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Pentoxil Side Effects

Generic name: pentoxifylline

Medically reviewed by Last updated on Apr 26, 2023.

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

Applies to pentoxifylline: oral tablet extended release.

Serious side effects of Pentoxil

Along with its needed effects, pentoxifylline (the active ingredient contained in Pentoxil) 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 as soon as possible if any of the following side effects occur while taking pentoxifylline:


Signs and symptoms of overdose (in the order in which they may occur)

Other side effects of Pentoxil

Some side effects of pentoxifylline 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:

Less common

For Healthcare Professionals

Applies to pentoxifylline: compounding powder, oral tablet extended release.


Pentoxifylline (the active ingredient contained in Pentoxil) has been generally well tolerated. While typically minor, side effects have necessitated discontinuation of the drug in approximately 3% of treated patients. Tolerance to mild side effects generally has developed with continued use.[Ref]


Gastrointestinal side effects have been the most common side effects associated with pentoxifylline (the active ingredient contained in Pentoxil) therapy and have included dyspepsia, nausea, vomiting, and belching, which occurred in 1% to 3% of patients. Some smaller studies have reported gastrointestinal disturbance in up to 33% of patients treated with pentoxifylline.[Ref]

Nervous system

Nervous system side effects have occurred in 1% to 2% of treated patients and have included headache, dizziness, insomnia, and tremor. Some smaller studies have reported nervous system adverse effects in up to 17% of treated patients. In addition, rare cases of visual and auditory hallucinations have been reported. Aseptic meningitis has been reported in postmarketing experiences.[Ref]


Cardiovascular side effects have included reports of palpitations, flushing, and angina. These reports have usually been associated with higher doses of an immediate release capsule which is not available in the United States.[Ref]


Hematologic side effects have included anecdotal reports of pancytopenia and fatal aplastic anemia.[Ref]


Hepatic side effects have included postmarketing reports of cholestasis.


Hypersensitivity side effects have included postmarketing reports of anaphylactic reaction, anaphylactoid reaction, and anaphylactic shock.


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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.