Drug interactions
Cimetidine + Tacrolimus
Severity: Moderate
Cimetidine and Tacrolimus: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Cimetidine can increase tacrolimus blood concentrations in some patients, with risk of nephrotoxicity, neurotoxicity and hyperglycemia. Tacrolimus has a narrow therapeutic index.
What this interaction means in plain words
Cimetidine and Tacrolimus can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Cimetidine belongs to Gastrointestinal Tract; Tacrolimus belongs to Miscellaneous.
Why it happens
Cimetidine inhibits CYP3A4 and intestinal P-glycoprotein, reducing tacrolimus metabolism and efflux.
What to do
Check tacrolimus trough levels and renal function after starting or stopping cimetidine and adjust the dose. Prefer an alternative acid suppressant such as famotidine.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Cimetidine
- Cimetidine + Dofetilide Contraindicated
- Cimetidine + Fezolinetant Contraindicated
- Alfentanil + Cimetidine Major
- Atazanavir + Cimetidine Major
- Carmustine + Cimetidine Major
- Cimetidine + Citalopram Major
Other interactions of Tacrolimus
- Adenovirus types 4 and 7 live + Tacrolimus Contraindicated
- Bcg vaccine live + Tacrolimus Contraindicated
- Cidofovir + Tacrolimus Contraindicated
- Cyclosporin + Tacrolimus Contraindicated
- Influenza virus vaccine quadrivalent intranasal + Tacrolimus Contraindicated
- Measles mumps and rubella vaccine live + Tacrolimus Contraindicated
Frequently asked questions
Can I take Cimetidine with Tacrolimus?
MediHelp rates the interaction as moderate. Cimetidine and Tacrolimus can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Cimetidine can increase tacrolimus blood concentrations in some patients, with risk of nephrotoxicity, neurotoxicity and hyperglycemia. Tacrolimus has a narrow therapeutic index.
How serious is the interaction between Cimetidine and Tacrolimus?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Check tacrolimus trough levels and renal function after starting or stopping cimetidine and adjust the dose. Prefer an alternative acid suppressant such as famotidine.
What other medicines interact with Cimetidine?
MediHelp also lists interactions of Cimetidine with, for example, Dofetilide, Fezolinetant, Alfentanil. The full list is on the Cimetidine page.
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