Absorption of ipecac alkaloids in emergency patients.

Syrup of ipecac contains the nauseant alkaloids emetine and cephaeline. Although thousands of doses are given yearly, no data exist on the absorption of these alkaloids in man. We gave 30 mL of USP Syrup to ten adult patients. Blood and urine samples were obtained at approximately one-half and two hours after administration, and the entire volume of vomitus was saved. The samples were then analyzed for cephaeline and emetine by a high-performance liquid chromatographic (HPLC) assay developed in our laboratory. All patients vomited within 30 minutes, but the amounts of alkaloid regurgitated varied from 22 +/- 14% in six patients to 80 +/- 16% in the remaining four. Only six patients had emetine or cephaeline in their blood by two hours (range, 5 to 73 ng/mL), although ten patients had detectable concentrations of the alkaloids in their urine. Measured over two hours, no patient eliminated more than 0.5% of the dose by the urinary route. In our study ipecac was absorbed by all who received it; the extent of absorption varied widely, and elimination by the renal route was small.