Diclofenac/misoprostol compared with diclofenac in the treatment of osteoarthritis of the knee or hip: a randomized, placebo controlled trial. Arthrotec Osteoarthritis Study Group.

Objective: Gastric (GU) and duodenal ulcers (DU) are common adverse effects of nonsteroidal anti-inflammatory drugs (NSAID). Endoscopically diagnosed upper gastrointestinal (GI) ulceration occurs in about 24% of longterm NSAID users. Coadministration of misoprostol with the NSAID reduces the incidence of NSAID induced GU and DU and their complications. However, compliance is limited by the different dosing regimens of misoprostol and NSAID and GI symptoms associated with misoprostol at its recommended q.i.d. dose. We compared the efficacy, safety, and incidence of endoscopic upper GI ulceration associated with the administration of 2 combinations of diclofenac (50 or 75 mg) and misoprostol 200 microg (D50/M200 t.i.d., D75/M200 b.i.d.), diclofenac 75 mg b.i.d., and placebo in a 6 week, randomized, double blind study in patients with osteoarthritis (OA) of the knee or hip.
Methods: A total of 572 patients with symptomatic OA of the knee or hip and history of GU, DU. or 10 or more erosions were randomized to receive D50/M200 t.i.d., D75/M200 b.i.d., diclofenac 75 mg b.i.d., or placebo for 6 weeks. Arthritis assessments were performed at baseline, 2, and 6 weeks, and upper GI endoscopies at baseline and end of treatment.
Results: All active treatment groups were significantly better than placebo, at all visits, in improving OA symptoms. There were no significant differences in arthritis efficacy between the diclofenac/ misoprostol combinations and diclofenac. However, endoscopically diagnosed GU and/or DU were significantly less frequent in patients receiving D50/M200 t.i.d. (8%), D75/M200 b.i.d. (7%), and placebo (4%) compared to diclofenac 75 mg b.i.d. (17%). Adverse events were not different between the active treatment groups, except for higher incidences of flatulence with D75/M200 and diarrhea with D50/M200.
Conclusion: Diclofenac 50 mg/misoprostol 200 microg t.i.d. and diclofenac 75 mg/misoprostol 200 microg b.i.d. are as efficacious as diclofenac 75 mg b.i.d. in the treatment of OA, but are associated with a significantly lower incidence of gastric and/or duodenal ulcers.