Antihistamines (2)

Question 1

Diphenhydramine

Answer 1

Brand Name: Benadryl

Classification: antihistamine

Action: Nonselectively blocks H1 and H2 histamine receptors

Indications: Allergies, Extrapyramidal reactions, Parkinson’s disease, Sedation, Anaphylaxis

Contraindications: Hypersensitivity, Glaucoma, Pregnancy

Dose: 25-50 mg

Routes: IV, IM, IO, PO

Adverse Effects: Drowsiness, Dizziness, Sedation, Dry Mouth

Other: If given IM give deep in muscle

Question 2

Cimetidine

Answer 2

Brand Name: Tagamet

Classification: Antihistamine

Action: Selectively blocks H2 histamine receptors

Indications: Duodenal/ peptic ulcer, anaphylaxis

Contraindications: Hypersensitivity

Dose: 300mg

Routes: IV, IM, PO

Adverse: Diarrhea, drowsiness, dizziness

Other: Can be used as an adjunct for severe allergic reactions and anaphylaxis