Pharmacokinetics of ergotamine in healthy volunteers following oral and rectal dosing.

Twenty-four healthy volunteers participated in a study on the disposition of ergotamine following oral and rectal administration. Plasma samples were collected surrounding each dose of medication and a new mass spectrometry method was used for quantitation of the samples. A mean peak plasma concentration of 454 pg/ml was measured an average of 50 min following a 2 mg rectal dose. In contrast, the 2 mg oral dose produced a mean peak plasma concentration of 21 pg/ml an average of 69 min following the dose. Area under the concentration time curve indicated a relative bioavailability of 5% for the oral dosage form. Conflicting data on ergotamine disposition highlight the factors which may be responsible for determining bioavailability and pharmacologic activities of the compound.