Piroxicam is an N-heterocyclic carboxamide of 1,2 benzothiazine 1,1 dioxide with analgesic and anti-inflammatory activity. It has an extended half-life of about 40 hours and is suitable for once daily administration. Published studies indicate that piroxicam 20mg daily is comparable with aspirin 3 to 6g. indomethacin 75 to 150mg, phenylbutazone 400mg, naproxen 500mg, ibuprofen 1200 to 2400mg and diclofenac 75mg in rheumatoid arthritis. In osteoarthritis, piroxicam 20mg daily is comparable in efficacy with aspirin 2.6 to 3.9g, indomethacin 75mg, naproxen 500mg and fenbufen 600mg but is generally better tolerated than aspirin or indomethacin in patients with arthritic diseases. Piroxicam 20mg was at least as effective as indomethacin 75mg in a study in ankylosing spondylitis. As with other non-steroidal anti-inflammatory drugs gastrointestinal complaints are the most frequently reported side effects and their frequency and severity appears to be dose-related.