Classifications: analgesic, nonsteroidal antiinflammatory drug (nsaid); antipyretic; Therapeutic:nsaid, analgesic; antipyretic
Pregnancy Category: C
250 mg, 500 mg tablets
A long-acting nonsteroidal antiinflammatory drug (NSAID); unlike aspirin, inhibition of platelet function and effect on bleeding time are dose related and reversible, lasting
only about 24 h after drug is discontinued. Is a non-narcotic analgesic agent. Exerts mild antipyretic effect; therefore
it is not used clinically for this purpose. This NSAID has peripheral analgesic properties due to interfering with prostaglandin
synthesis by inhibiting cyclooxygenase (COX) isoenzymes, COX-1 and COX-2.
Has analgesic and anti-inflammatory properties.
Acute and long-term relief of mild to moderate pain and symptomatic treatment of osteoarthritis and rheumatoid arthritis.
Patients in whom aspirin or other NSAIDs precipitate an acute asthmatic attack (bronchospasm), urticaria, angioedema, severe rhinitis, or shock; active peptic
ulcer, GI bleeding; severe salicylate hypersensitivity. Safe use in children <12 y is not established. Pregnancy (category
C); use during third trimester of pregnancy specifically contraindicated because NSAIDs are known to cause premature closure of ductus arteriosus in fetus.
History of upper GI disease; preexisting renal disease; impaired renal or hepatic function; alcoholics; compromised cardiac
function, and other conditions associated with fluid retention; patients receiving diuretics; bone marrow suppression; geriatric
patients; hypertension; patients who may be adversely affected by prolonged bleeding time; lactation.
Route & Dosage
Adult: PO 1000 mg followed by 500 mg q812h
Adult: PO 5001000 mg/d in 2 divided doses (max: 1500 mg/d)
- Give with water, milk, or food to reduce GI irritation. Food causes slight reduction in absorption rate, but does not affect
total amount absorbed.
- Store at 15°30° C (59°86° F) in tightly closed containers unless otherwise directed.
Adverse Effects (≥1%)Body as a Whole:
Hypersensitivity syndrome (fever, chills, rash, eosinophilia, changes in renal and hepatic function, anaphylactic reactions with bronchospasm
Headache, drowsiness, insomnia
, dizziness, vertigo, light-headedness, fatigue
, weakness, nervousness, confusion, disorientation. CV:
Palpitation, tachycardia, peripheral edema. Special Senses:
Tinnitus, hearing loss; blurred vision, reduced visual acuity, changes in color vision, scotomas, corneal deposits, retinal
disturbances. GI: Nausea,
GI pain, flatulence, GI bleeding, peptic ulcer
, anorexia, eructation, cholestatic jaundice
Hematuria, proteinuria, interstitial nephritis, renal failure. Hematologic:
Prolonged PT, anemia, decreased serum uric acid, transient elevations of liver function tests. Skin:
Rash, toxic epidermal necrolysis, exfoliative dermatitis, urticaria. Other:
Weight gain, hyperventilation, dyspnea, photosensitivity.
Diagnostic Test Interference
Diflunisal can lower serum uric acid concentrations by as much as 1.4 mg/dL and increased renal clearance of uric acid.
decrease diflunisal absorption; aspirin
and other nsaids
increase risk of GI bleeding; increases risk of warfarin
-induced hypoprothrombinemia; increases methotrexate
levels and toxicity.
Readily from GI tract. Onset:
1 h. Peak:
23 h. Duration:
12 h. Distribution:
Probably crosses placenta; distributed into breast milk. Metabolism:
In liver. Elimination:
In urine. Half-Life:
Assessment & Drug Effects
- Monitor for therapeutic effectiveness: Full antiinflammatory effect for arthritis may not occur until 8 d to several weeks
- Discontinue if patient presents signs of hepatic toxicity (see Appendix F).
- Note: Although the antipyretic effect is mild, chronic or high doses may mask fever in some patients.
Patient & Family Education
- Swallow tablet whole; do not crush or chew.
- Take drug as prescribed. Doubling the dosage can produce greater than doubling of drug accumulation, particularly in patients
receiving repetitive doses.
- Report onset of visual or auditory problems immediately to physician.
- Be aware of I&O ratio and pattern and check for and report peripheral edema and unusual weight gain.
- Report promptly to physician the onset of melena, hematemesis, or severe stomach pain.
- Do not drive or engage in other potentially hazardous activities until reaction to drug is known.