Annette (Gbemudu) Ogbru, PharmD, MBA
Annette (Gbemudu) Ogbru, PharmD, MBA
Dr. Gbemudu received her B.S. in Biochemistry from Nova Southeastern University, her PharmD degree from University of Maryland, and MBA degree from University of Baltimore. She completed a one year post-doctoral fellowship with Rutgers University and Bristol Myers Squibb.
Medical and Pharmacy Editor:
GENERIC NAME: diflunisal
BRAND NAME: Dolobid (This brand is no longer available in the U.S.)
DRUG CLASS AND MECHANISM: Diflunisal is a nonsteroidal antiinflammatory drug (NSAID) that is effective in treating fever, pain, and inflammation in the body. Other members of this class include ibuprofen (Motrin), indomethacin (Indocin), nabumetone (Relafen), naproxen (Anaprox, Naprosyn, Aleve) and several others. These drugs are used for the management of mild to moderate pain, fever, and inflammation. They work by reducing the levels of prostaglandins, chemicals that are responsible for pain, fever, and inflammation. Diflunisal blocks the enzymes that make prostaglandins (cyclooxygenases), resulting in lower concentrations of prostaglandins. As a consequence, inflammation, pain and fever are reduced. Diflunisal was approved by the FDA in April 1982.
GENERIC AVAILABLE: Yes
PREPARATIONS: Tablets: 250 and 500 mg.
STORAGE: Diflunisal tablets should be stored in well-sealed containers at a temperature less than 40 C (104 F), preferably at 15–30 C (59-86 F).
DOSING: For mild to moderate pain, an initial dose of 1000 mg followed by 500 mg every 12 hours is recommended for most patients. For osteoarthritis and rheumatoid arthritis, the suggested dosage range is 250 mg to 500 mg twice daily.
DRUG INTERACTIONS: Concomitant use of NSAIDs with angiotensin-converting enzyme (ACE) inhibitors such as enalapril (Vasotec) or angiotensin II receptor antagonists such as irbesartan (Avapro) may reduce the blood pressure response to the antihypertensive agent since prostaglandins are important in controlling blood pressure.
Diflunisal may increase the blood levels of lithium (Eskalith) by reducing the excretion of lithium by the kidneys. Increased levels of lithium may lead to lithium toxicity.
When diflunisal is used in combination with methotrexate (Rheumatrex, Trexall), the blood levels of methotrexate may increase, presumably because the elimination from the body is reduced. This may lead to more methotrexate related side effects.
Individuals taking oral blood thinners or anticoagulants, for example, warfarin, (Coumadin) should avoid diflunisal because diflunisal also thins the blood, and excessive blood thinning may lead to bleeding.
PREGNANCY: There are no adequate studies with diflunisal in pregnant women. Diflunisal should be used only if the potential benefit justifies the potential risk.
NURSING MOTHERS: Diflunisal is excreted in human milk and has a potential for adverse events to infants.
SIDE EFFECTS: Most patients benefit from diflunisal and other NSAIDs with few side effects. However, serious side effects can occur and generally tend to be seen at higher doses. Therefore, it is often desirable to use the lowest effective dose to minimize side effects. The most common side effects of diflunisal involve the gastrointestinal system. It can cause ulcerations, abdominal burning, pain, cramping, nausea, gastritis, and even serious gastrointestinal bleeding and liver toxicity. Sometimes, stomach ulceration and bleeding can occur without any abdominal pain. Black tarry stools, weakness, and dizziness upon standing may be the only signs of internal bleeding. Rash, kidney impairment, ringing in the ears, and lightheadedness also are seen.
Reference: FDA Prescribing Information
Last Editorial Review: 10/8/2009
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