METROCREAM
Clinical safety rating: caution
Comprehensive clinical and safety monograph for METROCREAM (METROCREAM).
Metrocream contains metronidazole, a nitroimidazole antibiotic. Its mechanism involves reduction of the nitro group by bacterial nitroreductases, forming toxic intermediates that damage DNA and inhibit nucleic acid synthesis. It also exhibits anti-inflammatory effects by reducing reactive oxygen species and modulating neutrophil chemotaxis.
| Metabolism | Hepatic metabolism via oxidation and glucuronidation. Metronidazole is metabolized by CYP450 enzymes, primarily CYP2A6 and CYP3A4, forming metabolites such as hydroxy metronidazole and acetic acid metabolite. |
| Excretion | Renal: 70-80% as unchanged drug and metabolites. Fecal/biliary: ~20%. |
| Half-life | Terminal elimination half-life: 6-8 hours. Not extended in renal impairment. |
| Protein binding | Metronidazole: <20% bound to plasma proteins. |
| Volume of Distribution | Vd: ~0.6-0.7 L/kg, indicating distribution into total body water. |
| Bioavailability | Topical: Systemic bioavailability approximately 0.1-1% of applied dose for metronidazole 1% cream. |
| Onset of Action | Topical: Improvement in inflammatory lesions of rosacea noted within 2-3 weeks of twice-daily application. |
| Duration of Action | Topical: Duration of action persists with continued application; sustained use required for maintenance. |
| Molecular Weight | 171.15 |
| Action Class | 5-Nitroimidazole (Antiprotozoal & Antibacterial) |
| Brand Substitutes | Unimegyl 400mg Tablet, Metgyl 400mg Tablet, Aldezol 400mg Tablet, Metrocon 400mg Tablet, Met 400mg Tablet, Tosgyl 200mg Tablet, Aristogyl 200mg Tablet, Metgyl 200mg Tablet, Metron 200mg Tablet, Unimegyl 200mg Tablet |
Topical, apply a thin film to affected area once or twice daily.
| Dosage form | CREAM |
| Renal impairment | No adjustment required for topical application. |
| Liver impairment | No adjustment required for topical application. |
| Pediatric use | Safety and efficacy not established in pediatric patients under 18 years. |
| Geriatric use | No specific dose adjustment recommended; use caution due to potential skin atrophy. |
| 1st trimester | Topical metronidazole is generally avoided in the first trimester due to limited safety data; alternative agents may be preferred. |
| 2nd trimester | Topical metronidazole is considered relatively safe; use only if clearly needed. |
| 3rd trimester | Topical metronidazole is considered safe; minimal systemic absorption. |
Clinical note
Comprehensive clinical and safety monograph for METROCREAM (METROCREAM).
| Placental transfer | Minimal placental transfer due to low systemic absorption after topical application; limited data suggest very low fetal exposure. |
| Breastfeeding | Topical metronidazole is generally compatible with breastfeeding due to minimal systemic absorption. Use caution if applied to large areas or broken skin. |
| Lactation Rating |
■ FDA Black Box Warning
None
| Serious Effects |
Hypersensitivity to metronidazole or any component of the formulation
| Precautions | Avoid contact with eyes. Use with caution in patients with blood dyscrasias or history of hypersensitivity to metronidazole. Prolonged use may result in overgrowth of non-susceptible organisms. Discontinue if irritation occurs. |
| Food/Dietary | No significant food interactions due to negligible systemic absorption. However, alcohol consumption should be avoided during treatment and for at least 48 hours after discontinuing metronidazole, as trace systemic absorption may cause disulfiram-like reactions (nausea, vomiting, flushing, headache). |
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| Teratogenic Risk | Topical metronidazole (MetroCream) is considered low risk for teratogenicity. In animal studies, no evidence of fetal harm was observed at topical doses. For oral metronidazole, data do not suggest an increased risk of major malformations; however, use in first trimester is generally avoided due to theoretical risk. For topical application, systemic absorption is minimal (approximately 2%), and the drug is considered safe throughout pregnancy, with no known fetal risks. |
| Fetal Monitoring | No specific maternal or fetal monitoring is required beyond routine prenatal care due to low systemic absorption. |
| Fertility Effects | No known adverse effects on fertility in males or females at topical doses. Systemic metronidazole has no established impact on fertility. |
| Clinical Pearls |
| Metronidazole topical cream is contraindicated in patients with a history of hypersensitivity to metronidazole or other nitroimidazole derivatives. Avoid contact with eyes, mucous membranes, or open wounds. Use during pregnancy only if clearly needed (FDA category B). Warn patients that topical metronidazole may cause transient skin irritation or dryness; if severe, discontinue use. Combine with sunscreen and photoprotective measures due to potential photosensitivity. For rosacea, clinical improvement may take 3–4 weeks; adherence is critical. Do not use with concomitant oral metronidazole or disulfiram-like reactions due to minimal systemic absorption. |
| Patient Advice | Apply a thin layer to affected areas once or twice daily as directed. · Wash hands before and after application; avoid contact with eyes, mouth, and nostrils. · Do not use cosmetics or other skin products on treated areas unless approved by your doctor. · May cause mild stinging, burning, or dryness; if severe, stop use and inform your physician. · Minimize sun exposure and use sunscreen daily as metronidazole may increase sun sensitivity. · Notify your doctor if you develop signs of allergic reaction: rash, itching, swelling, or trouble breathing. · Do not use more than prescribed; extended use may lead to bacterial resistance. · If you are pregnant, planning to become pregnant, or breastfeeding, discuss with your doctor before using. · Inform your doctor if you are taking oral metronidazole or have a history of blood disorders or neuropathy. |