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Plasma concentrations of flunixin in the horse: its relationship to thromboxane B 2 production
Author(s) -
SOMA L. R.,
UBOH C. E.,
RUDY J.,
FEGELY J.
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.tb01019.x
Subject(s) - horse , thromboxane , medicine , zoology , thromboxane b2 , significant difference , endocrinology , platelet , biology , paleontology
The effects of the intravenous (i.v.) administration of 1.1 mg/kg of flunixin meglumine on thromboxane B 2 (TxB 2 ) concentrations were studied in sedentary and 2‐year‐old horses in training. The baseline TxB 2 serum concentrations generated during clotting were 2.89 ± 81, 2.19 ± 0.25 and 0.88 ± 0.12 ng/ml for the 2‐year‐old Thoroughbreds in training, sedentary horses under 10 and over 10 years old, respectively. There was a significant difference in baseline TxB 2 concentrations between older and younger horses (P < 0.005). Significant reduction in TxB 2 production from baseline were noted at 1 (P < 0.01) and 4 h (P < 0.01) but not at 8 h after flunixin administration. The percent reduction in serum TxB 2 concentration at 1 h after the administration of flunixin was 68.6 ± 7.8 and 45.2 ± 6.8 for the training and sedentary horses, respectively; the differences were significant (P < 0.04). Serum concentrations of TxB 2 returned to baseline values by 12–16 h after flunixin administration. The results of this study indicate a difference in the TxB 2 concentrations of older vs. younger horses and a difference in the suppression of TxB 2 after the administration of flunixin in 2‐year‐old Thoroughbreds in training compared to sedentary horses. The results of this study suggest that the detection of low concentrations of flunixin in urine 24 h post‐administration may not represent pharmacologic effective concentrations of flunixin in plasma.