metronidazole vaginal (MetroGel Vaginal, Vandazole, Nuvessa)
Dosing and uses of MetroGel, Vandazole (metronidazole vaginal)
Adult dosage forms and strengths
vaginal geL
- 0.75% (MetroGel Vaginal, Vandazole)
- 1.3% (Nuvessa)
Bacterial Vaginosis
0.75%: One applicatorful intravaginal qDay/BID x5 days
1.3%: One applicatorful intravaginal once as a single-dose at bedtime
Pediatric dosage forms and strengths
vaginal geL
- 0.75% (MetroGel Vaginal, Vandazole)
- 1.3% (Nuvessa)
Bacterial Vaginosis
Premenarchal: Safety and efficacy not established
Postmenarchal adolescents
- 0.75%: One applicatorful intravaginal qDay/BID x5 days
- 1.3%: One applicatorful intravaginal once as a single-dose at bedtime
MetroGel, Vandazole (metronidazole vaginal) adverse (side) effects
>10%
Bacterial infection (12%)
1-10%
Headache (7%)
Pruritus (6%)
Abdominal pain (5%)
Nausea (3%)
Dysmenorrhea (3%)
Pharyngitis (2%)
Rash (1%)
Diarrhea (1%)
Breast pain (1%)
Metrorrhagia (1%)
Warnings
Contraindications
Hypersensitivity
Cautions
Psychotic reaction with disulfiram
Interaction with alcohol (disulfiram-like reaction); abdominal cramps, nausea, vomiting, headache, flushing
Discontinue alcohol consumption during and for at least 3 days after metronidazole therapy
PO and IV administration associated with seizures, encephalopathy, aseptic meningitis, and peripheral neuropathy
Carcinogenic in mice and rats; avoid unnecessary use
May interfere with lab assessments of AST, ALT, LDH, TG, and glucose hexokinase
Pregnancy and lactation
Pregnancy category: B
There are published data from case-control studies, cohort studies, and 2 meta-analyses that include more than 5000 pregnant women who used metronidazole systemically 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, >10 randomized, placebo-controlled clinical trials enrolled >5000 pregnant women to assess the use of systemic 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 systemic metronidazole exposure during pregnancy did not show an increased risk; however, the ability of these studies to detect such a signal was limited
Lactation: Excreted in human milk; caution advised
Following PO administration, concentrations in human milk are similar to concentrations in plasma; since some metronidazole is systemically absorbed following vaginal administration, excretion in human milk is possible
Potential for tumorigenicity shown in animal studies, a decision should be made whether to discontinue nursing or to discontinue metronidazole; breastfeeding women may choose to pump and discard milk for the duration of therapy, and for 24 hours after therapy ends and feed her infant stored human milk or formula
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of MetroGel, Vandazole (metronidazole vaginal)
Mechanism of action
Antibacterial agent; active in vitro to most strains of organisms associated with bacterial vaginosis including Bacteroides spp., Gardnerella vaginalis, Mobiluncus spp., and Peptostreptococcus spp.
Inhibits nucleic acid synthesis by disrupting DNA
Pharmacokinetics
Peak Plasma Time: 9.5 hr Peak
Plasma Concentration: 281 ng/mL (2% of PO dose)
AUC: 125,000 ng•hr/mL (5% of single oral dose)
