What are the different types of antiallergic drugs?
Antiallergic medications generally include antihistamines, leukotriene receptor antagonists, mast cell stabilizers, glucocorticoids, and calcium channel blockers. Patients should take medications strictly as prescribed by their physician. If any discomfort occurs, prompt medical consultation is advised.
1. Antihistamines
These are typically classified into first-generation and second-generation H1 receptor antagonists. First-generation agents include chlorpheniramine, diphenhydramine, and promethazine. Second-generation agents include astemizole, terfenadine, cetirizine, loratadine, and mizolastine. Third-generation agents include desloratadine.
2. Leukotriene Receptor Antagonists
Montelukast sodium—commonly available as tablets—is a selective leukotriene receptor antagonist that specifically inhibits the cysteinyl leukotriene receptor, thereby attenuating leukotriene-mediated inflammatory responses and allergic symptoms. Leukotrienes are key mediators in allergic and inflammatory reactions and play an important role in the pathogenesis of conditions such as asthma and allergic rhinitis.
3. Mast Cell Stabilizers
Sodium cromoglicate is a commonly used mast cell stabilizer, available in formulations such as ophthalmic solutions and capsules. It acts primarily by stabilizing mast cell membranes to prevent degranulation, thereby inhibiting the release of allergic mediators—including histamine and leukotrienes. Since it exerts no antagonistic effect on mediators already released, it must be administered prior to allergen exposure to effectively prevent allergic reactions.
4. Glucocorticoids
Glucocorticoids possess potent anti-inflammatory and antiallergic effects. They suppress the migration and activation of inflammatory cells, reduce the synthesis and release of inflammatory mediators, and modulate immune responses involved in allergic reactions. Commonly used agents include prednisone and methylprednisolone. However, long-term use may lead to numerous adverse effects, such as osteoporosis, hyperglycemia, and moon facies.
5. Calcium Channel Blockers
Some calcium channel blockers—such as calcium gluconate—inhibit the influx of calcium ions into mast cells, thereby reducing mast cell degranulation and subsequent release of allergic mediators. Additionally, they decrease capillary permeability, alleviating tissue edema and pruritus associated with allergic reactions.
In daily life, individuals should avoid contact with known allergens; otherwise, symptoms may worsen and cause discomfort. Common allergens include pollen, dust, foreign proteins, chemical substances, and ultraviolet radiation. Therefore, minimizing exposure to these triggers is essential to prevent recurrent allergic episodes.
