Electrocardiographic changes during treatment of leishmaniasis with pentavalent antimony (sodium stibogluconate)

Serial electrocardiograms (ECGs) were obtained during 65 courses of sodium stibogluconate treatment in 59 Kenyan patients with leishmaniasis (56 visceral and 3 cutaneous). ECG abnormalities developed during 54% of the treatment courses. The frequency with which abnormalities occurred was related to the total daily dose of antimony (Sb), increasing from 2/9 patients treated with 10 mg Sb/kg/d to 25/48 treated with 20-30 mg Sb/kg/d and 8/8 treated with 40-60 mg Sb/kg/d. The frequency with which ECG abnormalities developed was also related to the duration of treatment, increasing from 11/65 patients after 7 days to 18/44 after 15 days, 26/39 after 30 days and 11/12 after 60 days. ECG abnormalities were similar to those previously described during treatment with trivalent antimonial drugs, the most common being flattening and/or inversion of T waves. Prolongation of the corrected QT interval occurred in 13 patients, all of whom were treated for more than 30 days or with more than 20 mg Sb/kg/d. One patient died suddenly during the fourth week of treatment with 60 mg Sb/kg/d, and 2 patients died of measles after 9 or 10 days of treatment with 30 mg Sb/kg/d. QT prolongation and a concave ST segment developed in all 3 patients who died. We conclude that minor ECG abnormalities are common when sodium stibogluconate is used at doses above 20 mg Sb/kg/d for more than 15 days, and that life-threatening arrhythmias may occur if very high doses are used.