Does Phentermine And Topiramate Extended Release Interact with Hydrochlorothiazide?
Phentermine And Topiramate Extended Release and Hydrochlorothiazide have a moderate drug interaction according to U.S. FDA drug labeling data. Concomitant administration increases topiramate Cmax by 27% and AUC by 29%, requiring potassium monitoring. The mechanism involves increased topiramate exposure with potassium-wasting potential. 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
- Phentermine And Topiramate Extended Release Class
- Cytochrome P450 3A4 Inducers
- Hydrochlorothiazide Class
- Thiazide Diuretic
- Management
- Monitor for effects
- Data Source
- U.S. FDA via OpenFDA
How This Interaction Works
The interaction between Phentermine And Topiramate Extended Release and Hydrochlorothiazide occurs because increased topiramate exposure with potassium-wasting potential. Clinically, this means concomitant administration increases topiramate cmax by 27% and auc by 29%, requiring potassium monitoring. 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 Phentermine And Topiramate Extended Release and your doctor is considering prescribing Hydrochlorothiazide (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