Does Terbinafine Hydrochloride Interact with Dextromethorphan?
CDI records a moderate classification for Terbinafine Hydrochloride and Dextromethorphan. The stored summary is: Terbinafine increases dextromethorphan/dextrorphan metabolite ratio by 16- to 97-fold, converting extensive metabolizers to poor metabolizer status. Careful monitoring and dose reduction may be required. The mechanism involves cyp450 2d6 inhibition. Patients taking both medications should consult their healthcare provider before starting, stopping, or changing the dosage of either drug. This record was extracted from drug labeling through openFDA. NIH/NLM RxNorm is used for drug identities. The summary and severity classification are CDI's processed information, not a verbatim source quotation. Product, route, and patient circumstances matter.
- Severity
- Moderate
- Management
- Monitor for effects
- Data Source
- U.S. FDA via OpenFDA
Recorded Mechanism
CYP450 2D6 inhibition
What To Tell Your Doctor or Pharmacist
If you are taking Terbinafine Hydrochloride and your doctor is considering prescribing Dextromethorphan (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