Drug adsorption efficacy and palatability of a novel charcoal cookie formulation

To determine the effect of a novel charcoal cookie formulation compared with a standard aqueous charcoal product on the absorption of orally administered cimetidine, and to compare the palatability of the two charcoal products.

Prospective, open-label, three-way, crossover trial.

General clinical research center.

Eight healthy volunteers (five men, three women; mean age 23.4 yrs).

After an overnight fast, each subject ingested a single cimetidine 800-mg tablet. Fifteen minutes later, subjects were randomly assigned to receive either water (control), three charcoal cookies (equivalent to 7.2 g of charcoal), or 7.2 g of aqueous activated charcoal suspension. Subjects then received each of the other study treatments-cimetidine with water, cimetidine with charcoal cookies, and cimetidine with charcoal suspension-separated by a 1-week washout period between each treatment.

Venous blood samples were obtained before and 8 hours after administration of the cimetidine dose. Noncompartmental pharmacokinetic analysis was performed, and area under the plasma concentration-time curve (AUC) and maximum plasma concentration (C(max)) were compared for each study drug combination. In addition, subjects evaluated the palatability of each charcoal product by using a visual analog scale. Both charcoal products effectively adsorbed cimetidine, resulting in decreased absorption of most of the cimetidine dose. No significant difference was noted in the median percent decrease in cimetidine AUC between the charcoal suspension and charcoal cookie (91.8% vs 82.1%, p=0.505). Similarly, no significant difference was noted in the median percent decrease in C(max) between the two charcoal formulations (82.6% vs 64.0%, p=0.574). The palatability scores, however, were significantly higher for the charcoal cookie than for the charcoal suspension. All study drugs were well tolerated, and no adverse events were reported.

The new charcoal cookie formulation appears to be as effective as the aqueous charcoal suspension at reducing absorption of cimetidine. In addition, the charcoal cookie was rated as more palatable than the aqueous charcoal suspension, suggesting that the charcoal cookie could be an attractive alternative to the charcoal slurry for managing drug overdoses.