What adverse effects should be monitored for antiemetics like ondansetron?

• A. QT prolongation and headaches or dizziness
• B. Hypotension and tachycardia
• C. Hyperglycemia
• D. Ototoxicity

Answer: (A)

Ondansetron and similar antiemetics work by blocking 5-HT3 receptors, which helps prevent nausea and vomiting, but they can affect cardiac repolarization. The main safety concern to monitor is QT interval prolongation, which under certain conditions can lead to dangerous ventricular arrhythmias like torsades de pointes. This risk is higher with higher IV doses, electrolyte disturbances (low potassium or magnesium), and when combined with other drugs that prolong the QT interval. In addition, headaches and dizziness are common, nonspecific adverse effects that patients often report and that clinicians monitor. Other listed effects like hyperglycemia or ototoxicity aren’t characteristic risks of this class, so they’re not the focus of routine monitoring.