Certification of Pharmacy Technicians (ExCPT) Practice Exam

Which drug class does Diphenhydramine belong to?

1. Antihistamine

2. Analgesic

3. Sequential therapy

4. Corticosteroid

The correct answer is: Antihistamine

Diphenhydramine is classified as an antihistamine, which is a type of medication that blocks the effects of histamine, a substance in the body that can cause allergic symptoms. Antihistamines like diphenhydramine are commonly used to relieve symptoms associated with allergies, such as sneezing, runny nose, and itchy or watery eyes. They can also be used as a sleep aid and for relief from motion sickness due to their sedative properties. Antihistamines work by binding to histamine receptors in the body, thereby preventing the action of histamine. This mechanism is particularly effective in managing allergic reactions and symptoms. The other drug classes do not accurately describe diphenhydramine. Analgesics are medications used to relieve pain, which is not the primary action of diphenhydramine. Sequential therapy refers to a treatment methodology rather than a drug class, often used in the context of treatment regimens for chronic diseases. Corticosteroids are steroid hormones that are used to reduce inflammation and suppress the immune response, which again does not encompass the properties of diphenhydramine. Thus, the identification of diphenhydramine as an antihistamine is clearly aligned with its pharmacological properties