cimetidine and tacrolimus: label evidence and limits

The tacrolimus ointment label names cimetidine among CYP3A4 inhibitors requiring caution in patients with widespread or erythrodermic skin disease. Formal topical interaction studies were not conducted; systemic interaction is described as unlikely but not excluded.

Which products this evidence covers

Topical tacrolimus ointment, not intravenous or oral tacrolimus.

What this finding does and does not establish

This source cannot be used to describe every tacrolimus formulation. A pharmacist should assess the exact product and patient circumstances.

Supporting label passage

Formal topical drug interaction studies with tacrolimus ointment have not been conducted. Based on its extent of absorption, interactions of tacrolimus ointment with systemically administered drugs are unlikely to occur but cannot be ruled out (see CLINICAL PHARMACOLOGY ). The concomitant administration of known CYP3A4 inhibitors in patients with widespread and/or erythrodermic disease should be done with caution. Some examples of such drugs are erythromycin, itraconazole, ketoconazole, fluconazole, calcium channel blockers and cimetidine.

Read the product label on DailyMed. Section: Drug Interactions. Compared label version 13, dated 2026-01-28.

How this brief was prepared

This brief uses an AI-assisted source comparison dated 2026-10-16. The label version and supporting passage were checked again on 2026-10-25. Independent clinical review has not been recorded. The comparison does not validate CDI's severity category or determine individual treatment.

Discuss your exact medicines with your pharmacist

Ask whether the cited formulation and route apply to your products and circumstances. Confirm medication decisions with your pharmacist or prescriber before changing treatment.

Check your medication list with CDI.