Ibuprofen and Diclofenac Sodium in the Treatment of Osteoarthritis: A Comparative Trial of Two Once-Daily Sustained-Release NSAID Formulations

Summary An investigator-blind, parallel-group, multicentre study was undertaken to compare the efficacy and tolerability of once-daily, sustained-release (s-r) ibuprofen and diclofenac sodium in patients (mean age 59.8 years) suffering from painful osteoarthritis affecting chiefly the knee and/or hip. Patients attending eight Swiss centres received either two s-r tablets of ibuprofen (daily dose 1600 mg; n = 30) or a single s-r diclofenac 100 mg tablet (n = 31) each evening for 21 days. Clinical assessments were performed prior to initiating therapy and after 7 and 21 days of treatment. Both treatments were efficacious, but statistically significant differences in favour of s-r ibuprofen were observed for the principal measure of efficacy, the investigator's assessment of the overall change in clinical condition; by Day 21, 37% of ibuprofen-treated patients vs 10% of diclofenac-treated patients were ‘much improved’ (p = 0.04). Patients’ assessments of the efficacy of their treatment also favoured s-r ibuprofen at Day 7 for the relief of night pain (p = 0.048), at Day 21 for alleviation of day pain (p = 0.006) and for the ability to carry out normal activities (p = 0.01), and at both Days 7 and 21 for quality of sleep (p = 0.04 and 0.03, respectively). The patients’ overall opinion of treatment was also significantly in favour of s-r ibuprofen, which was rated ‘good or excellent’ by 80% (24/30), compared with only 38% of patients (11/29) receiving s-r diclofenac sodium (p = 0.002). Two patients (6%) receiving s-r diclofenac sodium ceased treatment owing to dizziness and severe diarrhoea, respectively; there were no withdrawals in the ibuprofen-treated group. Ten (32%) patients in the s-r diclofenac group reported a total of 12 adverse events (mostly gastrointestinal in nature), compared with three (10%) patients in the s-r ibuprofen group who reported only three events (abdominal pain, insomnia and constipation). In conclusion, although both NSAID treatments improved the clinical condition of patients with painful osteoarthritis, statistically significant differences in favour of once-daily s-r ibuprofen (1600 mg) were demonstrated in terms of efficacy, indicating a potential therapeutic advantage for this formulation. Ibuprofen was also better tolerated than diclofenac sodium (100 mg/day), the latter being associated with gastrointestinal side effects in a significant proportion of patients. Sustained-release ibuprofen (Brufen Retard®) thus represents an i