of chemotherapy induced nausea/vomiting (CINV), an indication for which it was previously FDA-approved. ECG interval changes including QT, QRS, and PR interval prolongation have been noted during clinical eva luation of IV dolasetron. Torsade de pointes has also been reported in some patients receiving dolasetron injection. Dolasetron injection can continue to be used for post-operative nausea and vomiting (PONV), since the lower doses used in PONV are less likely to affect the electrical activity of the heart. In addition, oral formulations of dolasetron will continue to carry indications for the prevention of CINV, since the oral form is associated with a smaller risk of developing an abnormal heart rhythm as compared with the parenteral form. Associated changes to cardiac electrical activity are related in magnitude and frequency to blood concentrations of the active metabolite (hydrodolasetron) and are self-limiting with declining blood concentrations. Some patients have interval prolongations for 24 hours or longer. Interval prolongation may lead to cardiovascular consequences, including heart block or cardiac arrhythmias; these have rarely been reported. Dolasetron should be avoided in patients with congenital long QT syndrome, hypokalemia or hypomagnesemia. Before initiating dolasetron therapy, hypokalemia and hypomagnesemia should be corrected. Electrolytes should be monitored as clinically indicated thereafter. In addition, dolasetron should be avoided in patients with complete heart block or at risk for complete heart block, unless they have an implanted pacemaker. Dolasetron should be administered with caution in patients with underlying structural heart disease or in patients who have or may develop prolongation of cardiac conduction intervals, particularly QT prolongation. Patients who may be at risk include patients on diuretic therapy with potential for inducing electrolyte imbalance, sick sinus syndrome, bradycardia, atrial fibrillation with slow ventricular response, myocardial ischemia, those taking anti-arrhythmic drugs or other drugs which lead to QT prolongation, those with pre-existing cardiac disease including congestive heart failure, elderly patients > 65 years of age, patients with renal impairment, and those who have received high cumulative doses of anthracyclines. An electrocardiogram (ECG) is warranted for at risk patients receiving dolasetron. Use dolasetron with caution in patients with other conditions that may increase the risk of QT prolongation including cardiac arrhythmias, heart failure, bradycardia, myocardial infarction, hypertension, coronary artery disease, hypocalcemia, or in patients receiving medications known to cause electrolyte imbalances. Females, patients with diabetes mellitus, thyroid disease, malnutrition, alcoholism, or hepatic disease may also be at increased risk for QT prolongation. Patients experiencing signs and symptoms of an abnormal heart rate or rhythm while taking dolasetron should be advised to contact their healthcare provider; clinicians are encouraged to report related adverse events to the FDA MedWatch program.
Children, infants, neonates
Dolasetron has been used in children age 2 to 16 years and has, overall, has been well tolerated. However, dolasetron should be used cautiously in pediatric patients who have preexisting, or are at risk of developing, prolonged cardiac conduction intervals, particularly QTc. Rarely, cases of sustained supraventr |
