August 23, 2016


Trental Side Effects Center

Medical Editor: John P. Cunha, DO, FACOEP

Last reviewed on RxList 5/15/2015

Trental (pentoxifylline) is a hemorrheologic agent (an agent that affects blood viscosity) used to improve blood flow. Improved blood flow helps reduce leg cramps and other symptoms of vascular disease (disease related to veins and arteries). Trental is available in generic form. Common side effects of Trental include nausea, vomiting, gas, bloating, belching, upset stomach, diarrhea, dizziness, headache, blurred vision, or flushing (warmth, redness, or tingly feeling). Tell your doctor if you have serious side effects of Trental including chest pain, feeling like you might pass out, red or pink urine, bloody or tarry stools, or coughing up blood or vomit.

The usual dosage of Trental in extended-release tablet form is one tablet (400 mg) three times a day with meals. It is recommended treatment is continued for at least 8 weeks. Trental may interact with blood thinners, theophylline, aminophylline, dyphylline, and oxtriphylline. Tobacco may worsen your condition or decrease the beneficial effects of Trental by narrowing your blood vessels. Talk to your doctor if you use tobacco. Tell your doctor all medications you use. During pregnancy, Trental should be used only when prescribed. This medication passes into breast milk. Consult your doctor before breast-feeding.

Our Trental (pentoxifylline) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What is Patient Information in Detail?

Easy-to-read and understand detailed drug information and pill images for the patient or caregiver from Cerner Multum.

Trental in Detail - Patient Information: Side Effects

Stop taking this medication and get emergency medical help if you have any of these signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have a serious side effect such as:

  • chest pain,
  • pounding heartbeats or fluttering in your chest;
  • feeling like you might pass out;
  • red or pink urine;
  • bloody, black, or tarry stools; or
  • coughing up blood or vomit that looks like coffee grounds.

Less serious side effects may include:

  • dizziness, headache;
  • blurred vision;
  • flushing (warmth, redness, or tingly feeling);
  • gas, bloating, upset stomach; or
  • nausea, vomiting, diarrhea.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088. You may report side effects to FDA at 1-800-FDA-1088.

Read the entire detailed patient monograph for Trental (Pentoxifylline)

What is Patient Information Overview?

A concise overview of the drug for the patient or caregiver from First DataBank.

Trental Overview - Patient Information: Side Effects

SIDE EFFECTS: Nausea, vomiting, gas, belching, and dizziness may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor immediately if any of these rare but very serious side effects occur: fast/irregular heartbeat, easy bruising/bleeding.

Seek immediate medical attention if this rare but very serious side effect occurs: chest pain.

A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US -

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Read the entire patient information overview for Trental (Pentoxifylline)

What is Prescribing information?

The FDA package insert formatted in easy-to-find categories for health professionals and clinicians.

Trental FDA Prescribing Information: Side Effects
(Adverse Reactions)


Clinical Trial Adverse Drug Reactions

Because clinical trials are conducted under very specific conditions the adverse reaction rates observed in the clinical trials may not reflect the rates observed in practice and should not be compared to the rates in the clinical trials of another drug. Adverse drug reaction information from clinical trials is useful for identifying drug-related adverse events and for approximating rates.

The most frequent adverse event reported with Trental (pentoxifylline) is nausea (14%). Individual signs/symptoms listed in the table below occurred at an incidence between 1 and 3%, except when stated otherwise.

Body as a whole Malaise
Cardiovascular system Flushing
Central nervous system Dizziness/light-headedness (9.4%), headache (4.9 %)
Gastrointestinal system Nausea (14%), vomiting (3.4%), abdominal discomfort, bloating, diarrhea, dyspepsia

Less Common Clinical Trial Adverse Drug Reactions ( < 1%)

Body as a whole: Muscle aches/spasm, weight change, backache, bad taste in mouth, leg cramps, fever, weakness, sweating.

Cardiovascular: Chest pain, arrhythmia, hypertension, dyspnea, edema, hypotension, angina, tachycardia.

Central nervous system: Drowsiness/sleepiness, tremor, agitation anxiety, confusion, insomnia, restlessness.

Gastrointestinal: Abdominal burning, abdominal pain, anorexia flatus, constipation, haemorrhage, heartburn, salivation, dry mouth/throat, hepatitis, jaundice, increased liver enzymes.

Hemic and lymphatic: Decreased serum fibrinogen, pancytopenia, purpura, thrombocytopenia, leucopenia, anemia, aplastic anemia.

Hypersensitivity reactions: Pruritis, rash, urticaria, angioedema.

Organs of special sense: Blurred vision, scotoma, lacrimation, epistaxis.

Post-Market Adverse Drug Reactions

Hepatobiliary disorders: Intrahepatic cholestasis.

Immune system disorders: Severe anaphylactic/anaphylactoid reaction with, for example, angioneurotic edema, bronchospasms, sometimes shock.

Infections and infestations: Aseptic meningitis.

Investigations: Transaminase elevation.

Psychiatric: Sleep disturbances.

Skin and subcutaneous tissue disorders: Reddening of skin.

Vascular disorder: Haemorrhage

Read the entire FDA prescribing information for Trental (Pentoxifylline)

Trental - User Reviews

Trental User Reviews

Now you can gain knowledge and insight about a drug treatment with Patient Discussions.

Here is a collection of user reviews for the medication Trental sorted by most helpful. Patient Discussions FAQs

Report Problems to the Food and Drug Administration


You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

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