Diphenhydramine (Benadryl)

Antihistamine

Blocks histamine release, thereby reducing bronchoconstriction, vasodilatation, edema, and capillary cell leakage.

Histamines Blocker, Has some sedative effects (SLIGHT)

• Onset: Varies
• Peak: Varies
• Duration: Varies
• Half Life: Varies

• Anaphylaxis- not used as first line agent (use epi)
• Allergic reaction
• Dystonic reaction due to phenothiazine’s

Asthma (use precaution because it's not always a contraindication, nursing mother)

None of emergencies

blurred vision, dries bronchial secretions, headache, palpitations

25-50mg

1-2mg/kg

50mg

Slow IV push, deep IM

Prefilled syringe