Pharmacology Of Oxaprozin

Indication Used to relieve the inflammation, swelling, stiffness, and joint pain associated with rheumatoid arthritis and osteoarthritis.
Pharmacodynamics Oxaprozin is a nonsteroidal anti-inflammatory drug (NSAID) with analgesic and antipyretic properties. Oxaprozin is used to treat rheumatoid arthritis, osteoarthritis, dysmenorrhea, and to alleviate moderate pain.
Mechanism of action Anti-inflammatory effects of Oxaprozin are believed to be due to inhibition of cylooxygenase in platelets which leads to the blockage of prostaglandin synthesis. Antipyretic effects may be due to action on the hypothalamus, resulting in an increased peripheral blood flow, vasodilation, and subsequent heat dissipation. Oxaprozin is a non-selective NSAID, with a cell assay system showing lower COX-2 selectivity implying higher COX-1 selectivity.
Absorption Oxaprozin is 95% absorbed after oral administration. Food may reduce the rate of absorption of oxaprozin, but the extent of absorption is unchanged. Antacids do not significantly affect the extent and rate of oxaprozin absorption.
Volume of distribution
  • 11 to 17 L/70 kg
Protein binding >99.5% bound to albumin
Metabolism Hepatic. Ester and ether glucuronide are the major conjugated metabolites of oxaprozin, and do not have significant pharmacologic activity.
Route of elimination Oxaprozin is expected to be excreted in human milk based on its physical-chemical properties; however, the amount of oxaprozin excreted in breast milk has not been evaluated. Approximately 95% of oxaprozin is metabolized by the liver. Approximately 5% of the oxaprozin dose is excreted unchanged in the urine. Sixty-five percent (65%) of the dose is excreted in the urine and 35% in the feces as metabolite. Biliary excretion of unchanged oxaprozin is a minor pathway. Several oxaprozin metabolites have been identified in human urine or feces.
Half life 54.9 hours
Clearance Not Available
Toxicity Oral, mouse: LD50 = 1210 mg/kg; Oral, rabbit: LD50 = 172 mg/kg; Oral, rat: LD50 = 4470 mg/kg