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Trental Side Effects

Generic Name: pentoxifylline

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

For the Consumer

Applies to pentoxifylline: oral tablet extended release

Along with its needed effects, pentoxifylline (the active ingredient contained in Trental) 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:

  • Chest pain
  • irregular heartbeat
Signs and symptoms of overdose (in the order in which they may occur)
  • Drowsiness
  • flushing
  • faintness
  • unusual excitement
  • convulsions (seizures)

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 Trental) 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 Trental) 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.


1. "Product Information. Trental (pentoxifylline)." Hoechst Marion-Roussel Inc, Kansas City, MO.

2. Dettelbach HR, Aviado DM "Clinical pharmacology of pentoxifylline with special reference to its hemorrheologic effect for the treatment of intermittent claudication." J Clin Pharmacol 25 (1985): 8-26

3. Witter FR, Smith RV "The excretion of pentoxifylline and its metabolites into human breast milk." Am J Obstet Gynecol 151 (1985): 1094-7

4. Green RM, McNamara J "The effects of pentoxifylline on patients with intermittent claudication." J Vasc Surg 7 (1988): 356-62

5. Ward A, Clissold SP "Pentoxifylline: a review of its pharmacodynamic and pharmacokinetic properties, and its therapeutic efficacy." Drugs 34 (1987): 50-97

6. Lucas MA "Prevention of post-operative thrombosis in peripheral arteriopathies. Pentoxifylline vs. conventional antiaggregants: a six-month randomized follow-up study." Angiology 35 (1984): 443-50

7. Baker DE, Campbell RK "Pentoxifylline: a new agent for intermittent claudication." Drug Intell Clin Pharm 19 (1985): 345-8

8. Crowder JE, Cohn JB, Savitsky JP, Morgan DL, Slywka J, Cobert BL, Hryniewicki SW, Piccirillo RT, Wilcox CS "Efficacy and safety of pentoxifylline in geriatric patients with intermittent claudication." Angiology 40 (1989): 795-802

9. Pitner J, Simpson W, Gutierrez S, Mintzer J "Pentoxifylline (Trental)-induced visual hallucinations." J Am Geriatr Soc 41 (1993): 782-3

10. Gilbert GJ "Pentoxifylline-induced musical hallucinations." Neurology 43 (1993): 1621-2

11. Mass RD, Venook AP, Linker CA, Zipkin RE "Pentoxifylline and aplastic anemia." Ann Intern Med 107 (1987): 427-8

Some side effects of Trental may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

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