Loratadine works by selectively blocking H1 receptors. These receptors are found throughout the body, but are particularly relevant in allergic reactions. When an allergen triggers a response, histamine binds to these H1 receptors, causing the symptoms of allergies like sneezing, itching, and runny nose. Loratadine prevents histamine from binding, thus reducing these symptoms.
Specifically, loratadine is a competitive antagonist. This means it competes with histamine for binding sites on the H1 receptors. Because loratadine has a higher affinity for these receptors than histamine at therapeutic doses, it effectively displaces histamine and blocks its action.
This competitive antagonism explains loratadine’s effectiveness in treating allergic rhinitis (hay fever) and urticaria (hives). The medication’s impact on H1 receptors leads to a reduction in inflammatory responses, providing relief from allergy symptoms. Its selectivity means it primarily affects H1 receptors, minimizing the risk of side effects associated with other types of antihistamines that interact with other receptors.
Remember to consult your doctor or pharmacist for personalized advice regarding Loratadine use.
