[Thrombopenia caused by pentosan polysulfate]

Two case-reports of thrombopenias induced by pentosane polysulfate (PSP) are reported. PSP may play a direct role in the genesis of the thrombopenia appearing between the 5th and 15th day of treatment, or a sensitizing role where the thrombopenia occurs quite rapidly following heparin treatment. The clinical complications are haematomas, arterial or venous thromboses and haemorrhages. The platelet aggregation test is always positive in the presence of PSP. The immunological origin is probable. Monitoring of the platelet count is recommanded with this treatment.