Renal clearance of pentavalent antimony (sodium stibogluconate)

Kenyan kala-azar is sometimes unresponsive to a standard course of sodium stibogluconate. The renal excretion of sodium stibogluconate was therefore studied in patients with kala azar and in volunteers; both urine and serum levels of sodium stibogluconate were measured. After intravenous injection sodium stibogluconate seemed to be distributed throughout the extracellular fluid and to have a renal clearance similar to that of inulin. At 6 h blood levels had fallen to less than 1% of peak values. After intramuscular injection, peak blood levels were lower and more sustained. However, more than 80% was excreted in the first 6 h, and blood levels fell to around 1% of peak values in 16 h. The dangers of cumulative toxicity may be exaggerated, and restriction of courses of sodium stibogluconate to 30 days or even to 10 days (in the U.S.A.) may not be necessary. If shorter courses are ineffective prolonged and continued courses may be given provided that renal function is assessed and the dosage is adjusted when indicated.