Zaltoprofen, a noninferior alternative to diclofenac for the treatment of primary knee osteoarthritis -- a comparative evaluation of efficacy and safety in a 4-week, multicentric, randomized, double-blind, double-dummy trial.

Objective: To demonstrate the clinical noninferiority of the analgesic effect of zaltoprofen (80 mg t.i.d.) compared with diclofenac (50 mg t.i.d.) in active knee osteoarthritis patients.

Method: In this multicentric, double-blind, double-dummy, randomized, parallel-group, comparative study, 213 patients of either sex, aged 40 - 65 years having radiological and clinically confirmed primary knee osteoarthritis were randomized either to zaltoprofen (n = 105) or diclofenac (n = 108) and were followed-up at weeks 1, 2, 3 and 4. The treatment period was preceded by a washout period of 1 week.

Results: Patients in both the zaltoprofen and diclofenac groups exhibited significant improvement (p < 0.001) in pain intensity, functional status and pain relief at each visit from baseline with no statistically significant difference between the two treatment groups. There was no statistically significant difference between the treatment groups for global assessment rating done by the patient and investigator at the end of therapy (p > 0.05) and the proportion of patients who consumed ranitidine (p = 0.135) and paracetamol (p = 0.086) tablets during the treatment period on both the treatment arms. Both the study medications were well tolerated with no incidence of serious adverse events.

Conclusions: This study demonstrated that efficacy and safety of zaltoprofen is clinically noninferior to that of diclofenac.