Division of Field Epidemiology and Division of Surveillance and Epidemiology, Epidemiology Program Office, and Division of Parasitic Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Communicable Disease Control Section, North Carolina Department of Environment, Health, and Natural Resources, Atlanta, Georgia
The antimalarial drug halofantrine hydrochloride has been associated with cardiac arrhythmias. This is a report of a study on the cardiac effects of standard-dose halofantrine (24 mg/kg) on a sample of 48 patients selected from a group of 402 Dega (Montagnard) refugees treated for Plasmodium falciparum infection. Prolongation of the rate-corrected QT interval (QTc) on the electrocardiogram (ECG) was used as an indicator of risk for halofantrine-associated cardiac arrhythmias. We found that standard-dose halofantrine was associated with a lengthening of the mean QTc from 0.40 sec1/2 to 0.44 sec1/2. Two patients had a QTc increase of greater than 25%, but none had a follow-up QTc of more than 0.55 sec1/2, an interval length generally considered to be a risk factor for ventricular arrhythmias. Regression analysis indicated that pretreatment ECGs were poorly predictive of QTc lengthening during therapy, although pretreatment ECGs may be useful to evaluate patients with pre-existing cardiac conditions. The manufacturer has recommended that the halofantrine dose not exceed 24 mg/kg and revised the list of medication contraindications to include some cardiac conditions. Clinicians should weigh a patient's risk, including history of cardiac disease and availability of alternative therapy, before use of halofantrine.