fenoprofen (Nalfon)

What is fenoprofen, and how does it work (mechanism of action)?

Fenoprofen is a nonsteroidal anti-inflammatory drug (NSAID) that is effective for treating the fever, pain, and swelling caused by inflammation. Fenoprofen belongs to a class of drugs called nonsteroidal anti-inflammatory drugs (NSAIDs). Other members of the NSAID class of drugs include ibuprofen (Motrin), indomethacin (Indocin), nabumetone (Relafen), naproxen (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 the pain, fever, and swelling of inflammation. Fenoprofen blocks the enzymes that make prostaglandins (cyclooxygenases), resulting in lower concentrations of prostaglandins. As a consequence, inflammation, swelling, pain and fever are reduced. Fenoprofen was approved by the FDA in March 1976.

What brand names are available for fenoprofen?

Nalfon 200

Is fenoprofen available as a generic drug?


Do I need a prescription for fenoprofen?


What are the side effects of fenoprofen?

Common side effects include: 

NSAIDs reduce the ability of blood to clot and therefore increase bleeding after an injury. Fenoprofen also may cause stomach and intestinal bleeding and ulcers. Sometimes, stomach ulceration and intestinal bleeding may occur without any abdominal pain. Black tarry stools, weakness, and dizziness upon standing (orthostatic hypotension) may be the only signs of the bleeding.

People who are allergic to other NSAIDs should not use fenoprofen. NSAIDs reduce the flow of blood to the kidneys and impair function of the kidneys. The impairment is most likely to occur in patients with preexisting impairment of kidney function or congestive heart failure, and use of NSAIDs in these patients should be done cautiously. Individuals with asthma are more likely to experience allergic reactions to fenoprofen and other NSAIDs. Fluid retention, blood clots, heart attacks, high blood pressure (hypertension), and heart failure also have been associated with the use of NSAIDs.


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What is the dosage for fenoprofen?

The recommended adult dose for mild to moderate pain is 200 mg every 4-6 hours.

Rheumatoid arthritis and osteoarthritis are treated with 300 to 600 mg 3-4 times daily (every 6 to 8 hours). The maximum daily dose is 3200 mg daily.

Fenoprofen should be administered with meals in order to avoid stomach upset.

The safety and effectiveness of this drug in patients under age 18 has not been examined.

Which drugs or supplements interact with fenoprofen?

Fenoprofen is associated with several suspected or probable interactions that affect the action of other drugs. The following examples are the most commonly suspected interactions.

  • Fenoprofen may increase the blood levels of lithium (Eskalith, Lithobid) by reducing the excretion of lithium by the kidneys. Increased levels of lithium may lead to lithium toxicity.
  • Fenoprofen may reduce the blood pressure lowering effects of blood pressure medications. This may occur because prostaglandins play a role in the regulation of blood pressure.
  • When NSAIDs are used in combination with methotrexate (Rheumatrex, Trexall) or aminoglycosides (for example, gentamicin) the blood levels of the methotrexate or aminoglycoside may increase, presumably because their elimination from the body is reduced. This may lead to more methotrexate or aminoglycoside-related side effects.
  • Individuals taking oral blood thinners or anticoagulants, for example, warfarin, (Coumadin), should avoid fenoprofen because fenoprofen also thins the blood, and excessive blood thinning may lead to bleeding.
  • Persons who have more than three alcoholic beverages per day are at increased risk of developing stomach ulcers when taking fenoprofen or other NSAIDs.

Is fenoprofen safe to take if I'm pregnant or breastfeeding?

It is not known if fenoprofen is excreted in breast milk.

What else should I know about fenoprofen?

What preparations of fenoprofen are available?

Capsule: 200, 400 mg; Tablet: 600 mg

How should I keep fenoprofen stored?

Fenoprofen should be stored at room temperature, 20 C to 25 C (68 F to 77 F), in a sealed container to avoid moisture.


Fenoprofen (Nalfon) is a nonsteroidal antiinflammatory drug (NSAID) used for the treatment of pain and inflammation due to osteoarthritis and rheumatoid arthritis. Fenoprofen (Nalfon) is also used for the treatment of mild to moderate pain for conditions such as menstrual cramps, tendinitis, and bursitis. Side effects, drug interactions, warnings and precautions, and patient safety information should be reviewed prior to taking any medication.

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