Side Effects of Trental (pentoxifylline)

Trental (pentoxifylline) is a hemorrheologic agent (a drug that affects blood viscosity) used to treat symptoms of intermittent claudication caused by peripheral arterial disease (PAD).

Common side effects of Trental include

• nausea,
• vomiting,
• dizziness,
• headache,
• diarrhea,
• blurred vision,
• agitation,
• insomnia and
• drowsiness.

Serious side effects of Trental include

• abnormal heart beats,
• elevation of liver function tests,
• yellowing skin and eyes (jaundice), and
• hepatitis.

Drug interactions of Trental include theophylline, because Trental reduces its breakdown in the liver, increasing blood levels and side effects of theophylline. Combining Trental with warfarin may increase the risk of bleeding.

Trental has not been adequately studied in pregnant women. Trental is excreted in breast milk and may cause adverse effects in the infant. Consult your doctor before breastfeeding. 

Common adverse effects include:

• nausea,
• vomiting,
• dizziness,
• headache,
• diarrhea,
• blurred vision,
• agitation,
• insomnia and
• drowsiness.

Other side effects include:

• abnormal
• heart beats,
• elevation of
• liver function tests,
• jaundice, and
• hepatitis.

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.

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

Drug-Drug Interactions

Antacids: In patients with digestive side effects, antacids may be administered with Trental. In comparative bioavailability study, no interference with absorption of Trental by antacids was observed.

Antihypertensive agents: Trental (pentoxifylline) may potentiate the action of antihypertensive agents. Patients receiving these agents require blood pressure monitoring and possibly a dose reduction of the antihypertensive agents.

Anticoagulants: There have been reports of bleeding and/or prolonged prothrombin time in patients treated with Trental with and without anticoagulants, including vitamin K antagonists, or platelet aggregation inhibitors. Monitoring of anti-coagulant activity in these patients is recommended when pentoxifylline is introduced or the dose is changed.

Patients on warfarin should have more frequent monitoring of prothrombin time, while patients with other risk factors complicated by hemorrhage (e.g. recent surgery) should have periodic examinations for signs of bleeding, including hematocrit and haemoglobin.

Cimetidine: During concurrent use of cimetidine and pentoxifylline, cimetidine has been shown to significantly increase the steady-state plasma concentration of pentoxifylline, which may enhance the possibility of adverse effects.

Erythromycin: No data are available on the possible interaction of Trental and erythromycin. However concurrent administration of erythromycin and theomycin has resulted in significant elevation of serum theophylline levels with toxic reactions.

Hypoglycemic agents: The blood-sugar lowering effect of insulin or oral antidiabetic agents may be potentiated. In patients treated with hypoglycemic agents, a moderate adjustment in the dose of these agents may be required when Trental is prescribed. Therefore it is recommended that patients under medication for diabetes mellitus be carefully monitored

Sympathomimetics: Combined use with other xanthines or with sympathomimetics may cause excessive CNS stimulation.

Theophylline: Although causality has not been established, concurrent use of pentoxifylline with theophylline has resulted in elevated theophylline plasma levels, which may enhance the possibility of adverse effects.

Drug-Food Interactions

Interactions with food have not been established.

Drug-Herb Interactions

Interactions with herbal product have not been established.

Drug-Laboratory Interactions

Interactions with laboratory tests have not been established.

Drug-Lifestyle Interactions

Interactions with lifestyles have not been established.