Diphenhydramine and Isoniazid interaction
Diphenhydramine and Isoniazid: the Diphenhydramine prescribing label describes an interaction that usually calls for monitoring, a dose change, or spacing the doses.
Moderate
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
Moderate
MAO inhibitors prolong and intensify the anticholinergic (drying) effects of antihistamines.
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.