A patient is nauseated after Ketamine administration. Which antiemetic and dose is appropriate?

• A. Phenergan 12.5 mg
• B. Zofran 4 mg
• C. Promethazine 25 mg
• D. Dimenhydrinate 50 mg

Answer: (A)

Ketamine can trigger nausea and vomiting, so you want an antiemetic that works reliably and safely in the field. Phenergan (promethazine) at 12.5 mg provides solid antiemetic effect with the added benefit of mild sedation, which can help the patient cope with nausea and distress after ketamine. The 12.5 mg dose strikes a balance between efficacy and the risk of side effects like excessive sedation, hypotension, or extrapyramidal symptoms that can come with a higher dose. While other antiemetics like ondansetron (Zofran) are effective, promethazine is a practical, readily available choice for this scenario, and a higher promethazine dose (25 mg) increases risk without a clear additional benefit in this context. Dimenhydrinate is less potent for acute vomiting control here. Therefore, Phenergan 12.5 mg is the most appropriate option.