Qualified Medication Aides (QMA) Practice Exam

What is the primary action of an antihistamine?

1. Combat the effects of histamine during an allergic reaction

2. Increase histamine production in the body

3. Neutralize the effects of antihistamines in the body

4. Cause allergic reactions to subside

The correct answer is: Combat the effects of histamine during an allergic reaction

The primary action of an antihistamine is to combat the effects of histamine during an allergic reaction. Antihistamines work by blocking the action of histamine at the H1 receptor sites, which are responsible for the symptoms associated with allergic reactions, such as itching, sneezing, and swelling. By inhibiting histamine's effects, antihistamines can effectively reduce or alleviate the symptoms that arise from allergies, making them a vital medication in managing allergic responses. In contrast to the other choices, increasing histamine production is not a function of antihistamines; rather, they are designed to counteract its effects. The choice that mentions neutralizing the effects of antihistamines contradicts the function of these medications, as antihistamines themselves do not neutralize anything—rather, they prevent histamine from exerting its effects. Finally, while antihistamines can lead to a reduction in the symptoms of allergic reactions, they do not directly cause these reactions to subside; their mechanism is specifically aimed at blocking the receptor sites influenced by histamine.