Clinical pharmacokinetics of piroxicam.

Piroxicam is readily absorbed after oral administration. Food and antacids have been shown not to interfere with its bioavailability. Piroxicam is highly bound (approximately 99%) to plasma proteins and has a small distribution volume (approximately 10 l). Despite its high plasma binding, the drug readily penetrates into synovial fluid. Piroxicam has a long elimination half-life of about 50 h. Elimination of the parent drug is mainly the result of biotransformation. The elimination of piroxicam is impaired in some elderly patients, resulting in a high interindividual variability in average steady state levels following a standard 20 mg/day dosage regimen.