glossitis, stomatitis, pancreatitis, and modification of taste of alcoholic beverages.

Overgrowth of Candida in the vagina, dyspareunia, decreased libido, proctitis.

Reversible neutropenia, reversible thrombocytopenia.

Urticaria; erythematous rash; Stevens-Johnson Syndrome, toxic epidermal necrolysis, flushing; nasal congestion; dryness of the mouth, vagina, or vulva; fever; pruritus; fleeting joint pains.

Dysuria, cystitis, polyuria, incontinence, a sense of pelvic pressure, darkened urine.

MetroGel-Vaginal price

Therapeutic indications

MetroGel-Vaginal is indicated for the treatment of bacterial vaginosis in females 12 years of age and older.

Pharmacokinetic properties

Following a single, intravaginal 5 g dose of MetroGel-Vaginal (equivalent to 65 mg of metronidazole) to 20 healthy female subjects, a mean maximum serum metronidazole concentration (Cmax) of 239 ng/mL was observed (range: 114 to 428 ng/mL). The average time to achieve this Cmax was 7.3 hours (range: 4 to 18 hours). This Cmax is approximately 2% of the mean maximum serum concentration reported in healthy subjects administered a single, oral 500 mg dose of metronidazole tablets (mean Cmax = 12,785 ng/mL).

The extent of exposure [area under the curve (AUC)] of metronidazole, when administered as a single intravaginal 5 g dose of MetroGel-Vaginal (equivalent to 65 mg of metronidazole), was 5,434 ng•hr/mL (range: 1382 to 12744 ng•hr/mL). This AUC0-∞ is approximately 4% of the reported AUC of metronidazole following a single oral 500 mg dose of metronidazole (approximately 125,000 ng•hr/mL).

Name of the medicinal product

Qualitative and quantitative composition

Special warnings and precautions for use

Included as part of the PRECAUTIONS section.

Convulsive seizures, encephalopathy, aseptic meningitis, optic and peripheral neuropathy, the latter characterized mainly by numbness or paresthesia of an extremity, have been reported in patients treated with oral or intravenous metronidazole. MetroGel-Vaginal should be administered with caution to patients with central nervous system diseases. Discontinue promptly if abnormal neurologic signs develop.

Metronidazole has been shown to be carcinogenic at high doses administered orally in mice and rats. Unnecessary use of metronidazole should be avoided. Use of MetroGel-Vaginal should be reserved for the treatment of bacterial vaginosis.

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 dinucleotides (NAD + NADH). Interference is due to the similarity in absorbance peaks of NADH (340 nm) and metronidazole (322 nm) at pH 7.

Advise the patient to read the FDA-approved patient labeling (Patient Information and Instructions for Use).

Instruct the patient not to consume alcoholic beverages and preparations containing ethanol or propylene glycol during and for at least 24 hours after treatment with MetroGel-Vaginal.

Instruct the patient not to use MetroGel-Vaginal if disulfiram had been used within the last two weeks , and to inform their healthcare provider if they are taking oral anticoagulants, or lithium.

Instruct the patient not to engage in vaginal intercourse, or use other vaginal products (such as tampons or douches) following the single administration of MetroGel-Vaginal.

Advise women not to breastfeed during treatment with MetroGel-Vaginal and to discontinue breastfeeding for 2 days after treatment with MetroGel-Vaginal. Also advise a nursing mother that she may choose to pump and discard her milk during treatment with MetroGel-Vaginal and for 2 days after the therapy with MetroGel-Vaginal and, feed her infant stored human milk or formula.

Inform the patient to discontinue use and consult a healthcare provider if vaginal irritation occurs with use of MetroGel-Vaginal.

Instruct the patient that MetroGel-Vaginal is supplied as a single dose in a pre-filled applicator. See Instructions for Use for complete instructions on how to use the product and the vaginal applicator.

Metronidazole has shown evidence of carcinogenic activity in a number of studies involving chronic oral administration in mice and rats. Pulmonary tumors were reported in several mouse studies in which mice were dosed orally at 75 mg/kg and above (about 6 or more times the maximum recommended human dose based on mg/m²). Malignant lymphoma was reported at 66 mg/kg and above (about 5 or more times the maximum recommended human dose based on mg/m²). These 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). All these effects were statistically significant.

There were statistically significant increases in the incidence of mammary tumors, among female rats administered metronidazole at 270 mg/kg and above (about 40 times the maximum human dose based on mg/m²). Hepatic adenomas and carcinomas were observed in rats administered 300 mg/kg (about 45 times the maximum human dose based on mg/m²).

Two lifetime oral tumorigenicity studies in hamsters have been performed and reported to be negative at doses up to 80 mg/kg (about 10 times the maximum human dose based on mg/m²).

Carcinogenesis studies have not been conducted with MetroGel-Vaginal.

Although metronidazole has shown in vitro mutagenic activity in bacterial reverse mutation tests, it was negative in in vitro mammalian mutation systems including CHO/HGPRT and CH V79 lung cell assays. Metronidazole was not clastogenic in vitro chromosome aberration tests in CHO cells up to 5000 μg/mL but was positive in human and monkey peripheral blood lymphocytes at 0.1 μg/mL.

In general, numerous micronucleus studies in rats and mice have failed to demonstrate a potential for genetic damage up to single oral doses 3000 mg/kg in mice (about 225 times the maximum human dose based on mg/m²). However, a dose dependent increase in the frequency of micronuclei was observed in CFW mice after intraperitoneal injections of up to 160 mg/kg (about 12 times the maximum human dose based on mg/m²). Â Fertility studies have been performed in mice orally dosed up to 500 mg/kg (about 37 times the maximum human dose based on mg/m²) revealed no evidence of impaired fertility.

While no effects on fertility were observed in female rats dosed intraperitoneally at doses up to 1000 mg/kg (about 300 times the maximum human dose based on mg/m²), studies in male rats resulted in effects on testes and sperm production at oral doses of 100 mg/kg and above (about 30 times the maximum human dose based on mg/m²).

There are no data available on the use of MetroGel-Vaginal in pregnant women. Metronidazole usage in pregnancy has been associated with certain congenital anomalies (see Data). In animal reproduction studies, no fetotoxicity or teratogenicity was observed when metronidazole was administered orally, during organogenesis to pregnant rats and rabbits at up to 60 times and 30 times the recommended human dose based on body surface area comparison, respectfully(see Data).

The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively.

Human Data

Blood levels following MetroGel-Vaginal vaginal administration are lower than those achieved with oral metronidazole. Following a single intravaginal 5 g dose of MetroGel-Vaginal, mean maximum concentration (Cmax) and total exposure (AUC0-∞) are approximately 2% and 4%, respectively, of those following a single oral 500 mg dose of metronidazole tablets. Metronidazole crosses the placental barrier and enters the fetal circulation rapidly.

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 without cleft 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.

Animal Data

No fetotoxicity or teratogenicity was observed when metronidazole was administered orally to pregnant rabbits at up to 200 mg/kg (about 60 times the maximum human dose based on body surface area comparison). Similarly, no fetotoxic or teratogenic effects were observed in five studies in rats where dosing was administered orally in the diet or by gastric intubation at doses up to 200 mg/kg (about 30 times the maximum human dose based on body surface area comparison).

As well, no fetotoxicity or teratogenicity was observed when metronidazole was administered orally to pregnant mice at doses up to 100 mg/kg (about 7 times the maximum human dose based on body surface area comparison). However, some intrauterine deaths were observed in Swiss Webster mice administered metronidazole intraperitoneally at doses up to 15 mg/kg (about 1 times the maximum human dose based on body surface area comparison). The relationship of these intraperitoneal findings in mice to the vaginal use of MetroGel-Vaginal is unknown.

There is no information on the presence of metronidazole in human milk, or the effects on the breast-fed child, or the effects on milk production following intravaginal administration of MetroGel-Vaginal. Metronidazole is present in human milk following oral metronidazole administration, at concentrations similar to plasma concentrations (see Data). Since some metronidazole is systemically absorbed following vaginal administration of MetroGel-Vaginal, excretion in human milk following topical use is possible.

Because of the potential risk for tumorigenicity shown in animal studies with metronidazole, breastfeeding is not recommended during treatment with MetroGel-Vaginal and for 2 days (based on half-life) after MetroGel-Vaginal therapy ends (see Clinical Considerations).

A nursing mother may choose to pump and discard her milk during MetroGel-Vaginal therapy and for 2 days after MetroGel-Vaginal therapy ends, and feed her infant stored human milk or formula.

In a study of nursing mothers receiving oral metronidazole 600 (n=11) or 1200 (n=4) mg daily, mean maternal plasma concentrations were 5.0 and 12.5 mcg/mL, respectively, within 2 hours following administration; the milk: maternal plasma ratio was approximately 1.

The safety and effectiveness of MetroGel-Vaginal have been established in pediatric subjects between the ages of 12 and less than 18 years old. Use of MetroGel-Vaginal in this age group is supported by evidence from a multicenter, open-label safety and tolerability study in 60 pediatric subjects with bacterial vaginosis and, evidence from adequate and well-controlled studies in adult women,

The safety and effectiveness of MetroGel-Vaginal in pediatric subjects below the age of 12 years have not been established.

Clinical studies with MetroGel-Vaginal did not include sufficient numbers of subjects 65 years of age or older to determine whether they respond differently than younger subjects.

Dosage (Posology) and method of administration

A single-dose, pre-filled disposable applicator (which delivers approximately 5 g of gel containing 65 mg of metronidazole) administered once intravaginally. MetroGel-Vaginal should be administered at bedtime.

MetroGel-Vaginal is not for ophthalmic, dermal or oral use.