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Clinical trials were conducted using either extended-release TRENTAL (pentoxifylline) tablets for up to 60 weeks or immediate-release TRENTAL (pentoxifylline) capsules for up to 24 weeks. Dosage ranges in the tablet studies were 400 mg bid to tid and in the capsule studies, 200-400 mg tid. The table summarizes the incidence (in percent) of adverse reactions considered drug related, as well as the numbers of patients who received extended-release TRENTAL (pentoxifylline) tablets, immediate-release TRENTAL (pentoxifylline) capsules, or the corresponding placebos. The incidence of adverse reactions was higher in the capsule studies (where dose related increases were seen in digestive and nervous system side effects) than in the tablet studies. Studies with the capsule include domestic experience, whereas studies with the extended-release tablets were conducted outside the U.S.

The table indicates that in the tablet studies few patients discontinued because of adverse effects.

INCIDENCE (%) OF SIDE EFFECTS

TRENTAL (pentoxifylline) has been marketed in Europe and elsewhere since 1972. In addition to the above symptoms, the following have been reported spontaneously since marketing or occurred in other clinical trials with an incidence of less than 1%; the causal relationship was uncertain:

Cardiovascular - dyspnea, edema, hypotension.

Digestive - anorexia, cholecystitis, constipation, dry mouth/thirst.

Nervous - anxiety, confusion, depression, seizures, aseptic meningitis.

Respiratory - epistaxis, flu-like symptoms, laryngitis, nasal congestion.

Skin and Appendages - brittle fingernails, pruritus, rash, urticaria, angioedema.

Special Senses - blurred vision, conjunctivitis, earache, scotoma.

Miscellaneous - bad taste, excessive salivation, leukopenia, malaise, sore throat/swollen neck glands, weight change.

A few rare events have been reported spontaneously worldwide since marketing in 1972. Although they occurred under circumstances in which a causal relationship with pentoxifylline could not be established, they are listed to serve as information for physicians. Cardiovascular — angina, arrhythmia, tachycardia, anaphylactoid reactions. Digestive — hepatitis, jaundice, increased liver enzymes; and Hemic and Lymphatic — decreased serum fibrinogen, pancytopenia, aplastic anemia, leukemia, purpura, thrombocytopenia.

Although a causal relationship has not been established, there have been reports of bleeding and/or prolonged prothrombin time in patients treated with TRENTAL (pentoxifylline) with and without anticoagulants or platelet aggregation inhibitors. Patients on Warfarin should have more frequent monitoring of prothrombin times, while patients with other risk factors complicated by hemorrhage (e.g., recent surgery, peptic ulceration) should have periodic examinations for bleeding including hematocrit and/or hemoglobin. Concomitant administration of TRENTAL (pentoxifylline) and theophylline-containing drugs leads to increased theophylline levels and theophylline toxicity in some individuals. Such patients should be closely monitored for signs of toxicity and have their theophylline dosage adjusted as necessary. TRENTAL (pentoxifylline) has been used concurrently with antihypertensive drugs, beta blockers, digitalis, diuretics, antidiabetic agents, and antiarrhythmics, without observed problems. Small decreases in blood pressure have been observed in some patients treated with TRENTAL (pentoxifylline) ; periodic systemic blood pressure monitoring is recommended for patients receiving concomitant antihypertensive therapy. If indicated, dosage of the antihypertensive agents should be reduced.

Last reviewed on RxList: 3/16/2009
This monograph has been modified to include the generic and brand name in many instances.