Which antiemetic dose is used for adult abdominal pain?

• A. Zofran 4 mg IV/IO/IM
• B. Zofran 8 mg IV/IO/IM
• C. Zofran 2 mg IV/IO/IM
• D. Zofran 6 mg IV/IO/IM

Answer: (A)

Ondansetron works by blocking serotonin receptors in areas of the body involved in nausea and vomiting, making it a first-line antiemetic for adults with abdominal pain when vomiting is a concern. The standard initial dose is 4 mg given IV, IO, or IM because this amount provides reliable, rapid relief with a favorable safety profile in adults. If symptoms persist, a second 4 mg dose can be given, but the total should not exceed 8 mg per dosing period, which keeps the risk of side effects, including rare QT prolongation, low. The 4 mg dose is favored because it balances quick onset and effectiveness with safety across typical prehospital and emergency settings, whereas higher single doses offer diminishing returns and greater risk, and lower doses may be less consistently effective.