Comparison of gastrointestinal safety and tolerability of aceclofenac with diclofenac: a multicenter, randomized, double-blind study in patients with knee osteoarthritis.

OBJECTIVE: To compare the gastrointestinal (GI) tolerability and efficacy of aceclofenac with diclofenac in patients with knee osteoarthritis (OA).

METHODS: In this randomized, double-blind, double-dummy, multicentric, comparative study, post 7 day placebo washout, patients were randomly allocated to receive either aceclofenac 100 mg b.i.d. or diclofenac 50 mg t.i.d. and were followed up for the next 6 weeks. The GI tolerability was evaluated based on the incidence and severity of predefined GI adverse events (AEs), number of gastroprotective agents (GPAs) consumed by patients, and discontinuation from the study due to GI AEs. The secondary outcome included assessment of pain intensity using a visual analogue scale (VAS), Western Ontario and McMaster Universities (WOMAC) score, pain relief score, and investigators' and patients' overall assessments of response to study drugs.

RESULTS: A total of 591 (aceclofenac group: 297; diclofenac group: 294) patients were enrolled. The cumulative incidence of GI AEs for dyspepsia (28.1% versus 37.9%; p = 0.014), abdominal pain (19% versus 26.3%; p = 0.037), overall incidence of predefined GI AEs (57.3% versus 73.6%; p < 0.001) and number of patients reporting GI AEs (28.9% versus 36.5%; p = 0.053) were significantly less in the aceclofenac group compared to the diclofenac group throughout the study. All the AEs were mild to moderate in intensity. Fewer patients from the aceclofenac group required GPAs compared to the diclofenac group (28.17% versus 33.68%; p = 0.155). During first 7 days of therapy, >90% of patients from aceclofenac group did not require GPAs. There were no differences between the study groups in the various pain assessment scales when measured during the study period.

CONCLUSION: Aceclofenac was better tolerated in terms of incidence and severity of GI AEs and GPA requirement and was as efficacious as diclofenac. The need for GPAs increased with the increase in duration of treatment with NSAIDs. Hence, it could be concluded that usual practice of co-prescription of GPAs with aceclofenac could be avoided to improve patient compliance and reduce cost of treatment. However, long term trials with endoscopic evaluation in the wider population are required to assess the GI tolerability of aceclofenac and diclofenac in detail.