Its primary use in medicine is to reduce pain, cramping, numbness, or weakness in the arms or legs which occurs due to intermittent claudication, a form of muscle pain resulting from peripheral artery diseases.
This is its only FDA, MHRA and TGA-labelled indication.
Common side effects are belching, bloating, stomach discomfort or upset, nausea, vomiting, indigestion, dizziness, and flushing. Uncommon and rare side effects include angina, palpitations, hypersensitivity, itchiness, rash, hives, bleeding, hallucinations, arrhythmias, and aseptic meningitis.
Contraindications include intolerance to pentoxifylline or other xanthine derivatives, recent retinal or cerebral haemorrhage, and risk factors for haemorrhage.
Co-administration of pentoxifylline and sodium thiopental may cause death by acute pulmonary edema in rats.
Like other methylated xanthine derivatives, pentoxifylline is a competitive nonselective phosphodiesterase inhibitor
which raises intracellular cAMP, activates PKA, inhibits TNF
and leukotriene  synthesis, and reduces inflammation and innate immunity. In addition, pentoxifylline improves red blood cell deformability (known as a haemorrheologic effect), reduces blood viscosity and decreases the potential for platelet aggregation and thrombus formation.
Pentoxifylline is also an antagonist at adenosine 2 receptors.
Effect on seizure
In a study, the effect of pentoxifylline as a phosphodiestrase inhibitor was study on the pentylenetetrazol-induced seziure in the wild-type mice. Pentoxifylline in that study reduced the anti-convulsive effect of H-89 and reduced the seizure threshold.