Effect of orally administered activated charcoal on vancomycin clearance

Vancomycin is a narrow-spectrum antibiotic that has concentration-dependent efficacy and toxicity. Recent literature indicates that orally administered activated charcoal can enhance the clearance of intravenously administered drugs. To evaluate the effects of activated charcoal on vancomycin clearance, six healthy male volunteers received vancomycin (1 g) intravenously with and without activated charcoal coadministration. In a randomized crossover sequence, subjects were given 50 g of activated charcoal immediately before the vancomycin infusion was begun and 15 g at 2, 4, 6, and 8 h afterwards, or an equal volume of water. Multiple doses of charcoal did not have a statistically significant effect on any pharmacokinetic parameter for vancomycin. Mean control values +/- standard deviation for vancomycin clearance, elimination half-life, and 24-h urinary recovery were 6.4 +/- 1.0 liters/h, 6.6 +/- 1.5 h, and 856 +/- 116 mg, respectively. Mean values for the same parameters were 6.4 +/- 1.0 liters/h, 6.0 +/- 0.9 h, and 897 +/- 130 mg when activated charcoal was given. We conclude that multiple doses of orally administered activated charcoal do not enhance vancomycin clearance in subjects with normal renal function when serum concentrations are within the therapeutic range. The results of this investigation cannot be extrapolated to patients with toxic vancomycin concentrations or renal dysfunction. The use of activated charcoal in these populations warrants further study.