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Pharmacokinetics and pharmacodynamics comparison between subcutaneous and intravenous butorphanol administration in horses
Author(s) -
Chiavaccini L.,
Claude A. K.,
Lee J. H.,
Ross M. K.,
Meyer R. E.,
Langston V. C.
Publication year - 2015
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/jvp.12191
Subject(s) - butorphanol , pharmacokinetics , bioavailability , crossover study , medicine , pharmacodynamics , volunteer , anesthesia , subcutaneous injection , pharmacology , alternative medicine , pathology , agronomy , biology , placebo
The study objective was to compare butorphanol pharmacokinetics and physiologic effects following intravenous and subcutaneous administration in horses. Ten adult horses received 0.1 mg/kg butorphanol by either intravenous or subcutaneous injections, in a randomized crossover design. Plasma concentrations of butorphanol were measured at predetermined time points using highly sensitive liquid chromatography–tandem mass spectrometry assay ( LC ‐ MS / MS ). Demeanor and physiologic variables were recorded. Data were analyzed with multivariate mixed‐effect model on ranks ( P ≤ 0.05). For subcutaneous injection, absorption half‐life and peak plasma concentration of butorphanol were 0.10 ± 0.07 h and 88 ± 37.4 ng/mL (mean ± SD ), respectively. Bioavailability was 87%. After intravenous injection, mean ± SD butorphanol steady‐state volume of distribution and clearance was 1.2 ± 0.96 L/kg and 0.65 ± 0.20 L/kg/h, respectively. Terminal half‐lives for butorphanol were 2.31 ± 1.74 h and 5.29 ± 1.72 h after intravenous and subcutaneous administrations. Subcutaneous butorphanol reached and maintained target plasma concentrations >10 ng/mL for 2 ± 0.87 h (Mean ± SD ), with less marked physiologic and behavioral effects compared to intravenous injection. Subcutaneous butorphanol administration is an acceptable alternative to the intravenous route in adult horses.