Certified Neuroscience Registered Nurse (CNRN) Practice Exam

Which of the following medications is an example of an H1 antagonist used for PONV?

1. Dramamine

2. Scopolamine

3. Midazolam

4. Atropine

The correct answer is: Dramamine

Dramamine, known generically as dimenhydrinate, is indeed an H1 antagonist commonly used to prevent and treat nausea and vomiting, including postoperative nausea and vomiting (PONV). H1 antagonists work by blocking the action of histamine at the H1 receptor sites, which are involved in the regulation of the body's vestibular system and the central vomiting pathways in the brain. This action helps to alleviate symptoms of motion sickness and nausea. In contrast, Scopolamine is an anticholinergic medication that is primarily utilized for motion sickness and to prevent PONV as well but does not act as an H1 antagonist. Midazolam is a benzodiazepine that serves primarily as an anxiolytic and sedative, while Atropine is also an anticholinergic medication mainly used to increase heart rate or limit secretions, not specifically targeting nausea and vomiting pathways. Thus, Dramamine stands out as the appropriate choice for its specific action as an H1 antagonist in the context of preventing PONV.