Does Cimetidine Interact with Rapamycin?
Cimetidine and Rapamycin have a moderate drug interaction according to U.S. FDA drug labeling data. Weak/moderate CYP3A4/P-gp inhibitor that may increase sirolimus concentrations. Monitor and adjust dosage as needed. The mechanism involves modulation of cyp3a4 and p-gp. Patients taking both medications should consult their healthcare provider before starting, stopping, or changing the dosage of either drug. This information is based on official FDA drug labeling sourced from OpenFDA and the NIH National Library of Medicine.
- Severity
- Moderate
- Cimetidine Class
- Histamine-2 Receptor Antagonist
- Rapamycin Class
- mTOR Inhibitor Immunosuppressant
- Management
- Monitor for effects
- Data Source
- U.S. FDA via OpenFDA
How This Interaction Works
The interaction between Cimetidine and Rapamycin occurs because modulation of cyp3a4 and p-gp. Clinically, this means weak/moderate cyp3a4/p-gp inhibitor that may increase sirolimus concentrations. monitor and adjust dosage as needed. This is classified as a moderate interaction. While it may not require stopping either medication, your healthcare provider should be aware you are taking both so they can monitor for potential effects and adjust treatment if necessary.
What To Tell Your Doctor or Pharmacist
If you are taking Cimetidine and your doctor is considering prescribing Rapamycin (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
- Ask whether any dosage adjustments are needed
- Never stop or change either medication without first consulting your healthcare provider