Diflunisal
Diflunisal (Dolobid)
Diflunisal
(dye- FLEW-nih-sal)
Pregnancy Category: C Apo-Diflunisal Dolobid Novo-Diflunisal Nu-Diflunisal (Rx)

Classification: Nonsteroidal analgesic, anti-inflammatory, antipyretic

Action/Kinetics: A salicylic acid derivative, although not metabolized to salicylic acid. Mechanism not known; may be an inhibitor of prostaglandin synthetase. Onset: 20 min (analgesic, antipyretic). Peak plasma levels: 2-3 hr. Peak effect: 2-3 hr. Duration: 4-6 hr t 1/2: 8-12 hr. Ninety-nine percent protein bound. Metabolites excreted in urine.

Uses: Analgesic, rheumatoid arthritis, osteoarthritis, ankylosing spondylitis, psoriatic arthritis, musculoskeletal pain. Prophylaxis and treatment of vascular headaches.

Contraindications: Hypersensitivity to diflunisal, aspirin, or other anti-inflammatory drugs. Acute asthmatic attacks, urticaria, or rhinitis precipitated by aspirin. During lactation and in children less than 12 years of age.

Special Concerns: Use with caution in presence of ulcers or in clients with a history thereof, in clients with hypertension, compromised cardiac function, or in conditions leading to fluid retention. Use with caution in only first two trimesters of pregnancy. Geriatric clients may be at greater risk of GI toxicity.

Side Effects: GI: Nausea, dyspepsia, GI pain and bleeding, diarrhea, vomiting, constipation, flatulence, peptic ulcer, eructation, anorexia. CNS: Headache, fatigue, fever, malaise, dizziness, somnolence, insomnia, nervousness, vertigo, depression, paresthesias. Dermatologic: Rashes, pruritus, sweating, Stevens-Johnson syndrome dry mucous membranes, erythema multiforme. CV: Palpitations, syncope, edema. Other: Tinnitus, asthenia, chest pain, hypersensitivity reactions, anaphylaxis dyspnea, dysuria, muscle cramps, thrombocytopenia.

Overdose Management: Symptoms: Drowsiness, N&V;, diarrhea, tachycardia, hyperventilation, stupor, disorientation, diminished urine output, coma, cardiorespiratory arrest. Treatment: Supportive measures. To empty the stomach, induce vomiting, or perform gastric lavage. Hemodialysis may not be effective since the drug is significantly bound to plasma protein.

Drug Interactions: Acetaminophen / Acetaminophen plasma levels Antacids / Diflunisal plasma levels Anticoagulants / PT Furosemide / Furosemide hyperuricemic effect Hydrochlorothiazide / Hydrochlorothiazide plasma drug levels and hyperuricemic effect Indomethacin / Indomethacin renal clearance plasma levels Naproxen / Urinary naproxen and metabolite excretion

How Supplied: Tablet: 250 mg, 500 mg

Dosage
?Tablets Mild to moderate pain.
Adults, initial: 1,000 mg; then, 250-500 mg q 8-12 hr.
Rheumatoid arthritis, osteoarthritis.
Adults: 250-500 mg b.i.d. Doses in excess of 1,500 mg/day are not recommended. For some, an initial dose of 500 mg followed by 250 mg q 8-12 hr may be effective. Reduce dosage with impaired renal function.