The efficacy and relative bioavailability of diclofenac resinate in rheumatoid arthritis patients

The pharmacodynamics and pharmacokinetics of 75 mg resin-bound diclofenac (resinate) were compared with enteric-coated tablets containing 75 mg of diclofenac in a double-blind randomized crossover trial in 16 patients suffering from rheumatoid arthritis. Diclofenac was significantly faster absorbed from the resinate than from the enteric coated formulation (tlag = 0.454 h vs. 0.998 h, tmax = 1.41 h vs. 2.56 h) and reached lower peak concentrations (Cmax = 1.64 micrograms/ml vs. 2.59 micrograms/ml). No significant differences were found concerning the area under the plasma level-time curves and the mean residence times. Smaller variances were found for the tmax and the mean residence times in the group treated with diclofenac resinate. Onset and duration of analgesia, as assessed by visual analogue scales were similar in both treatment groups, but did not correlate with the plasma concentrations. Four patients experienced adverse effects including gastric pain, transaminase increases, proteinuria and plasma creatinin increase. No uncommon adverse effects were observed with the new preparation.