DiphenhydramineOver the counter

Pronounced dye-fen-HY-drah-meen

Brand names: Benadryl

Type: Antihistamine (sedating) · All Allergy Medicines

What Diphenhydramine is used for

• Allergy symptoms and hives
• Allergic reactions, as an add-on treatment
• Occasional sleeplessness
• Motion sickness

Common side effects

• Drowsiness
• Dry mouth
• Dizziness
• Blurred vision
• Difficulty urinating

Important cautions

• It does not replace epinephrine for severe allergic reactions (anaphylaxis)
• Strongly sedating and confusing in older adults, in whom it is generally best avoided
• Many combination cold products contain it — check labels to avoid doubling up

How it comes

Tablets, capsules, liquid, cream, injection (hospital). This guide lists forms only — it never lists strengths or doses.