Pharmacokinetics of cisapride in horses after intravenous and rectal administration
Cook, G.; Papich, M.G.; Roberts, M.C.; Bowman, K.F.
American Journal of Veterinary Research 58(12): 1427-1430
1997
ISSN/ISBN: 0002-9645 PMID: 9401693 Document Number: 476126
Objectives: To determine the IV pharmacokinetics of cisapride and measure systemic absorption after rectal administration. Animals: 5 healthy adult mares (380 to 610 kg). Procedure: Cisapride was administered, IV, at a dosage of 0.1 mg/kg of body weight. In the same horses, after a 1-week washout period, cisapride was administered rectally at a dosage of 1 mg/kg by mixing crushed tablets with propylene glycol and administering the mixture into the rectum. After each drug administration, a series of blood samples were collected. Plasma was obtained and analyzed by high-performance liquid chromatography to determine cisapride concentration profiles after each drug administration. Results: After IV administration, peak plasma concentration was 221.4 ng/ml and harmonic mean half-life was 1.9 hours. Rectal absorption of cisapride was negligible. Cisapride was detected in plasma from only 3 of 5 horses for which mean systemic availability was 1.23%. Mean maximal plasma concentration after rectal administration of cisapride was 13.5 ng/ml. Conclusion and Clinical Relevance: After IV administration of cisapride, plasma concentration is high for approximately 2 hours. Cisapride mixed with propylene glycol and administered rectally at a dosage of 1 mg/kg is poorly and incompletely absorbed. Thus, cisapride is not clinically useful for rectal administration in horses.