The pharmacokinetics of etodolac in serum and synovial fluid of patients with arthritis.

The pharmacokinetics of etodolac have been evaluated in five patients with arthritis given 200 mg etodolac, twice daily, at 12-hour intervals, for 7 days. Albumin and total protein concentrations were markedly lower in synovial fluid than in serum, and etodolac free fraction was significantly higher. Etodolac readily penetrated into the synovial fluid, and in the postdistributive phase the concentration of free etodolac (i.e., the drug responsible for pharmacologic activity) remained higher than that in serum at all times. No differences in the half-life of etodolac elimination were noted.