Two generic bioequivalent copies of the same drug sometimes do not achieve therapeutic equivalence. This may produce adverse events in clinical practice if the therapeutic index of that drug is narrow.
To compare the efficacy and safety of two generic copies of nimesulide Nimulid (N) and Tenaprost (T).
60 out-patients with symptomatic low back pain or knee osteoarthritis were randomized to take T or N (100 mg 2 x/day for 20 days) in a prospective double-blinded randomized phase four clinical trial conducted at the Institute of Rheumatology, Belgrade, Serbia. Pain was evaluated by VAS. Paravertebral muscle spasm (PVM), sagittal mobility, and the Lasegue's test (LT) were estimated in low back pain. In knee osteoarthritis, knee circumference, motion, and knee tendons sensitivity (KTS) to palpation were assessed. Adverse events reported by the patients, or observed by the investigators were recorded.
T and N significantly reduced pain levels in patients with low back pain and knee osteoarthritis (p<0.001) as well as knee circumference and KTS to palpation (p<0.05). Compared to N, T showed slightly better effects on the Lequesne functional index (p<0.05) and PVM spasm in patients with lower back pain, but that was not of clinical relevance. Tolerability of T and N was good.
T and N are equally effective and safe forms of nimesulide for pain management in low back pain and knee osteoarthritis. Price per daily dose is a relevant parameter for making a choice. However, regulations regarding drug bioequivalence criteria should be met for drug marketing authorization submission.