Related Experiment Video
Updated: Aug 6, 2026

Cheek Injection Model for Simultaneous Measurement of Pain and Itch-related Behaviors
Published on: September 27, 2019
Nonsedating H1 antihistamines in chronic urticaria
1Department of Dermatology, Medical College of Wisconsin, Milwaukee.
Abstract:
Histamine type 1 (H1) receptor antagonists are the principal therapy for chronic urticaria. Their usefulness, however, is sometimes compromised by undesirable central nervous system (CNS) side effects such as daytime sedation and anticholinergic side effects such as dry mouth. Second-generation, nonsedating antihistamines (terfenadine, astemizole, loratadine, and cetirizine hydrochloride) are just as effective as the potent first-generation antihistamines such as hydroxyzine. Yet they do not cause the CNS and anticholinergic side effects seen with the older agents. Cardiovascular side effects, which have been recently reported with terfenadine and astemizole, are dose related and rare, generally occurring in patients who overdose or who take concomitant medications that increase serum antihistamine levels. The second-generation antihistamines also offer twice daily and once daily dosage schedules, which are more convenient than the two- to four-times daily schedules of the older agents. They should therefore be considered first-line agents for the treatment of chronic urticaria. This article is a review of the role of the nonsedating antihistamines in the treatment of chronic urticaria.
Related Concept Videos
Cholinergic Antagonists: Pharmacokinetics
Sedatives and Hypnotics Drugs: Miscellaneous Agents
Melatonin congeners like ramelteon (Rozerem) and tasimelteon (Hetlioz) selectively bind to melatonin receptors (MT1 and MT2) and thus mimic the actions of melatonin, a hormone that regulates sleep-wake cycles. Tasimelteon is primarily used for non-24-hour sleep-wake disorder, common in blind patients. They are also used to treat conditions like insomnia...
Upper Respiratory Drugs: First and Second-Generation Antihistamines
Histamine binds to specific receptor sites, known as H1 receptors, on tissue cells, triggering inflammation and swelling. Antihistamines combat these effects by competing with histamine for these receptor sites. By...
Antiasthma Drugs: Leukotriene Modifiers
Leukotriene modifiers work through two distinct mechanisms:
Antiasthma Drugs: Mast Cell Stabilizers and Anti-IgE Drugs
Mast cell stabilizers, such as cromolyn (also known as sodium cromoglycate) and nedocromil (Tilade), are effective drugs in asthma management. These stabilizers hinder histamine release by skillfully obstructing the activation of mast cells and other cellular entities. Notably, they navigate this task without...
Acid Suppressive Drugs for Peptic Ulcer Disease: Histamine H2-Receptor Antagonists

