Pentoxifylline Treatment in Patients with Occlusive Peripheral Arterial Disease. Circulatory Changes and Effects on Prostaglandin Synthesis

Pentoxifylline has recently been reported to stimulate in vitro the synthesis of prostacyclin. However it is not known so far whether the drug is able to stimulate prostacyclin synthesis in man also in vivo. In the present study the effects of pentoxifylline on prostaglandin synthesis and several circulatory pa rameters were studied in 10 controls and 10 patients with occlusive arterial disease after acute i.v. and medium term oral treatment. Prostacyclin (as 6- keto-PGF_1alpha) and PGE ₂ plasma concentrations have been measured together with arterial blood flow, peripheral vascular resistance, platelet aggregation and red blood cell deformability. Pentoxifylline was found both in healthy sub jects and patients to significantly increase prostacyclin plasma concentration after i.v. treatment. In medium term oral treatment prostacyclin concentration was found to increase only two hours after administration and not 8 hours after. No significant variations in PGE₂ plasma concentration were found at any time in both groups. Pentoxifylline significantly enhanced resting and post-ischemic blood flow of the lower limbs and simultaneously decreased peripheral vascular resistance both in healthy subjects and patients. Different grades of delayed platelet aggregation and increased red blood cell deformability were also ob served.

In conclusion results of the present placebo controlled study show that pen toxifylline increases arterial blood flow in patients with occlusive arterial dis ease. Moreover pentoxifylline induces a temporary stimulation of prostacyclin synthesis which can be suggested to contribute to the clinical activity of the drug as far as an antithrombotic effect in terms of inhibition of platelet aggregation is concerned.