A randomized, prospective, double-blinded, phase 4 clinical study was conducted to investigate the safety and efficacy of two generic formulations of nimesulide (a selective cyclooxygenase [COX] -2 inhibitor) in patients having symptomatic low back pain or knee osteoarthritis.

The study recruited 60 out-patients having knee osteoarthritis or low back pain. Participants were randomly allocated to either generic 1 (n=30) group or generic 2 (n=30) (100 mg 2 x/day for 20 days) group. The Visual Analogue Scale (VAS) was effectively used to assess pain intensity.

In the low back pain, the following parameters were assessed: Paravertebral muscle spasm (PVM), Lasegue's test, and sagittal mobility. In the knee osteoarthritis, the following parameters were estimated: motion, knee tendons sensitivity (KTS) to palpation, knee circumference. Adverse events witnessed by the participants, or noted by the researchers were recorded.

In patients suffering from low back pain and knee osteoarthritis, the generic formulations remarkably diminished pain levels. The knee circumference and KTS to palpation were also lowered. Both generic copies showed good tolerability. The safety of both generics was comparable. The most frequent adverse effects were mild and depicted a similar rate in both groups. 

The generic formulations of nimesulide yield satisfactory results in managing low back pain or knee osteoarthritis pain.