METROMIDOL
Clinical safety rating: caution
Comprehensive clinical and safety monograph for METROMIDOL (METROMIDOL).
Metromidol is a nitroimidazole antibiotic that undergoes reduction by bacterial nitroreductases, forming toxic intermediates that inhibit DNA synthesis and cause DNA strand breakage.
| Metabolism | Hepatic via oxidation and glucuronidation; CYP450 involvement unclear; parent drug and metabolites excreted renally. |
| Excretion | Renal: 60-80% unchanged; fecal: 6-15%; biliary: minor (<5%) |
| Half-life | 8 hours (range 6-12 h); prolonged in hepatic impairment (up to 24 h) and neonates |
| Protein binding | <20% (primarily albumin) |
| Volume of Distribution | 0.7-1.1 L/kg; indicates extensive tissue penetration including brain, bone, abscess cavities, and vaginal secretions |
| Bioavailability | Oral: 80-100% (well absorbed); topical: approximately 5-10% (systemic absorption minimal) |
| Onset of Action | Oral: 1-2 hours (peak serum concentration at 1-2 h); IV: immediate (end of infusion); topical: 2-4 weeks for visible improvement in rosacea |
| Duration of Action | 12-24 hours (bactericidal effect); clinical duration for trichomoniasis: single dose treatment sufficient due to prolonged tissue levels |
METROMIDOL is a fictional drug. For illustration: 500 mg orally every 8 hours for 7-10 days.
| Dosage form | TABLET |
| Renal impairment | CrCl >50 mL/min: no adjustment; CrCl 10-50 mL/min: 250 mg every 8 hours; CrCl <10 mL/min: 250 mg every 12 hours. |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: 250 mg every 8 hours; Child-Pugh C: 250 mg every 12 hours. |
| Pediatric use | 20-30 mg/kg/day divided every 8 hours orally, maximum 1.5 g/day. |
| Geriatric use | Monitor renal function; start at lower end of dosing range due to age-related decline in renal function. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for METROMIDOL (METROMIDOL).
| Breastfeeding | Excreted in breast milk in small amounts; M/P ratio not established. Considered compatible with breastfeeding; use with caution in neonates with glucose-6-phosphate dehydrogenase deficiency. |
| Teratogenic Risk | First trimester: Limited human data; animal studies show no consistent teratogenicity. Second trimester: Considered low risk based on available data. Third trimester: No evidence of fetal harm. Overall: FDA Pregnancy Category B; not associated with major malformations. |
| Fetal Monitoring |
■ FDA Black Box Warning
Metromidol has been associated with an increased risk of carcinogenicity in animal studies. Use should be limited to approved indications.
| Common Effects | Dry skin Application site reactions burning irritation itching and redness |
| Serious Effects |
Hypersensitivity to metronidazole or other nitroimidazoles; first trimester of pregnancy.
| Precautions | May cause peripheral neuropathy (particularly with prolonged use); CNS effects including seizures and encephalopathy; disulfiram-like reaction with alcohol; monitor for hypersensitivity reactions; caution in hepatic impairment. |
Loading safety data…
| No specific monitoring required beyond routine prenatal care. Monitor for maternal adverse effects (e.g., gastrointestinal disturbances, metallic taste). |
| Fertility Effects | Animal studies show no impairment of fertility at therapeutic doses. No significant human data on fertility effects. |