Mechanism of Action

At therapeutic doses, the first- and second-generation antihistamines are equilibrium-competitive inhibitors of H1-receptor-mediated responses. Certain second-generation drugs are noncompetitive inhibitors at high concentrations. Both first- and second-generation compounds have negligible abilities to block the H2-, H3-, or H4-receptors. The therapeutic effectiveness of these

TABLE 38.2 Representative H1Receptor Antagonists

Trade Duration of Sedative Anti-Motion Anticholinergic

Drug Name Action (hr) Activity Sickness Activity Activity

First-Generation Antihistamines

Ethanolamines Carbinoxamine Clemastine Diphenhydramine Dimenhydrinate Ethylenediamines Pyrilamine Tripelennamine

Alkylamines

Chlorpheniramine Brompheniramine Piperazines Cyclizine Hydroxyzine Meclizine

Phenothiazines

Promethazine Piperidines

Cyproheptadine

Second-Generation Antihistamines

Promethazine Piperidines

Cyproheptadine

Second-Generation Antihistamines

Periactin 4-6

Piperidines

10 Ways To Fight Off Cancer

10 Ways To Fight Off Cancer

Learning About 10 Ways Fight Off Cancer Can Have Amazing Benefits For Your Life The Best Tips On How To Keep This Killer At Bay Discovering that you or a loved one has cancer can be utterly terrifying. All the same, once you comprehend the causes of cancer and learn how to reverse those causes, you or your loved one may have more than a fighting chance of beating out cancer.

Get My Free Ebook


Post a comment