Diflunisal: a review of its pharmacological properties and therapeutic use in pain and musculoskeletal strains and sprains and pain in osteoarthritis.

Diflunisal is a salicylic acid derivative with analgesic and anti-inflammatory activity. It has been studied in osteoarthritis, pain resulting from musculoskeketal sprains and strains and from minor surgery and cancer. The duration of its analgesic effect is longer than that of aspirin and diflunisal is effective when given twice daily. Diflunisal is not metabolised to salicylic acid and has a lesser effect than aspirin on platelet function in vivo. In osteoarthritis, diflunisal appears comparable in efficacy to moderate doses of aspirin (2 to 3g daily), but is better tolerated. It has not been compared with the most active phenylalkanoic acid derivatives such as naproxen in adequate numbers of patients. Diflunisal is comparable with glafenine in pain and with propoxyphene/paracetamol combinations and oxyphenbutazone in pain and in musculoskeletal strains and sprains. As with other non-steroidal agents, gastrointestinal complaints are the most frequently reported side effects.