Studies of meclofenamic acid and two metabolites in horses--pharmacokinetics and effects on exercise tolerance.
The pharmacokinetics and the effects on treadmill exercise of the anti-inflammatory drug meclofenamic acid were studied in seven Standardbred horses after single intravenous and/or oral doses. The decline in plasma concentration after a single intravenous dose of meclofenamic acid (2.2 mg/kg b.wt) was described by a two-compartment open model. The average elimination half-life was 1.4 h, the apparent volume of distribution 0.14 l/kg and the plasma clearance 0.12 l/h kg. Absorption was the rate-limiting step after oral administration. Non-compartmental analysis showed a mean absorption time of 4.3 h. The pharmacokinetics of two metabolites of meclofenamic acid were also studied in two of the horses. The elimination half-lives of the two metabolites were virtually the same in each horse (3.0 h and 3.4 h). The blood lactate response to exercise was significantly decreased after treatment with meclofenamic acid, indicating a lower utilization of the glycolytic ('anaerobic') energy contribution during exercise. Circulatory capacity was apparently unaffected with an unchanged heart rate response to exercise.
Johansson
I M
IM
University of Uppsala, Equine Drug Research Laboratory, Sweden.
Kallings
P
P
Hammarlund-Udenaes
M
M
D000042:Absorption; D000284:Administration, Oral; D000818:Animals; D001682:Biological Availability; D005080:Exercise Test / Q000662:veterinary; D005260:Female; D006207:Half-Life; D006339:Heart Rate / Q000187:drug effects; D006736:Horses / Q000378:metabolism / Q000502:physiology*; D007275:Injections, Intravenous / Q000662:veterinary; D007773:Lactates / Q000097:blood; D008297:Male; D008469:Meclofenamic Acid / Q000008:administration & dosage / Q000493:pharmacokinetics* / Q000494:pharmacology; D005082:Physical Exertion / Q000187:drug effects*; D014018:Tissue Distribution
D007773:Lactates; D008469:Meclofenamic Acid