The effect of
oral administration of
activated charcoal on total body clearance of
gentamicin administered intravenously (2 mg kg-1) has been studied in normal rabbits and rabbits with induced
renal failure. Gastric intubation of a single dose (10 g) of
activated charcoal to normal rabbits produced a significant reduction in
gentamicin serum concentrations compared to control. Significant differences between treated and control groups, compatible with enhancement of
gentamicin elimination, were observed in the calculated pharmacokinetic parameters (Kel, t 1/2, CL and AUC). To examine whether
renal failure could augment the effect of
activated charcoal in enhancing the systemic clearance of
gentamicin,
uranyl nitrate was used (0.75 mg kg-1, i.v.) to induce
acute renal failure in rabbits. The derived pharmacokinetic parameters of
gentamicin during the control phase in these animals were consistent with severe
renal failure. The administration of
activated charcoal, 2.5 h following
gentamicin injection, produced a steeper decline in
gentamicin concentration-time profiles and significant changes in Kel, t 1/2 and CL. The Kel and CL values increased to about 200%, while the t 1/2 value decreased to about 50%. The apparent changes in the pharmacokinetic parameters induced by
charcoal administration were more marked in rabbits with
renal failure than in normal rabbits; however, induction of
renal failure did not augment the
charcoal-induced clearance of
gentamicin quantitatively.