1. Licking behaviour and environmental contamination arising from pour-on ivermectin for cattle
- Author
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Michel Alvinerie, Pierre-Louis Toutain, Alain Bousquet-Mélou, Céline M. Laffont, Physiologie et Toxicologie Expérimentales, Institut National de la Recherche Agronomique (INRA)-Ecole Nationale Vétérinaire de Toulouse (ENVT), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées, Laboratoire de Pharmacologie et Toxicologie, Institut National de la Recherche Agronomique (INRA), and Bousquet-Mélou, Alain
- Subjects
Administration, Topical ,Helminthiasis ,Drug resistance ,Pharmacology ,030308 mycology & parasitology ,0403 veterinary science ,Feces ,Ivermectin ,Blood plasma ,MESH: Behavior, Animal ,MESH: Cattle Diseases ,MESH: Animals ,Anthelmintic ,media_common ,2. Zero hunger ,Anthelmintics ,0303 health sciences ,Behavior, Animal ,Ecology ,MESH: Feces ,04 agricultural and veterinary sciences ,3. Good health ,MESH: Administration, Topical ,MESH: Helminthiasis ,MESH: Cattle ,Infectious Diseases ,MESH: Anthelmintics ,Topical ,[SDV.SP.PHARMA] Life Sciences [q-bio]/Pharmaceutical sciences/Pharmacology ,Area Under Curve ,Toxicity ,Administration ,Injections, Intravenous ,Intravenous ,medicine.drug ,MESH: Half-Life ,Half-Life ,Drug ,MESH: Ecology ,040301 veterinary sciences ,media_common.quotation_subject ,Cattle Diseases ,Biology ,MESH: Ivermectin ,Injections ,03 medical and health sciences ,medicine ,Animals ,Behavior ,Animal ,MESH: Injections, Intravenous ,[SDV.SP.PHARMA]Life Sciences [q-bio]/Pharmaceutical sciences/Pharmacology ,MESH: Area Under Curve ,Parasitology ,Cattle ,Licking - Abstract
International audience; Pour-on formulations of endectocides are extensively used to treat and control systemic parasitic diseases in cattle, worldwide. The purpose of the present study was to investigate the influence of the natural licking behaviour of cattle on the plasma and faecal disposition of topically administered ivermectin. Twelve Holstein cattle were given one single intravenous (i.v.) (200 microg/kg) and topical (500 microg/kg) administration of ivermectin at a 5-month interval. For the pour-on administration, the animals were allocated into two groups (n=6): one control group (lickers) and one group where licking was prevented (non-lickers). Ivermectin plasma (total) clearance (270+/-57.4 ml/kg/day) was very homogeneous among the 12 cattle. In contrast, major differences between lickers and non-lickers were observed following pour-on administration. Prevention of licking resulted in an extended terminal plasma half-life (363+/-16.2 vs. 154+/-7.4 h in lickers) and in a lower and less variable systemic availability of ivermectin (19+/-4.9 vs. 33+/-18.5% in lickers). More importantly, nearly 70% of the pour-on dose was recovered as parent drug in the faeces of lickers vs. only 6.6% in non-lickers. Altogether, these results are consistent with an oral rather than percutaneous absorption of topical ivermectin in control animals, the non-systemically available fraction of ingested ivermectin providing a major contribution (80%) to the drug faecal output. The consequences of licking on the disposition of pour-on ivermectin are discussed in terms of environment, given the known ecotoxicity of this drug, and of cross-contamination. Animals licking themselves and each other could result in unexpected residues in edible tissues of untreated animals and in possible subtherapeutic drug concentrations, a factor in drug resistance. According to the Precautionary Principle, these considerations elicit concern over the use of topical drug formulations in cattle.
- Published
- 2001