Free Access
Issue
Vet. Res.
Volume 34, Number 4, July-August 2003
Page(s) 445 - 460
DOI https://doi.org/10.1051/vetres:2003014
How to cite this article Vet. Res. (2003) 445-460
Vet. Res. 34 (2003) 445-460
DOI: 10.1051/vetres:2003014

A pharmacokinetic model to document the actual disposition of topical ivermectin in cattle

Céline M. Laffonta, b, Alain Bousquet-Méloua, David Braleta, Michel Alvineriec, Johanna Fink-Gremmelsb and Pierre-Louis Toutaina

a  UMR 181 de Physiopathologie et Toxicologie Expérimentales INRA/ENVT, École Nationale Vétérinaire de Toulouse, 23 Chemin des Capelles, 31076 Toulouse Cedex 03, France
b  Department of Veterinary Pharmacy, Pharmacology and Toxicology, Utrecht University, Yalelaan 16, PO Box 80152, 3508 TD Utrecht, The Netherlands
c  Institut National de la Recherche Agronomique, Station de Pharmacologie et Toxicologie, 180 chemin de Tournefeuille, 31931 Toulouse Cedex, France

(Received 19 December 2002, accepted 25 March 2003)

Abstract
Ivermectin is a worldwide-used antiparasitic drug largely administered to cattle as a topical formulation (pour-on). The actual plasma and faecal disposition of pour-on ivermectin in cattle was documented using an original pharmacokinetic model, and taking into account the oral ingestion of the topical drug following physiological licking as a secondary route of exposure. Six pairs of monozygotic twin cattle received successively one i.v. and two pour-on administrations of ivermectin at a 3-5-month interval. For one pour-on administration, the twins were separated into an unrestrained group and a group where self- and allo-licking were prevented. Ivermectin concentrations in the plasma and faeces were determined by HPLC. Licking resulted in a high intra-and inter-individual variability of systemic exposure after topical application. By the means of pharmacokinetic modelling, we showed that 58-87% of the pour-on dose was ingested, while only 10% was absorbed percutaneously. Approximately 72% of the ingested ivermectin transited directly into the faeces, resulting in a 7-fold higher faecal excretion of the parent drug than in the non-lickers. We conclude that topical administration does not guarantee a controlled drug delivery in cattle. More importantly, the simulations revealed that non-treated cattle could get easily contaminated by allo-licking, raising the public health problem of unexpected drug residues in edible tissues.


Key words: ivermectin / pour-on / cattle / licking behaviour / pharmacokinetics

Correspondence and reprints: Alain Bousquet-Mélou Tel.: (33) 561 193 925; fax: (33) 561 193 917;
    e-mail: a.bousquet-melou@envt.fr

© INRA, EDP Sciences 2003

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.