Activated charcoal and syrup of ipecac in prevention of cimetidine and pindolol absorption in man after administration of metoclopramide as an antiemetic agent.

The effects of activated charcoal and ipecac syrup by mouth on cimetidine and pindolol absorption were studied in seven subjects, who had ingested 20 mg metoclopramide 1 h earlier, and compared with the adsorption capacity of charcoal in vitro. Activated charcoal, 50 g, given 5 min after 400 mg cimetidine + 10 mg pindolol, reduced their absorption by 99% or more, based on AUC0-48h and the 48-h urinary excretion of the drugs. Syrup of ipecac caused emesis on each occasion. On the average, ipecac reduced the absorption of cimetidine and pindolol by 75% and 60%, respectively. Based on studies in vitro it seems probable that the adsorbing capacity of charcoal for cimetidine but not for pindolol will be saturated if 50 g charcoal is given after an overdose of about 100 fold the therapeutic dose. Because the use of ipecac allowed an absorption of the drugs at least 30 fold that allowed by charcoal, the immediate administration of activated charcoal, without preceding lavage or emesis, should be considered in such poisonings where the adsorption capacity of high charcoal doses will not be saturated.