II. Indications
- Pruritus
- Anxiety
III. Mechanism
- See Antihistamine
- H1 Receptor Antagonist (First Generation Antihistamine)
- Hydroxyzine is a piperazine derivative with Antihistamine, Antiemetic, and Anxiolytic activity
- Cetirizine (Zyrtec) is the active metabolite of Hydroxyzine
IV. Precautions
- Although FDA approved for children, FDA does not recommend routine Antihistamine use age <4 years
- Deaths have occurred in younger children related to Anticholinergic Toxicity
V. Dosing: Pruritus
- Adult: 25 to 100 mg orally or IM three to four times daily as needed
- Child (age 4 to 6 years): 50 mg/day divided four times daily orally or IM as needed
- Dose: 0.5 mg/kg up to 25-50 mg oral or intramuscular every 4-6 hours as needed
- Child (age >=6 years): 50 to 100 mg/day divided four times daily orally or IM as needed
VI. Dosing: Anxiety
- Adult: 50 to 100 mg orally three to four times daily as needed
VII. Adverse Effects
- See Antihistamine
- See Anticholinergic Toxicity
- Sedation
VIII. Safety
- Pregnancy category C
- Avoid in Lactation
IX. Resources
X. References
- Olson (2020) Clinical Pharmacology, Medmaster Miami, p. 146-7
- Hamilton (2020) Tarascon Pocket Pharmacopoeia