Diphenhydramine and Meclizine interaction
Diphenhydramine and Meclizine: both prescribing labels describe an interaction that usually calls for monitoring, a dose change, or spacing the doses.
Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.
What the FDA labels say
From the Diphenhydramine label · effective 2026-03-05
Drug Interactions Diphenhydramine hydrochloride has additive effects with alcohol and other CNS depressants (hypnotics, sedatives, tranquilizers, etc).
From the Meclizine (Meclizine Hydrochloride) label · effective 2026-06-12
• Coadministration of meclizine hydrochloride with other CNS depressants, including alcohol, may result in increased CNS depression ( 7.1 ).
• CYP2D6 inhibitors: As meclizine is metabolized by CYP2D6, there is a potential for drug-drug interactions between meclizine hydrochloride and CYP2D6 inhibitors ( 7.2 ).
CYP2D6 Inhibitors Based on in-vitro evaluation, meclizine is metabolized by CYP2D6.
Therefore, there is a possibility for a drug interaction between meclizine hydrochloride and CYP2D6 inhibitors.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.