Diphenhydramine

Examples: Benadryl Allergy. Check the exact formulation on your label.

What it is useful for

Can relieve allergies but carries a less favorable sedation and anticholinergic burden than newer options, particularly in older adults.

Availability: US OTC

When to expect a difference

Initial effect

Varies by formulation.

Full benefit

No single reliable time applies.

Use period

Use only as directed on the product label.

Stop or ask

Stop for an adverse reaction and seek advice.

How to use it

• Avoid alcohol and driving if drowsy. Check other nighttime products for overlap.

Use the dose on your specific package. Different concentrations and release types are not interchangeable.

Possible downsides

Drowsiness, Dry mouth, Urinary difficulty.

Check suitability

Check allergies, health conditions and all other medicines before use. The finder can flag common restrictions, but it is not a complete interaction checker.

Pregnancy, breastfeeding, children, immune suppression and postoperative care are outside this finder.