To conduct the first Canadian study of the comparative efficacy and safety of tenoxicam and diclofenac in patients with primary osteoarthritis (OA) of the knee.
Tenoxicam 20 mg per os once daily (po od) was compared to diclofenac (Voltaren) 50 mg per os 3 times a day (po tid) in a 12-week, double blind, randomized, controlled, multicenter, parallel trial. The primary outcome measure was the pain dimension of the WOMAC OA Index. Following an initial screening visit and a 3 to 7 day NSAID-free washout period (i.e., baseline), patients were assessed at Weeks 2, 4 and 12; assessments including some 15 efficacy variables and safety variables.
Ninety-eight patients [tenoxicam (n = 48), diclofenac (n = 50)] participated in the trial. Statistically significant (p < or = 0.05) improvements in all 3 dimensions of the WOMAC OA Index and six efficacy variables were noted in both treatment groups. No significant between drug differences were noted on any efficacy variable. Significantly fewer patients reported adverse events in the tenoxicam group (21 vs 33, p = 0.03).
Tenoxicam is efficacious and well tolerated in patients with OA of the knee. In this group of patients it was similar in efficacy and superior in tolerability to diclofenac 150 mg/day (50 mg tid). Thus the benefit/risk ratio of tenoxicam was superior to that of diclofenac in this study.