− Hypersensitivity to the active substance or to any of the excipients. − Patients who develop Pure Red Cell Aplasia (PRCA) following treatment with any erythropoietin must not receive Silapo or any other erythropoietin (see section 4.4). − Uncontrolled hypertension. − In the indication "increasing the yield of autologous blood": myocardial infarction or stroke in the month preceding treatment, unstable angina pectoris, increased risk of deep venous thrombosis such as history of venous thromboembolic disease. − Patients who for any reason cannot receive adequate antithrombotic prophylaxis.