Efficacy of ipecac during the first hour after drug ingestion in human volunteers

Objective: To determine the decrease of drug absorption when syrup of ipecac is administered at various times within one hour of drug ingestion. Methods: Ten healthy human volunteers were recruited for a four-limbed randomized crossover study. The three experimental limbs consisted of administration of 30 mt syrup of ipecac, at 5, 30, or 60 minutes after ingestion of 3900 mg acetaminophen as 12 x 325 mg tablets with 250 mt room temperature water. The fourth limb served as control. Blood samples were drawn at 0, 0.5, 1.0, 2.0, 3.0, 4.0, 6.0, and 8.0 hours after analgesic ingestion for serum acetaminophen concentration determination by high-performance liquid chromatography. Repeated measures ANOVA and Tukey's HSD tests were used for group comparisons. Results: The area under the serum concentration vs time curve was (mean +/- SD) 206 +/- 48, 67 +/- 37, 183 +/- 78, and 162 +/- 47 mg/L for control, 5, 30, and 60 minutes, respectively. This corresponds to decreases in bioavailability of 67, 11, and 21%. Only the 5-minunte group differed significantly from control (p < 0.05). Sedation was observed as a significant adverse effect of ipecac administration. Conclusions: Our data do not support benefit from ipecac administration at 30 minutes and beyond. Our data suggest that benefit is lost at some point between 5 and 30 minutes. The sedative effect of ipecac may confound the observation of patients who have ingested sedative hypnotic agents.