Hemodialysis clearance of chloroquine in uremic patients.

The hemodialysis blood clearance of chloroquine was studied in four patients with chronic renal failure undergoing chronic hemodialysis. The patients were administered chloroquine (600 mg base) orally after a light breakfast. Blood samples were then obtained from arterial blood entering and venous blood leaving the dialysis machine at 0.0, 0.5, 1.0, 2.0, 4.0, and 6.0 h, and at 24.0 and 48.0 h post dialysis. The blood flow rate varied between 200 and 275 ml/min, while the dialysate flow rate was maintained at 500 ml/min. The samples were analyzed for chloroquine by high pressure liquid chromatography, and the dialysis clearance was calculated utilizing the formula: ClD = QB[(CA - CV)/CA]. The mean extraction ratios for chloroquine were 0.238, 0.317, 0.207, and 0.216 in the four patients during the 6-h dialysis period. The calculated dialysis clearances were 57.2, 77.0, 56.1, and 48.3 ml/min. Chloroquine hemodialysis clearance was 14.5% of total body clearance in normal subjects and in patients with chronic renal failure not on hemodialysis.