Meloxicam is an NSAID of the oxicam class that acts by inhibiting prostaglandin synthesis and inducible COX-2, thereby exerting antiinflammatory, anti-exudative, analgesic and antipyretic effects.The molecule is highly plasma protein bound, when circulating in the body (95-99%). It has a long plasma half-life, enabling less frequent dosage schemes.4,5,6
Compared to several other NSAID´s tested, meloxicam was shown to be the most selective inhibitor of inducible cyclo-oxygenase activity. Primary pharmacological effects include anti-inflammatory, anti-pyretic and analgesic properties in several species including humans, probably due to inhibition of inducible cyclo-oxygenase.7
Tissue reactions after a single subcutaneous injection of meloxicam was studied in rats. The tolerance after i.v., i.m., and s.c. injection and after dermal, rectal, and eye-drop application of a meloxicam formulation was also studied in several laboratory animals (rats, guinea pigs and rabbits). The total composition of the formulation used is not given, but it is stated that the formulation was one intended for human use. The conclusions reported from these study data indicated that the meloxicam injectable formulation was well tolerated.7
Its chemical name is 4-Hydroxy-2-methyl-N-(5-methyl-2-thiazolyl)-2H-1,2-benzothiazine-3-carboxamide-1,1-dioxide
The pharmacokinetic behavior of meloxicam after a single dose was elucidated in an intravenous pilot study in calves with radiolabelled meloxicam and in a bioavailability study in calves with administration of 0.5% injectable meloxicam solution via the IV and SC route in a cross-over design. The Cmax of meloxicam from the SC administration was reached after 6 to 8 hours. The absolute availability was variable with values ranging from 44 to 154 % in individual animals. The mean elimination half-life of meloxicam from plasma was approximately 26 hours irrespective of the route of administration. Elimination of total radioactivity from plasma exhibited a terminal half-life of approximately 24 hours. Plasma protein binding ex vivo was found to be > 96.5 % and the same degree of binding was found in vitro.
At all sacrifice time points investigated in the pilot study, the liver contained the highest concentration followed by the kidney and bile. Comparatively low concentrations were found in skeletal muscle and fat. The proportions of radioactivity excreted in the urine and the feces were approximately equal (46%) and excretion was completed after 6 days. Only trace quantities of parent compound were found in the urine.7