An 83-year-old with Parkinson's disease needs an antiemetic to control nausea and vomiting. Which agent would be preferred?

An 83-year-old with Parkinson's disease needs an antiemetic to control nausea and vomiting. Which agent would be preferred?

• A. Domperidone
• B. Metoclopramide
• C. Prochlorperazine
• D. Ondansetron

Answer: (A)

In Parkinson’s disease, avoid antiemetics that block central dopamine D2 receptors because that can worsen motor symptoms. The best choice is an agent that works peripherally, providing antiemetic and prokinetic effects without significantly entering the brain. Domperidone fits this profile: it antagonizes D2 receptors in the gut and in the chemoreceptor trigger zone but has limited CNS penetration, so it controls nausea with a lower risk of aggravating Parkinsonian symptoms. Metoclopramide and prochlorperazine readily cross into the central nervous system and can worsen extrapyramidal features, making them less suitable in PD. Ondansetron acts on serotonin receptors and, while useful for nausea, does not provide the same prokinetic benefit and carries its own considerations in the elderly (such as QT prolongation risk).

In Parkinson’s disease, avoid antiemetics that block central dopamine D2 receptors because that can worsen motor symptoms. The best choice is an agent that works peripherally, providing antiemetic and prokinetic effects without significantly entering the brain. Domperidone fits this profile: it antagonizes D2 receptors in the gut and in the chemoreceptor trigger zone but has limited CNS penetration, so it controls nausea with a lower risk of aggravating Parkinsonian symptoms.

Metoclopramide and prochlorperazine readily cross into the central nervous system and can worsen extrapyramidal features, making them less suitable in PD. Ondansetron acts on serotonin receptors and, while useful for nausea, does not provide the same prokinetic benefit and carries its own considerations in the elderly (such as QT prolongation risk).