Certain H1 antagonists, such as promethazine, have a local anesthetic effect.
Other H1-antihistamines having an important antimuscarinic activity like diphenhydramine and dimenhydrinate, are used in preventive and curative treatment of motion sickness, but scopolamine which has no antihistamine effect seems more effective than them in preventive treatment.
A self-medication that is used alone or in combination with pseudoephedrine sulfate for the symptomatic relief of seasonal allergic rhinitis.
Cetirizine, carboxyl derivative of hydroxyzine which is used as a sedative and anxiolytic, in addition to its H1-antihistamine effect, inhibits release of various cytokines and leukotrienes.
These antihistamines represent a heterogenous group of compounds with differing chemical structures, adverse effects, distribution, and metabolism.
Compared to the early (first generation) antihistamines, these non-sedating antihistamines have greater receptor specificity, lower penetration of BLOOD-BRAIN BARRIER, and are less likely to cause drowsiness or psychomotor impairment.
Azelastine is a H1-antihistamine usable by local route, in nasal pulverization, in the treatment of allergic rhinitis.
H1-antihistamines are used for supportive care of allergic manifestations, cutaneous (urticaria) or mucous membranes (rhinitis, hayfever, conjunctivitis). Insufficient alone to treat anaphylactic shock or edema of the larynx, they could prevent them.