A 66-year-old woman presents for elective cholecystectomy. Her preoperative electrocardiogram is below.
Which of the following is the MOST appropriate prophylactic antiemetic?
Prolongation of the QT interval, as depicted in Figure 1, can be hereditary or acquired (medication related). Hereditary long QT syndrome is the result of a disorder of voltage-gated sodium channels. Medication-related QT prolongation may be associated with multiple classes of medications, including antibiotics, antiarrhythmics, antidepressants, and antiemetics. Prolongation of the QT interval leads to abnormal ventricular repolarization, triggering premature ventricular contractions. Premature ventricular contractions may then precipitate a reentrant ventricular arrhythmia or polymorphic ventricular tachycardia (torsades de pointes).
Perioperative management of patients with prolonged QT interval includes avoidance of medications that could worsen prolongation and lead to torsades de pointes. Many antiemetics are associated with an increase in QT interval. These include droperidol, promethazine, and 5-hydroxytryptamine (HT)3 blockers such as granisetron. Dexamethasone does not...