What is the mechanism of action of oral antihistamines?

The correct answer, blocking histamine receptors, highlights the primary mechanism through which oral antihistamines work to alleviate symptoms associated with allergic reactions. Oral antihistamines specifically target histamine H1 receptors. When histamine, a compound released during allergic responses, binds to these receptors, it can cause a range of symptoms such as itching, sneezing, and runny nose. By blocking these receptors, antihistamines effectively prevent or reduce these symptoms from occurring.

This is a key aspect of their function, particularly in treating allergic rhinitis and other conditions where histamine release is prevalent. The effectiveness of antihistamines in managing allergies is largely due to their ability to inhibit the action of histamine at the receptor level, preventing the cascade of allergic symptoms from developing.

Understanding the specific roles that histamine plays in the body enhances the comprehension of why targeting its receptors can be beneficial in controlling allergic reactions.