Aim. Atherosclerotic peripheral arterial disease is a major health problem in the western world, often manifested as intermittent claudication, affecting 10-20% males above 60 years. Ischemic complications can lead to rest pain, ulceration and gangrene. The treatment of choice for critical limb ischemia (CLI) is vascular reconstruction or endovascular interventions. Medical management with vasodilator antiplatelet prostaglandins, could be considered in patients unsuitable for surgery. Long term follow-up on previous prostaglandin studies has been insufficient to evaluate amputation rates. Hence this study evaluated safety and longer term efficacy of taprostene sodium, a prostacyclin (PGI2) analogue in CLI. The aim of this study was to determine whether Taprostene sodium, a PGI2 analogue, was a safe and effective treatment for CLI. Methods. This paper reports the data from the Scottish-Finnish-Swedish PARTNER Study Group which consisted of a double-blind placebo controlled multi-centre study evaluating Taprostene compared to placebo. The primary endpoints were pain relief and early ulcer healing response at the end of the four week infusion phase and amputation at six months follow-up. The patients were randomly allocated to receive taprostene or placebo in a two to one randomization of active versus placebo. A total of 111 patients with CLI were recruited. Taprostene was given twice a day over two 2 hour periods for four weeks. The early response was evaluated at the end of the four week infusion phase. In patients with rest pain without ulceration, a positive response was complete pain relief without any requirement for analgesic therapy. However in patients with ulceration, a positive response was defined as a decrease in the ulcer size by >30%. Amputation scores were compared at the end of the 6 months follow-up period for all participants. Results. Seventy-four patients received taprostene and 37 placebo. Overall, 61 male patients were enrolled in the study along with 50 females with 11% more women in the taprostene (active) group. For both patients with and without ulcers there was no statistically significant difference noted in the early response between those receiving taprostene and those receiving placebo infusion. The percentage of patients without any amputations was 43% in the taprostene group compared to 38% in the control group at the end of six months; however, these results were not statistically significant. Conclusion. Although a reasonable number of patients enrolled in the study it has not been possible to demonstrate any statistically significant benefit of taprostene over placebo. This may be due to more patients with risk factors for peripheral artery disease (PAD) such as hypertension, diabetes mellitus and cigarette smoking in the actively treated group and also due the increased number of women in the active group who are known to generally respond less favourably to antiplatelet agents.