Pharmacodynamic properties
Meloxicam is a non-steroidal anti-inflammatory drug (NSAID) of the oxicam class which acts by inhibition of prostaglandin synthesis, thereby exerting anti-inflammatory, anti-exudative, analgesic and antipyretic effects. It reduces leukocyte infiltration into the inflamed tissue. To a minor extent it also inhibits collagen-induced thrombocyte aggregation. Meloxicam also has anti-endotoxic properties because it has been shown to inhibit production of thromboxane B2 induced by E. coli endotoxin administration in calves and lactating cows.
Pharmacokinetic properties
Absorption: After a single subcutaneous dose of 0.5mg meloxicam/kg, Cmax values of 2.1μg/ml and 2.7μg/ml were reached after 7.7 hours and 4 hours in young cattle and lactating cows, respectively.
Distribution: More than 98% of meloxicam is bound to plasma proteins. The highest meloxicam concentrations are to be found in liver and kidney. Comparatively low concentrations are detectable in skeletal muscle and fat.
Metabolism: Meloxicam is predominately found in plasma. In cattle, meloxicam is also a major excretion product in milk and bile whereas urine contains only traces of the parent compound. Meloxicam is metabolised to an alcohol, an acid derivative and to several polar metabolites. All major metabolites have been shown to be pharmacologically inactive. The metabolism in horses has not been investigated.
Elimination: Meloxicam is eliminated with a half life of 26 hours and 17.5 hours after subcutaneous injection in young cattle and lactating cows, respectively. In horses, after intravenous injection meloxicam is eliminated with a terminal half-life of 8.5 hours. Approximately 50% of the administered dose is eliminated via urine and the remainder via faeces.