What are the different types of antiallergic drugs?
Antiallergic drugs are classified into the following major categories based on the specific allergic mediators they block:
I. Antihistamines—typically comprising first- and second-generation H1 receptor antagonists:
First-generation H1 receptor antagonists include chlorpheniramine, diphenhydramine, and promethazine; second-generation agents include astemizole, terfenadine, cetirizine, loratadine, and mizolastine; third-generation agents include desloratadine.
II. Serotonin antagonists, e.g., cyproheptadine.
III. Leukotriene receptor antagonists, e.g., montelukast sodium.
IV. Mast cell stabilizers (agents that inhibit the release of allergic mediators), e.g., ketotifen, tranilast, and doxepin. Other antiallergic agents include calcium preparations and histaglobulin. The above-listed drugs represent the most commonly used antiallergic agents in clinical practice; numerous additional agents exist but are not enumerated here.
