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Pharmacokinetics and milk residues of butorphanol in dairy cows after single intravenous administration
Author(s) -
COURT M. H.,
DODMAN N. H.,
LEVINE H. D.,
RICHEY M. T.,
LEE J. W.,
HUSTEAD D. R.
Publication year - 1992
Publication title -
journal of veterinary pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.527
H-Index - 60
eISSN - 1365-2885
pISSN - 0140-7783
DOI - 10.1111/j.1365-2885.1992.tb00983.x
Subject(s) - butorphanol , pharmacokinetics , pharmacodynamics , volume of distribution , zoology , chemistry , pharmacology , distribution (mathematics) , medicine , biology , mathematics , mathematical analysis
The pharmacokinetics of butorphanol tartrate were investigated following intravenous administration of 0.25 mg/kg of body weight to six healthy non‐lactating Jersey cows. Three lactating Holstein cows also received 0.045 mg of butorphanol/kg of body weight intravenously to determine the extent and duration of drug transfer into milk. A radioimmunoassay technique was used to measure butorphanol concentrations in plasma and milk. The disposition of butorphanol following intravenous administration was characterized by rapid and extensive distribution followed by a slower elimination phase. Apparent volume of distribution was 4.178 ± 1.145 (mean ± SD) I/kg, mean elimination half‐life was 82 min, and clearance was 34.6 ± 7.7 ml/min/kg. Trace quantities of butorphanol were detected in the cow's milk for up to 36 h following administration. These pharmacokinetic data were compared with pharmaco‐kinetic and pharmacodynamic data for butorphanol in other species and for three other potent opioids in related ruminant species.