Diflunisal is used for the acute or long-term relief of mild to moderate pain. Diflunisal is also used for anti-inflammatory and analgesic effects in the symptomatic treatment of acute and chronic rheumatoid arthritis and osteoarthritis. Diflunisal is not recommended for use as an antipyretic agent.
The potential benefits and risks of diflunisal therapy as well as alternative therapies should be considered prior to initiating diflunisal therapy. The lowest possible effective dosage and shortest duration of therapy consistent with treatment goals of the patient should be employed.
Diflunisal is used for symptomatic relief of postoperative (including that associated with dental surgery), postpartum, and orthopedic (including musculoskeletal sprains or strains) pain and visceral pain associated with cancer. When used to relieve mild to moderate acute pain, a single 500-mg dose of diflunisal has been reported to be as effective as a single 650-mg dose of aspirin, a 600- or 650-mg dose of acetaminophen, or a 650-mg dose of acetaminophen with 100 mg of propoxyphene napsylate. A single 1-g dose of diflunisal has been reported to be as effective as a single 600-mg dose of acetaminophen with 60 mg of codeine. Diflunisal dosages of 500 mg twice daily have been reported to be as effective as 50 mg of oral pentazocine 4 times daily or as 200 mg of oxyphenbutazone 3 times daily. When used to relieve oral surgery pain, 250-mg, 500-mg, or 1-g doses of diflunisal appear to be more effective than 650-mg doses of aspirin. In the treatment of episiotomy pain in one study, the analgesic effect of 500-mg doses of diflunisal has been reported to be greater than that of 600-mg doses of aspirin. Diflunisal has a longer duration of analgesic activity than many other similar analgesics (e.g., aspirin); however, the onset of diflunisal's analgesic activity may be delayed. In several studies, 500-mg and 1-g doses of diflunisal have produced symptomatic relief for up to 12 hours in most patients with postoperative pain. Initiating therapy with a 1-g loading dose of diflunisal results in an initial analgesic effect that has a more rapid onset, a shorter time to peak, and a greater intensity at peak than that associated with an initial 500-mg dose.
Rheumatoid Arthritis and Osteoarthritis
When used in the symptomatic treatment of rheumatoid arthritis, diflunisal has relieved pain and stiffness, reduced joint tenderness, and improved mobility and grip strength. In the symptomatic treatment of osteoarthritis, diflunisal has relieved pain and stiffness and has increased range of motion and functional activity. Diflunisal appears to be only palliative in these conditions and has not been shown to permanently arrest or reverse the underlying disease process. Most clinical studies have shown that the anti-inflammatory and analgesic effects of usual dosages of diflunisal in the management of rheumatoid arthritis or osteoarthritis are about equal to those of usual dosages of salicylates, ibuprofen, or naproxen. In controlled clinical studies of 8-12 weeks' duration in patients with rheumatoid arthritis or osteoarthritis, 500 mg to 1 g of diflunisal daily was as effective as 2-4 g of aspirin daily.
Patient response to oral NSAIAs is variable; patients who do not respond to or cannot tolerate one NSAIA might be successfully treated with a different agent. However, NSAIAs are generally contraindicated in patients in whom sensitivity reactions (e.g., urticaria, bronchospasm, severe rhinitis) are precipitated by aspirin or other NSAIAs.
(See Cautions: Precautions and Contraindications.)
In the management of rheumatoid arthritis in adults, NSAIAs may be useful for initial symptomatic treatment; however, NSAIAs do not alter the course of the disease or prevent joint destruction. Disease modifying antirheumatic drugs (DMARDs) (e.g., azathioprine, cyclosporine, etanercept, oral or injectable gold compounds, hydroxychloroquine, infliximab, leflunomide, methotrexate, minocycline, penicillamine, sulfasalazine) have the potential to reduce or prevent joint damage, preserve joint integrity and function, and reduce total health care costs, and all patients with rheumatoid arthritis are candidates for DMARD therapy. DMARDs should be initiated early in the disease course and should not be delayed beyond 3 months in patients with active disease (i.e., ongoing joint pain, substantial morning stiffness, fatigue, active synovitis, persistent elevation of erythrocyte sedimentation rate [ESR] or C-reactive protein [CRP], radiographic evidence of joint damage) despite an adequate regimen of NSAIAs. NSAIA therapy may be continued in conjunction with DMARD therapy or, depending on patient response, may be discontinued. For further information on the treatment of rheumatoid arthritis, see Uses: Rheumatoid Arthritis, in Methotrexate 10:00.)
The addition of diflunisal to a regimen of gold compounds has resulted in increased symptomatic relief in some patients with rheumatoid arthritis but has not reversed the underlying disease process. Diflunisal and gold compounds may be used concomitantly at their usual dosage levels.
Results from a large, prospective, population-based cohort study in geriatric individuals indicate a lower prevalence of Alzheimer's disease among patients who received an NSAIA for 2 years or longer. Similar findings have been reported from some other, but not all, observational studies.