Acceleration of the Body Clearance of Phenobarbital by Oral Activated Charcoal

Abstract

We investigated the effect of multiple oral doses of activated charcoal on the pharmacokinetics of intravenously administered phenobarbital in a randomized crossover trial. Six healthy men volunteered to take 200 mg of phenobarbital sodium per 70 kg of body weight intravenously on two separate occasions. On one occasion, each subject received oral activated charcoal (180 g) in divided doses over three days after the infusion of phenobarbital. Serum levels of phenobarbital were measured in all subjects up to 96 hours after the infusion, and urinary excretion of phenobarbital was measured in two subjects 24 to 96 hours after the infusion. A pharmacokinetic analysis showed that the charcoal decreased the serum half-life of phenobarbital form 110 +/- 8 to 45 +/- 6 hours (S.E.M.) (P less than 0.01), increased the total body clearance of phenobarbital from 4.4 +/- 0.2 to 12.0 +/- 1.6 ml per kilogram per hour (P less than 0.01), and increased the nonrenal clearance from 52 to 80 per cent of the total body clearance. We conclude that oral administration of activated charcoal enhances the nonrenal clearance of phenobarbital.

Effect of oral activated charcoal on tobramycin clearance

“…Recent literature indicates that activated charcoal administered orally or by nasogastric tube can enhance the clearance of intravenously administered drugs, such as phenobarbital, digitoxin, methotrexate, and other agents (1,2,4,7,9,12,13). However, activated charcoal is not without risk.…”

“…The small changes noted may have been due to a decrease in glomerular filtration caused by volume contraction from the cathartics. Oral activated charcoal has been shown to enhance the elimination of other drugs from the body, including agents that do not undergo enterohepatic recycling, such as theophylline (1,2,4,7,9,12,13). The increase in drug clearance results from the adsorption of the drug onto the charcoal after diffusion into the gastrointestinal lumen from the circulation (10,14).…”

Transport of phenobarbitone into the intestinal lumen and the biliary tract following i.v. administration to rats

“…The clearance of intravenously administered phenobarbitone (Berg et al 1982) Yamamoto et a1 1984), few have aimed at the application of intestinal dialysis to the treatment of drug poisoning. Phenobarbitone remains an important drug in clinical toxicology, and if its enteral secretion and reabsorption are extensive, interruption of this circulation by adsorbents such as activated charcoal may increase the rate of its elimination.…”

Adsorption Studies of Artesunate: Evaluation of Saline Cathartics as Additive in Management of Artesunate Poisoning.

“…It has been of immense value to administer saline cathartics; with adsorbent to prevent constipation or impaction. [7][8][9] There are currently no documented information on antidotes for the management of artesunate poisoning hence in the present study, AC was evaluated as possible antidotes for the management of artesunate overdose and or poisoning.…”