Overview
DESCRIPTION Pentoxifylline extended-release tablets, USP for oral administration contain 400 mg of the active drug and the following inactive ingredients: colloidal silicon dioxide, hydroxypropyl cellulose, hypromellose, magnesium stearate, polyethylene glycol, and titanium dioxide in an extended-release formulation.
Mechanism of Action
CLINICAL PHARMACOLOGY Mode of Action Pentoxifylline and its metabolites improve the flow properties of blood by decreasing its viscosity. In patients with chronic peripheral arterial disease, this increases blood flow to the affected microcirculation and enhances tissue oxygenation. The precise mode of action of pentoxifylline and the sequence of events leading to clinical improvement are still to be defined. Pentoxifylline administration has been shown to produce dose-related hemorrheologic effects, lowering blood viscosity, and improving erythrocyte flexibility. Leukocyte properties of hemorrheologic importance have been modified in animal and in vitro human studies. Pentoxifylline has been shown to increase leukocyte deformability and to inhibit neutrophil adhesion and activation.
Indications
- INDICATIONS AND USAGE Pentoxifylline extended-release tablets are indicated for the treatment of patients with intermittent claudication on the basis of chronic occlusive arterial disease of the limbs. Pentoxifylline can improve function and symptoms but is not intended to replace more definitive therapy, such as surgical bypass, or removal of arterial obstructions when treating peripheral vascular disease.
Common Doses
- 400 mg
- 800 mg
- 30 mL
Dosage
DOSAGE AND ADMINISTRATION The usual dosage of pentoxifylline in extended-release tablet form is one tablet (400 mg) three times a day with meals. While the effect of pentoxifylline may be seen within 2 to 4 weeks, it is recommended that treatment be continued for at least 8 weeks. Efficacy has been demonstrated in double-blind clinical studies of 6 months duration. Digestive and central nervous system side effects are dose related. If patients develop these effects it is recommended that the dosage be lowered to one tablet twice a day (800 mg/day).
Contraindications
- CONTRAINDICATIONS Pentoxifylline should not be used in patients with recent cerebral and/or retinal hemorrhage or in patients who have previously exhibited intolerance to this product or methylxanthines such as caffeine, theophylline, and theobromine.
Side Effects
- ADVERSE REACTIONS Clinical trials were conducted using either extended-release pentoxifylline tablets for up to 60 weeks or immediate-release 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 to 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 pentoxifylline tablets, immediate-release pentoxifylline capsules, or the corresponding placebos.
Interactions
- Drug Interactions Bleeding has been reported in patients treated with pentoxifylline with or without concomitant NSAIDs, anticoagulants, or platelet aggregation inhibitors. Increased prothrombin time has been reported in patients concomitantly treated with pentoxifylline and vitamin K antagonists. Monitoring of anticoagulant activity in these patients is recommended when pentoxifylline is introduced or the dose is changed. Concomitant administration of pentoxifylline and theophylline-containing drugs leads to increased theophylline levels and theophylline toxicity in some individuals.