[Severe thrombopenia associated with treatment with pentosan polysulfate]

Two cases of severe thrombocytopaenia associated with acute thrombo-embolic manifestations during treatment by pentosan polysulphate, a low molecular weight heparinoid, are reported. Plasma samples from both patients caused in vitro aggregation in the presence of pentosan polysulphate. Interruption of the drug led to the recovery of the platelet count. The hypothesis of an immunoallergic mechanism similar to heparin associated thrombocytopaenia is supported. Furthermore, it seemed likely to be found with all the polysulphated X glycosaminoglycans. During treatment by pentosan polysulphate, platelet count should be monitored to avoid this potentially life-threatening syndrome.