Beneficial results of pentoxifylline ('Trental') therapy in arteriosclerosis obliterans: possible mechanism of action.

A study was carried out in 17 patients with arteriosclerosis obliterans to assess the effectiveness of treatment with pentoxifylline ('Trental') and to investigate its possible mechanism of action. Patients received pentoxifylline on a combined intravenous/oral dosage regimen for 3 weeks and then were maintained on 800 mg orally for a further 2 weeks. The results showed that there was clinical improvement in 16 patients which was evident as a significant increase in the pain-free walking distance and blood flow in ischaemic legs, and the disappearance of rest pain. These changes were seen as soon as 1 week after the start of treatment. At the same time, an increase was observed in platelet sensitivity to the anti-aggregatory action of endogenous PGI2, as well as an activation of fibrinolysis in blood. After 5 weeks of treatment, further improvement was observed; however, platelets were no more hypersensitive to PGI2, and fibrinolytic activity of blood returned to the previous value. In experiments ex vivo, no release of a disaggregatory substance into blood was observed after a single bolus intravenous injection of pentoxifylline in patients with arteriosclerosis obliterans. It is concluded that the beneficial results of pentoxifylline therapy in such patients may be explained partially by a potentiation of the action of endogenous PGI2.