Dextromethorphan has 22 known drug interactions based on U.S. FDA drug labeling data. Of these, 4 are contraindicated combinations that should be avoided entirely. 4 are classified as major interactions requiring close medical supervision. Notable interactions include combinations with Rasagiline, Rasagiline Mesylate, Safinamide Mesylate. Patients taking Dextromethorphan should inform their healthcare provider of all current medications — including over-the-counter drugs and supplements — to avoid potentially harmful combinations. Data sourced from OpenFDA and the NIH National Library of Medicine.
- Total
- 22
- Contraindicated
- 4
- Major
- 4
- Moderate
- 13
- Minor
- 1
Contraindicated (4)
- Dextromethorphan + Rasagiline— Contraindicated due to risk of psychosis or bizarre behavior with MAO inhibitors including selective MAO-B inhibitors.
- Dextromethorphan + Rasagiline Mesylate— Combination with MAO inhibitors has been reported to cause brief episodes of psychosis or bizarre behavior. Dextromethor…
- Dextromethorphan + Safinamide Mesylate— Combination with MAOIs has been reported to cause episodes of psychosis or bizarre behavior.
- Dextromethorphan + Selegiline Hydrochloride— Combination with MAO inhibitors reported to cause brief episodes of psychosis or bizarre behavior.
Major (4)
- Dextromethorphan + Abiraterone— Abiraterone increased dextromethorphan Cmax and AUC 2.8- and 2.9-fold respectively. Avoid concomitant use or consider do…
- Dextromethorphan + Abiraterone Acetate— CYP2D6 substrate with 2.8-fold increase in Cmax and 2.9-fold increase in AUC when co-administered. Avoid co-administrati…
- Dextromethorphan + Methylene Blue— Concomitant use may result in serotonin syndrome with serious CNS reactions, potentially fatal.
- Dextromethorphan + Tipranavir— Probe substrate for CYP2D6; potent inhibition observed after first dose and steady state with APTIVUS/ritonavir.
Moderate (13)
- Dextromethorphan + Desvenlafaxine— Desvenlafaxine increases dextromethorphan levels. Reduce dose by up to one-half with 400 mg desvenlafaxine; no adjustmen…
- Dextromethorphan + Desvenlafaxine Er— Desvenlafaxine increases dextromethorphan exposure. Reduce dose by up to one-half with 400 mg desvenlafaxine; no adjustm…
- Dextromethorphan + Desvenlafaxine Succinate— Concomitant use increases exposure (Cmax and AUC). Reduce dose by up to one-half if co-administered with 400 mg desvenla…
- Dextromethorphan + Lasmiditan— Increased risk of serotonin syndrome when combined with lasmiditan; use with caution.
- Dextromethorphan + Memantine— Combined use of memantine with dextromethorphan has not been systematically evaluated and should be approached with caut…
- Dextromethorphan + Memantine Hydrochloride— Combined use with memantine has not been systematically evaluated. Both are NMDA antagonists and such use should be appr…
- Dextromethorphan + Memantine Hydrochloride And Donepezil Hydrochloride— Combined use of memantine with dextromethorphan (NMDA antagonist) has not been systematically evaluated and should be ap…
- Dextromethorphan + Paroxetine— Paroxetine inhibits CYP2D6, increasing dextromethorphan exposure. Decrease dextromethorphan dosage if needed with concom…
- Dextromethorphan + Paroxetine Hydrochloride— Paroxetine inhibits CYP2D6, increasing exposure of dextromethorphan. Dosage reduction may be needed.
- Dextromethorphan + Rolapitant— 2.3-fold increase in plasma concentrations with inhibitory effect persisting beyond 28 days.
- Dextromethorphan + Terbinafine— Terbinafine increases dextromethorphan/dextrorphan metabolite ratio by 16- to 97-fold, converting extensive CYP2D6 metab…
- Dextromethorphan + Terbinafine Hydrochloride— Terbinafine increases dextromethorphan/dextrorphan metabolite ratio by 16- to 97-fold, converting extensive metabolizers…
- Dextromethorphan + Terbinafine Tablets 250 Mg— Terbinafine increases dextromethorphan/dextrorphan metabolite ratio by 16- to 97-fold, potentially converting extensive …
Minor (1)
- Dextromethorphan + Methylnaltrexone Bromide— Subcutaneous methylnaltrexone did not significantly affect dextromethorphan metabolism in healthy subjects.