Oxaprozin dosing

Oxaprozin (Daypro) is approved for the treatment of osteoarthritis and rheumatoid arthritis. Its long half-life allows for once daily dosing. The most frequently reported adverse effects of this drug are nausea, vomiting, and dyspepsia. 

Oxaprozin shows selectivity for COX-1 in human cellular assays and a more balanced inhibition of both COX-1 and COX-2 in a whole blood assay. It is given orally (600-1200 mg/day, maximum dose 1800 mg/day). 

Kolodny AL, Klipper AR, Harris BK, et al. The efficacy and safety of single daily doses of oxaprozin in the treatment of osteoarthritis a comparison with aspirin. Semin Arthritis Rheum 1986 15 72. 

Oxaprozin (Daypro) has similar pharmacological properties, adverse effects, and therapeutic uses to those of other propionic acid derivatives. However, its pharmacokinetic properties differ considerably. Peak plasma levels are not achieved until 3 to 6 hours after an oral dose, whereas its half-life of 40 to 60 hours allows for once-daily adminisffation. 

Oxaprozin is a non-steroidal antiinflammatory agent indicated for use in various forms of rheumatoid arthritis, osteoeirthritis, and ankylosing spondylitis. A long Th allows once/twice daily dosing. Structur ly it is somewhat unique, being a 3-substituted, rather than a 2-substituted propionic acid. 

Oxaprozin possesses a relatively long elimination half-life of 59 hours (range, 26-92 hours), enabling once-daily dosing. Administration with food appears to delay absorption but not bioavailability. 

There was no difference in the pharmacokinetics of a single 1.2-g dose of oxaprozin in 11 women taking conjugated oestrogens (Premarin) than in 11 control women, except that the time to peak concentration was shorter (4 versus 8.9 hours). This difference is unlikely to be of clinical importance. 

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