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trademark for a preparation of diflunisal, a nonsteroidal antiinflammatory drug.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.


(dye-floo-ni-sal) ,


(trade name),


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Therapeutic: nonopioid analgesics
Pharmacologic: salicylic acid derivatives
Pregnancy Category: C (first and second trimester)
Pregnancy Category: D (third trimester)


Inflammatory disorders including:
  • Rheumatoid arthritis,
  • Osteoarthritis.
Treatment of mild to moderate pain.


Inhibits prostaglandin synthesis.
Diflunisal is an NSAID chemically related to aspirin.

Therapeutic effects

Suppression of pain and inflammation.


Absorption: Well absorbed from the GI tract.
Distribution: Crosses the placenta; enters breast milk.
Protein Binding: >99%.
Metabolism and Excretion: Metabolized by the liver; excreted in urine as unchanged drug (3%) and as inactive metabolites.
Half-life: 8–12 hr.

Time/action profile

PO (analgesic)1 hr2–3 hr8–12 hr
PO (anti-inflammatory)few days–1 wk2 wkunknown


Contraindicated in: Hypersensitivity; Cross-sensitivity may exist with other NSAIDs and aspirin; Active GI bleeding or ulcer disease; Patients with recent history of coronary artery bypass surgery; Pregnancy (3rd trimester); Lactation.
Use Cautiously in: Severe renal or hepatic disease; History of cardiovascular disease; History of ulcer disease; Adolescents (may increase the risk of Reye’s syndrome if used during viral illness); Alcohol use; Elderly (increased risk of adverse effects); Pregnancy (1st and 2nd trimesters); Children < 12 yr (safety not established).

Adverse Reactions/Side Effects

Central nervous system

  • dizziness
  • drowsiness
  • headache

Ear, Eye, Nose, Throat

  • tinnitus


  • arrhythmias
  • ↑ in BP
  • chest pain
  • edema


  • GI bleeding (life-threatening)
  • abdominal discomfort (most frequent)
  • nausea (most frequent)
  • constipation
  • diarrhea
  • dyspepsia
  • vomiting


  • renal failure


  • rash


  • blood dyscrasias
  • prolonged bleeding time


  • allergic reactions including anaphylaxis (life-threatening)
  • chills


Drug-Drug interaction

Concurrent use with aspirin may decrease effectiveness.Additive adverse GI effects with aspirin, other NSAIDs, colchicine, corticosteroids, or alcohol.Chronic use with acetaminophen may increase the risk of adverse renal and hepatic reactions (increases acetaminophen blood levels by 50%).May decrease the effectiveness of diuretics or antihypertensives; but increases levels of hydrochlorothiazide.May increase the hypoglycemic effects of sulfonylureas.Probenecid increases risk of toxicity from diflunisal.Increased risk of bleeding with some cephalosporins or anticoagulants.May increase levels and increase the risk of toxicity from cyclosporine, digoxin,lithium, or methotrexate.Increased risk of adverse hematologic reactions with antineoplastics or radiation therapy.Administration with antacids decreases absorption of diflunisal.May increase the risk of adverse renal reactions when used with gold compounds.Increased bleeding risk with anise, arnica, chamomile, clove, feverfew, garlic, ginger, ginkgo, ginseng, and others.


Oral (Adults) Anti-inflammatory—250–500 mg twice daily (maximum daily dose = 1.5 g). Analgesic—500 mg–1 g initially, then 250–500 mg q 8–12 hr (maximum daily dose = 1.5 g).

Availability (generic available)

Tablets: 250 mg, 500 mg

Nursing implications

Nursing assessment

  • Patients who have asthma, aspirin-induced allergy, and nasal polyps are at increased risk for developing hypersensitivity reactions. Routinely monitor BP in patients with history of hypertension.
  • Arthritis: Assess pain and range of motion before and periodically during therapy.
  • Pain: Assess pain (type, location, and intensity) before and 1–2 hr after administration.
  • Lab Test Considerations: BUN, serum creatinine, CBC, and liver function tests should be evaluated periodically in patients receiving prolonged course of therapy.
    • Serum creatinine, AST, ALT, and LDH may show increased levels. Serum uric acid levels may be decreased.
    • May cause minimally prolonged bleeding time at higher doses, which may persist for less than 1 day after discontinuation of therapy.

Potential Nursing Diagnoses

Acute pain (Indications)
Impaired physical mobility (Indications)
Deficient knowledge, related to medication regimen (Patient/Family Teaching)


  • Coadministration with opioid analgesics may have additive analgesic effects and may permit lower opioid doses.
  • Oral: For rapid initial effect, administer 30 min before or 2 hr after meals. May be administered with food, milk, or antacids to decrease GI irritation. Tablets should be swallowed whole; do not crush or chew.

Patient/Family Teaching

  • Advise patient to take diflunisal with a full glass of water and to remain in an upright position for 15–30 min after administration.
  • Instruct patient to take diflunisal exactly as directed. If a dose is missed, it should be taken as soon as remembered but not if almost time for the next dose. Do not double doses.
  • May cause drowsiness or dizziness. Advise patient to avoid driving or other activities requiring alertness until response to the medication is known.
  • Caution patient to avoid concurrent use of alcohol, aspirin, other NSAIDs, acetaminophen, or other OTC medications without consulting health care professional.
  • Instruct patient to notify health care professional of medication regimen before treatment or surgery.
  • Advise patient to consult health care professional if rash, itching, visual disturbances, tinnitus, weight gain, edema, black stools, persistent headache, or influenza-like syndrome (chills, fever, muscle aches, pain) occurs.
  • Centers for Disease Control and Prevention warn against giving aspirin or salicylates to children or adolescents with varicella (chickenpox) or influenza-like or viral illnesses because of a possible association with Reye’s syndrome.
  • Advise patient to notify health care professional if pregnancy is planned or suspected.

Evaluation/Desired Outcomes

  • Decrease in severity of mild to moderate pain.
  • Improved joint mobility. Partial arthritic relief is usually seen within 1–2 wk, with maximum effectiveness seen in several weeks. Patients who do not respond to one NSAID may respond to another.
Drug Guide, © 2015 Farlex and Partners


A trademark for the drug diflunisal.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.
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anti-inflammatories) 1,050-1,160 Naprosyn and Anaprox (Syntex) 540-650 Feldene (Pfizer) 210 Dolobid, Indocin, Clinoril (Merck) 300 Antacids 550-600 Carafate (Marion Merrell Dow) 125-150 Tagamet (SmithKline Beecham) 125-150 Zantac (Glaxo) 100 Pepcid (Merck) 150 Axid (Lilly) 50 Gynecological antifungals 175-185 Monistat 7 (Johnson & Johnson) 100 Gyne-Lotrimin (Schering-Plough) 75-85 Other antifungals and anti-infectives 200 Nizoral (Janssen)
These include Naprosyn (Syntex Corp.); Feldene (Pfizer Inc.); and Dolobid, Indocin and Clinoril (Merk & Co.).