Epoetin theta treatment should be initiated by physicians experienced in the above-mentioned indications. Non-response to therapy with epoetin theta should prompt a search for causative factors. Deficiencies of iron, folic acid or vitamin B~12~ reduce the effectiveness of epoetins and should therefore be corrected. Intercurrent infections, inflammatory or traumatic episodes, occult blood loss, hemolysis, aluminium intoxication, underlying hematological diseases or bone marrow fibrosis may also compromise the erythropoietic response. A reticulocyte count should be considered as part of the evaluation. Pure red cell aplasia (PRCA) caused by neutralizing anti-erythropoietin antibodies has been reported in association with erythropoietin therapy. Epoetins are not approved in the management of anemia associated with hepatitis C. Patients on epoetin theta therapy can experience an increase in blood pressure or aggravation of existing hypertension particularly during the initial treatment phase (monitor closely and control blood pressure; a reduction of the administered dose of epoetin theta or temporary interruption of epoetin theta therapy may be required). Misuse of epoetin theta by healthy persons may lead to an excessive increase in hemoglobin and hematocrit (associated with life-threatening cardiovascular complications). The use of epoetin theta in nephrosclerotic patients not yet undergoing dialysis should be defined individually, as a possible accelerated progression of renal failure cannot be ruled out with certainty. During hemodialysis, patients treated with epoetin theta may require increased anticoagulation treatment to prevent clotting of the arterio-venous shunt. As with all growth factors, there is a concern that epoetins could stimulate the growth of any type of malignancy (in some clinical situations blood transfusion should be the preferred treatment for the management of anemia in patients with cancer. The decision to administer recombinant erythropoietins should be based on a benefit-risk assessment).