抄録
The present study was undertaken to investigate the serum levels and penetrability of piroxicam into synovial fluid in patients with rheumatoid arthritis who were treated with ampiroxicam 27 mg once daily over a long period of time.
The serum levels were determined on 120 blood samples withdrawn from 44 patients and synovial fluid concentrations on 4 samples obtained from 3 patients. The results are summarized as follows.
(1) The piroxicam serum concentrations were 5.45±0.34μg/ml (mean±standard error) for 59 samples of patients treated for 14 weeks or less, 5.74±0.37 μg/ml for 38 samples of those treated for 15-26 weeks, 5.73±0.63 μg/ml for 19 samples of those treated for 27-46 weeks and 5.07±0.88 μg/ml for 4 samples of those whose treatment period was 47 weeks or more, all showing about the same levels.
(2) The piroxicam levels in synovial fluid were about 53% of plasma levels indicating a good penetrability of the drug.
(3) The correlation of the piroxicam serum concentrations with the clinical efficacy of ampiroxicam was unclear nor with the safety (in terms of development of side effect or laboratory abnormal values) .
The foregoing results suggest that when ampiroxicam is given as a single dose of 27 mg once daily to the patients with rheumatoid arthritis over a long period of time, the piroxicam levels in serum are maintained within an about fixed range not showing any increase or accumulation enhanced by a long term dosing and once a steady state is reached, the level is sustained over a long period of time.
