Table 2 Antihistamines commonly used and indicated for the treatment of urticaria.

Second-generation H1-receptor antihistamines (first-line therapy)

Cetirizine (Reactine)

10-40 mg daily

5-10 mL (1-2 teaspoons) daily (children’s formulation)

Desloratadine (Aerius)

5-20 mg daily

2.5-5 mL (0.5-1.0 teaspoon) daily (children’s formulation)

Fexofenadine (Allegra)

120-480 mg daily

Not currently indicated for children under 12 years of age

Loratadine (Claritin)

10-40 mg daily

5-10 mL (1-2 teaspoons) daily (children’s formulation)

First-generation H1-receptor antihistamines (best used as adjunctive therapy for patients with nocturnal symptoms)

Hydroxyzine (Atarax)

25-50 mg, three to four times daily

Children < 6 years: 30 to 100 mg daily in divided doses

Diphenhydramine (Benadryl)

25-50 mg, every -6 hours

2.5-20 mL (0.5-4 teaspoons) every 4 to 6 hours (depending on age/weight)

Cyproheptadine (Periactin)

4-20 mg daily

2-4 mg, two to three times daily (depending on age/weight)

Chlorpheniramine (Chor-Tripolon)

4 mg every 4–6 hours

1 mg every 4–6 hours

Clemastine (Tavist-1)

1.34 - 2.68 mg, two to three times daily

1.34 mg, once or twice daily