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Does Cimetidine Interact with Tacrolimus?

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.

Label evidence and limitations

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

Product scope: Topical tacrolimus ointment, not intravenous or oral tacrolimus.

Read the DailyMed label: TACROLIMUS OINTMENT 0.03% TACROLIMUS OINTMENT 0.1%
Section: Drug Interactions. Compared version 13, label date 2026-01-28. The linked label may be updated after this comparison.

This comparison uses the label identifier saved with the CDI record. The compared version may be newer than the original extraction.

AI-assisted source comparison dated 2026-10-16. This is a comparison of label text, not independent clinical review or an individual safety assessment. CDI's stored severity category is not an FDA-assigned rating. Confirm your exact medicines and formulations with your pharmacist or prescriber before changing treatment.

Stored CDI classification: Moderate
Cimetidine Class: Histamine-2 Receptor Antagonist
Tacrolimus Class: Calcineurin Inhibitor Immunosuppressant
Management: Confirm exact products with your pharmacist
Data Source: Product label via NLM DailyMed

What To Tell Your Doctor or Pharmacist

If you are taking Cimetidine and your doctor is considering prescribing Tacrolimus (or vice versa), make sure to:

Inform your doctor and pharmacist of all current medications, including over-the-counter drugs and supplements
Ask whether the benefits of combining these medications outweigh the risks for your specific situation
Ask what symptoms to watch for that would indicate the interaction is causing problems
Never stop or change either medication without first consulting your healthcare provider

💊 Cimetidine(Tagamet)+💊 Tacrolimus(Astagraf)

Severity & Interaction Details

🟡

Stored CDI classification: moderate

Named-drug label evidence

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

Stored CDI scale

MinorContra

On record

Yes

Drug A class

Histamine-2 Receptor Antagonist

Drug B class

Calcineurin Inhibitor Immunosuppressant

Source

NLP:tacrolimus

How to interpret this source comparison

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

About Cimetidine and Tacrolimus

Cimetidine is a Histamine-2 Receptor Antagonist, while Tacrolimus is a Calcineurin Inhibitor Immunosuppressant. You may recognize them by the brand names Tagamet and Astagraf. Tacrolimus additionally carries an FDA boxed warning, the FDA's strongest safety alert.

Source and Limitations

This record was produced by automated extraction from drug-label information, including AI processing. The summary and mechanism are not verbatim FDA quotations. The drug profiles below may describe different formulations from the source label. Confirm the exact product and route with your pharmacist. This page does not establish independent clinical review.

📖 Source: NLP:tacrolimus

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How this information is prepared: CDI uses automated extraction, including AI, to summarize drug labeling from openFDA and includes separately identified curated-reference records. RxNorm helps identify medications; it does not verify interaction claims. Extracted summaries and CDI severity classifications can contain errors and are not verbatim FDA statements or independent clinical review. Maintained by CheckDrugInteractions.com. See our methodology or report a correction at support@checkdruginteractions.com.

Data sourced from U.S. FDA drug labeling via openFDA and the NIH National Library of Medicine, supplemented with a small number of well-established interactions from curated clinical references. For informational purposes only. Always consult your pharmacist or physician.