Diphenhydramine (found in Benadryl and many OTC "PM" sleep aid products) is an antihistamine, and part of trazodone's own sedating effect comes from antihistamine activity too. Combining them can produce more drowsiness, dry mouth, and grogginess than either alone. Check ingredient labels on OTC cold, allergy, and sleep products, since diphenhydramine is common in all three.
Trazodone and diphenhydramine (Benadryl and similar OTC sleep aids)
Diphenhydramine works partly through the same antihistamine mechanism as trazodone's sedating effect, and combining them can cause excessive drowsiness.
Editorially reviewed
Key points
- Shares an antihistamine mechanism with trazodone's sedating effect
- Found in many "PM" cold, allergy, and sleep products
- Check OTC product labels for diphenhydramine before combining
Not medical advice. Always tell your prescriber and pharmacist about every medication, supplement, and substance you use so they can check for interactions specific to your situation.