Pheniramine Maleate

**Semantic type:** Organic Chemical|Pharmacologic Substance

**Definition:** The maleate salt form of pheniramine, an alkylamine derivative with antihistaminic and vasodilatory properties. Pheniramine maleate binds to histamine H1 receptors, thereby inhibiting phospholipase A2 and production of endothelium-derived relaxing factor, nitric oxide. Subsequent lack of activation of guanylyl cyclase through nitric oxide results in decreased cyclic GMP (cGMP) levels, thereby inhibiting constriction of smooth muscle tissue, and decreased capillary permeability and histamine-activated allergic reactions.

**Synonyms:** - PHENIRAMINE MALEATE