Does Cimetidine Interact with Duloxetine?
Cimetidine and Duloxetine have a contraindicated drug interaction according to U.S. FDA drug labeling data. Potent CYP1A2 inhibitor; should be avoided due to significant increase in duloxetine concentrations. The mechanism involves cyp1a2 inhibition. 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
- Contraindicated
- Cimetidine Class
- Histamine-2 Receptor Antagonist
- Management
- Do not take together
- Data Source
- U.S. FDA via OpenFDA
How This Interaction Works
The interaction between Cimetidine and Duloxetine occurs because cyp1a2 inhibition. Clinically, this means potent cyp1a2 inhibitor; should be avoided due to significant increase in duloxetine concentrations. Because of the severity of this interaction, these medications are contraindicated — meaning they should not be taken together under any circumstances. If you are currently taking both, contact your healthcare provider immediately to discuss alternatives.
What To Tell Your Doctor or Pharmacist
If you are taking Cimetidine and your doctor is considering prescribing Duloxetine (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 about alternative medications that do not interact with your current regimen
- Ask how frequently you should be monitored while these are co-prescribed
- Never stop or change either medication without first consulting your healthcare provider