THE EFFECT OF ACTIVATED-CHARCOAL ON PHENYTOIN PHARMACOKINETICS

Study objectives: To examine the effect of administration of oral activated charcoal with or without sorbitol on the elimination of phenytoin. Setting: Emergency department of a rural teaching institution. Type of participants: Eight normal volunteers. Interventions: Subjects received 15 mg/kg phenytoin as an IV infusion. During the first phase of the study, oral activated charcoal was administered to a total dose of 140 g over a ten-hour period. During the second phase of the study, phenytoin alone was administered. Measurements and main results: Administration of activated charcoal resulted in a significant decrease in the area under the curve 0-inf (P = .008) and in total body clearance (P = .008). No difference in the effect on phenytoin pharmacokinetic parameters was noted when the charcoal was administered with or without sorbitol, but fewer gastrointestinal adverse effects were noted without sorbitol treatment. Conclusion: Oral activated charcoal was shown to affect phenytoin pharmacokinetic parameters. Further pharmacokinetic/pharmacodynamic studies are warranted to determine if activated charcoal results in a faster recovery from phenytoin toxicity. © 1990 American College of Emergency Physicians.