Newer antihistamines and histamine-release inhibitors.

Traditional H1 receptor antagonists are a mainstay of drug therapy for the allergic state, but cause numerous discomforting side effects which often hinder compliance. Newer H1 antagonists, including astemizole and terfenadine, appear remarkably free of central side effects and may provide a therapeutic breakthrough for clinicians. H2 antagonists have revolutionized drug therapy for hypersecretory states. Ranitidine appears to have fewer side effects than cimetidine at this stage in its utilization history, but has not been used as extensively. Other antisecretory agents of promise include some tricyclic antidepressants, prostaglandin derivatives, and potassium-hydrogen ATPase inhibitors. Newer histamine-release inhibitors (ketotifen, oxatimide e.g.) are effective orally and offer better patient compliance.