Definition of diphenhydramine in English:



mass nounMedicine
  • An antihistamine compound used for the symptomatic relief of allergies.

    A synthetic amine, usually used as a hydrochloride salt; chemical formula: C₁₇H₂₁NO

    • ‘The sedating antihistamine diphenhydramine is found in Benadryl, Tylenol PM and Sominex.’
    • ‘Amitriptyline, diazepam and diphenhydramine (in Tylenol PM) are considered risky for older individuals.’
    • ‘Take an antihistamine containing diphenhydramine (Benadryl, Tylenol Severe Allergy) or chlorpheniramine maleate (Chlor-Trimeton, Teldrin).’
    • ‘Examples of first-generation antihistamines include diphenhydramine and cyproheptadine (Periactin).’
    • ‘Suggested intravenous antihistamine pretreatment is diphenhydramine, in a dosage of 1 mg per kg, and cimetidine, in a dosage of 6 mg per kg.’


1940s: from diphen- (denoting the presence of two phenyl groups) + hydr- + amine.