Tiflamizole elimination from plasma in rheumatoid arthritis

Tiflamizole is a fluorinated diarylamidazole sulfone nonsteroidal anti-inflammatory drug not metabolized or excreted in urine. Its mean (+/- SD) elimination t 1/2 from plasma was 21.6 +/- 9 days (range 11.8 to 49.5 days) in 17 subjects with rheumatoid arthritis, and appeared to be first order in most of them. Plasma elimination t 1/2 was loosely related (r = -0.67) to stool frequency in eight subjects for whom stool frequency data were available. In one, cholestyramine decreased t 1/2 to 4.1 days. In two patients, synovial fluid total tiflamizole concentrations were approximately one-third of simultaneous plasma concentrations, but elimination t 1/2s from synovial fluid were of the same order as those from plasma. Even with infrequent dosing, the longer t 1/2 may help sustain the anti-inflammatory effects of this drug.