Oxaprozin demonstrates high oral bioavailability (95%), with peak plasma concentrations occurring between 3 and 5 hours after dosing. Food may reduce the rate of absorption of Oxaprozin, but the extent of absorption is unchanged. Antacids have no effect on the rate or extent of Oxaprozin absorption.

CLINICAL STUDIES

In a study Daypro was evaluated for managing the signs and symptoms of Rheumatoid Arthritis in placebo and active controlled clinical trials in a total of 646 patients. Daypro was given in single or divided daily doses of 600 to 1 800 mg/day and was found to be comparable to 2 600 to 3 900mg/day of aspirin. At these doses there was a trend (over all trials) for Oxaprozin to be more effective and cause fewer gastrointestinal side effects than Disprin.
Daypro was given as a once-a-day dose of 1 200mg in most of the clinical trials, but larger doses (up to 26mg/kg or 1800mg/day) were used in selected patients. In some patients, Daypro may be better tolerated in divided doses. Due to its long half-life, several days of Daypro therapy were needed for the drug to reach its full effect

Daypro was evaluated for the management of the signs and symptoms of osteoarthritis in a total of 616 patients in active controlled clinical trials against aspirin (N=464), Piroxicam (N=102), and other NSAIDs. Daypro was given both in variable (600 to 1200mg/day) and in fixed (1200mg/day) dosing schedules in either single of divided doses. In these trials, Oxaprozin was found to be comparable to 2600 to 3200 mg/day doses of aspirin or 20mg/day doses of Piroxicam. Oxaprozin was effective both in once-daily and in divided dosing schedules. In controlled clinical trials several days of Oxaprozin therapy were needed for the drug to reach its full effects

Daypro, like other NSAIDs, shows considerable interindividual differences in both pharmacokinetics and clinical response (pharmacodynamics). Therefore, the dosage for each patient should be individualised according to the patient’s response to therapy.
The usual starting dose for most normal weight patients with rheumatoid arthritis is 1 200mg, once a day.
The usual starting dose for normal weight patients with mild to moderate osteoarthritis is 600mg, once a day.

Daypro is indicated for acute and long-term use in the management of the signs and symptoms of osteoarthritis and rheumatoid arthritis.

As with other non-steroidal anti-inflammatory drugs, borderline elevations of one or more liver tests may occur in up to 15% of patients. These abnormalities may progress, remain essentially unchanged, or resolve with continue therapy.

Renal Effects

Acute interstitial nephritis, hematuria and proteinuria have been reported with Daypro as with other NSAIDs. Long-term administration of some non-steroidal anti-inflammatory drugs to animals has resulted in renal papillary necrosis and other abnormal renal pathology. This was not observed with Oxaprozin, but the clinical significance of the difference is unknown.

Rheumatoid Arthritis

The usual daily dose of Daypro for the management of the signs and symptoms of rheumatoid arthritis is 1200mg (two 600mg caplets) once a day

The usual daily dose of Daypro for the management of the signs and symptoms of moderate to severe osteoarthritis is 1200mg (two 600mg caplets) once a day. For patients of low body weight or with milder disease, an initial dosage of one 600mg caplet once a day may be appropriate.
Regardless of the indication, the dosage should be individualised to the lowest effective dose of Daypro to minimise adverse effects, and the maximum recommend total daily dose is 1800mg (or 26mg/kg) whichever is lower) in divided doses.