MetroCream Drug Interactions: What to Avoid and What to Tell Your Doctor

One of the advantages of MetroCream (metronidazole 0.75% topical cream) is that it is minimally absorbed into the bloodstream — meaning drug interactions are far less of a concern than with oral metronidazole. That said, some interactions are worth knowing about. Here's a complete guide to MetroCream drug interactions in 2026.

Why Drug Interactions Are Less Concerning With Topical Metronidazole

Drug interactions typically occur when two medications compete in the body — for metabolism, protein binding, or receptor sites. Because MetroCream is applied to the skin and is minimally absorbed (blood levels are less than 1% of an oral 250mg dose), systemic drug interactions are unlikely. Pharmacokinetic interactions that are significant with oral metronidazole are much less relevant with the topical cream.

However, there are a few interactions and precautions worth discussing with your doctor before starting MetroCream.

Key Drug Interactions to Know

1. Warfarin and Other Blood Thinners (Coumarin Anticoagulants)

Oral metronidazole is well-documented to enhance the anticoagulant effect of warfarin (Coumadin) and coumarin anticoagulants, prolonging the prothrombin time (PT/INR). This happens because metronidazole inhibits CYP2C9, the liver enzyme that metabolizes warfarin.

With topical MetroCream, systemic absorption is very low, so this interaction is unlikely to be clinically significant. However, the FDA's prescribing information notes that "the effect of topical metronidazole on prothrombin time is not known." If you take warfarin, tell your doctor and pharmacist before starting MetroCream, and monitor your INR as recommended.

2. Alcohol

Oral metronidazole can cause a disulfiram-like reaction with alcohol — nausea, vomiting, flushing, and headache. With topical MetroCream, systemic absorption is minimal, and this reaction is unlikely. However, some prescribers still recommend avoiding excessive alcohol during topical metronidazole treatment out of caution.

Also note: some topical skincare products contain alcohol as an inactive ingredient. Using MetroCream with alcohol-containing toners or astringents could potentially cause skin irritation, though this is a skin-level issue rather than a systemic drug interaction.

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3. Disulfiram (Antabuse)

Concurrent use of oral metronidazole and disulfiram (a medication used to treat alcohol dependence) has been associated with acute psychosis and confusion. This interaction is classified as major. While the risk with topical MetroCream is much lower due to minimal absorption, it's important to tell your doctor if you are taking disulfiram.

4. Lithium

Oral metronidazole has been reported to increase lithium toxicity by reducing lithium clearance. With topical MetroCream, the risk is theoretical and very low. Still, if you take lithium, let your doctor know before starting MetroCream so they can monitor accordingly.

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5. Other Topical Skincare Products

This is more of a skin-compatibility concern than a drug-drug interaction, but it's worth noting. Combining MetroCream with other active topical agents on the same area of skin can increase irritation. Medications to be careful with on rosacea-affected skin include:

Retinoids (tretinoin, adapalene): Can irritate rosacea-prone skin significantly; use with caution and physician guidance

Benzoyl peroxide: Can be drying and irritating on rosacea-affected skin; not typically recommended alongside MetroCream

Other topical antibiotics: No known dangerous interaction, but combining topical antibiotics is generally unnecessary and may increase resistance risk

What to Tell Your Doctor Before Starting MetroCream

Before your prescriber writes a MetroCream prescription, tell them about:

All medications you take, including blood thinners (especially warfarin)

Whether you take disulfiram (Antabuse) or lithium

Any history of blood dyscrasias (disorders of the blood)

Any allergy to metronidazole, nitroimidazoles, or the inactive ingredients in MetroCream

Whether you are pregnant, planning pregnancy, or breastfeeding

All other topical skincare products you use on your face

For a complete overview of MetroCream side effects beyond drug interactions, see our guide: MetroCream side effects: what to expect and when to call your doctor.

If you're having trouble finding MetroCream at a pharmacy near you, medfinder can contact pharmacies in your area to check which ones can fill it and text you the results.