The effect of end-stage renal failure and haemodialysis on the elimination kinetics of sotalol.

A single oral dose of sotalol (160 mg) was administered to control subjects with normal renal function and patients with chronic renal failure in the interdialysis period to estimate the elimination kinetics of the drug. Sotalol concentrations in body fluids were measured fluorimetrically using a modified Garrett and Schnelle (1971) method. Mean plasma half-life (T 1/2) was approximately 5 h in normals, 42 h in patients off-dialysis. During haemodialysis the mean plasma half-time was on the average 7 hours. Comulative urinary excretion of the drug was considerably lower in the patient group: 9% of the dose in 48 h as opposed to 61% in normals. Comparison of sotalol concentrations in plasma versus ultrafiltrate from the coil kidney indicates that the drug in vivo is negligible bound to plasma proteins in remal patients. The net-lowering effect of a 6 to 7 h haemodialysis on the plasma concentration decay line was by 20%. Post-dialysis plasma concentration data suggest that the rate at which sotalol returns to plasma from body tissues appears to be the rate-controlling factor in the elimination of sotalol by haemodialysis.