Efficacy of doxepin in the treatment of chronic idiopathic urticaria.

Doxepin hydrochloride, a tricyclic antidepressant, was evaluated in a double-blind, placebo-controlled crossover trial for the treatment of chronic idiopathic urticaria in 16 adults. Efficacy was evaluated by symptom scores, concomitant antihistamine use, and suppression of histamine- and codeine-induced wheal response. Doxepin-treated subjects experienced fewer lesions (p less than 0.001), less waking hours with lesions (p less than 0.01), lesser degree of itch and/or discomfort (p less than 0.001), and less swelling or angioedema (p less than 0.001) as compared to placebo-treated subjects. Doxepin-treated subjects required less daily concomitant antihistamine use (mean 0.13 tablets versus 1.48 tablets, p less than 0.05). Doxepin also significantly suppressed histamine- and codeine-induced cutaneous wheal response as compared to placebo. Lethargy was commonly observed but diminished with continued use. Dry mouth and constipation were also commonly observed. We conclude that doxepin is an effective agent for the treatment of chronic idiopathic urticaria.