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Nalfon Side Effects

Generic name: fenoprofen

Medically reviewed by Last updated on Nov 1, 2023.

Note: This document contains side effect information about fenoprofen. Some dosage forms listed on this page may not apply to the brand name Nalfon.

Applies to fenoprofen: oral capsule, oral tablet.


Oral route (Capsule)

NSAIDs cause an increased risk of serious cardiovascular thrombotic events, including myocardial infarction and stroke, which can be fatal. This risk may occur early in treatment and may increase with duration of use. Fenoprofen is contraindicated in the setting of CABG surgery. NSAIDs also cause an increased risk of serious gastrointestinal (GI) adverse events, including bleeding, ulceration, and perforation of the stomach or intestines, which can be fatal. These events can occur at any time during use and without warning symptoms. Elderly patients and patients with a prior history of peptic ulcer disease and/or GI bleeding are at greater risk for serious GI events.

Serious side effects of Nalfon

Along with its needed effects, fenoprofen (the active ingredient contained in Nalfon) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking fenoprofen:

Less common


Symptom of overdose

Other side effects of Nalfon

Some side effects of fenoprofen may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

Less common


For Healthcare Professionals

Applies to fenoprofen: compounding powder, oral capsule, oral tablet.


The most frequently reported side effects were dyspepsia, headache, somnolence, nausea, dizziness, constipation, nervousness, asthenia, and peripheral edema.[Ref]


Very common (10% or more): Dyspepsia (10.3%)

Common (1% to 10%): Nausea, constipation, vomiting, abdominal pain, diarrhea

Frequency not reported: Gastritis, peptic ulcer, peptic ulcer with perforation, gastrointestinal (GI) hemorrhage, GI bleeding, flatulence, dry mouth, blood in stool, buccal mucosa aphthous ulcerations, pancreatitis, burning tongue, melena, hematemesis, ulcerative stomatitis, Crohn's disease exacerbated, colitis exacerbated[Ref]


Common (1% to 10%): Palpitations

Frequency not reported: Atrial fibrillation, electrocardiographic changed, supraventricular tachycardia, tachycardia, hypertension, cardiac failure[Ref]


Frequency not reported: Renal failure, cystitis, azotemia, interstitial nephritis, nephrosis, papillary necrosis, nephrotoxicity, nephrotic syndrome[Ref]


Frequency not reported: Dysuria, hematuria, oliguria, anuria, mastodynia, breast pain[Ref]


Frequency not reported: SGOT/AST increased, jaundice, cholestatic hepatitis, abnormal liver function[Ref]


Common (1% to 10%): Dyspnea, upper respiratory infection, nasopharyngitis

Frequency not reported: Pulmonary edema[Ref]

Nervous system

Common (1% to 10%): Headache, somnolence, dizziness, tremor

Frequency not reported: Taste metallic, seizure, trigeminal neuralgia, paresthesia, drowsiness[Ref]


Common (1% to 10%): Confusion, nervousness

Frequency not reported: Depression, disorientation, insomnia, personality changed, hallucinations[Ref]


Common (1% to 10%): Sweating increased, pruritus, rash

Frequency not reported: Angioedema, purpura, bruising, exfoliative dermatitis, toxic epidermal necrolysis, Stevens-Johnson syndrome, alopecia, urticaria, photosensitivity, sweating increased[Ref]


Frequency not reported: Hypersensitivity reaction[Ref]


Frequency not reported: Anaphylaxis[Ref]


Frequency not reported: Hemorrhage, thrombocytopenia, hemolytic anemia, aplastic anemia, agranulocytosis, pancytopenia, lymphadenopathy, neutropenia[Ref]


Common (1% to 10%): Tinnitus, decreased hearing, asthenia, peripheral edema, fatigue

Frequency not reported: Alkaline phosphatase increased, LDH increased, malaise, fever, aseptic meningitis, tinnitus, hearing decreased, vertigo, aseptic meningitis[Ref]


Common (1% to 10%): Vision blurred

Frequency not reported: Diplopia, optic neuritis, vision disturbed, optic neuritis, amblyopia, diplopia[Ref]


Frequency not reported: Anorexia[Ref]


1. Product Information. Nalfon (fenoprofen). Xspire Pharma. 2002;PROD.

2. MHRA. Medicines and Health Regulatory Agency. MHRA Drug Safety Update. 2013.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.