Tenoxicam is well absorbed following oral administration; peak plasma concentrations occur within about 2 hours in fasting subjects; this may be delayed to about 6 hours when tenoxicam is given with food but the extent of absorption is not affected. Tenoxicam is over 98.5% protein bound and penetrates synovial fluid. The plasma elimination half-life is about 60 to 75 hours; with daily administration, steady-state concentrations are reached within 10 to 15 days. Tenoxicam is completely metabolised to inactive metabolites which are excreted mainly in the urine; there is some biliary excretion of glucuronide conjugates of the metabolites.
RHEUMATOID ARTHRITIS, OSTEOARTHRITIS, SHRT TERM TREAMTMENT OF SOFT TISSUE INJURIES, GOUT AND NON-ARTICULAR CONDITIONS SUCH AS TENDINITIS, BURSITIS, BACK PAIN ETC: 20mg once daily. Gout: 40mg/day for 2 days then 20mg daily for 5 days.
Potent inhibitor of prostaglandin synthesis by blocking the enzyme cyclo-oxygenase. Additional actions contributing to the anti-inflammatory action are inhibition of leucocyte function including phagocytosis and chemotaxis, and scavenging free oxygen radicals. At the usual doses, no effect on renal function.
Notable interactions involving NSAIDs include enhancement of the effects of oral anticoagulants (especially by azapropazone and phenylbutazone) and increased plasma concentrations of lithium, methotrexate, and cardiac glycosides. The risk of nephrotoxicity may be increased if given with ACE inhibitors, cyclosporin, tacrolimus, or diuretics. Effects on renal function may lead to reduced excretion of some drugs. There may also be an increased risk of hyperkalaemia with ACE inhibitors and potassium-sparing diuretics. The antihypertensive effects of some antihypertensives including ACE inhibitors, beta blockers, and diuretics may be reduced. Convulsions may occur due to an interaction with quinolones. NSAIDs may enhance the effects of phenytoin and sulphonylurea antidiabetics. The effects of NSAIDs might be enhanced by use with moclobemide. The concomitant use of more than one NSAID (including aspirin) should be avoided because of the increased risk of adverse effects. The risk of gastrointestinal bleeding and ulceration associated with NSAIDs is increased when used with corticosteroids or, possibly, alcohol, bisphosphonates, or oxpentifylline. There may be an increased risk of haemotoxicity during concomitant use of zidovudine and NSAIDs; blood counts 1 to 2 weeks after starting use together are recommended. The manufacturer of mifepristone advises that NSAIDs or aspirin should be avoided for 8 to 12 days after mifepristone use because of a theoretical risk that these prostaglandin synthetase inhibitors may alter the efficacy of mifepristone.
Effect & Precautions
Adverse effects associated with tenoxicam have been reviewed. (1) The majority of adverse effects relate to the gastrointestinal tract (11.4%), nervous system (2.8%), or skin (2.5%).