Derbaset 40 PFS Injection 0.4 ml is used to treat anaemia (low red blood cell count) in person with long-term serious (chronic) kidney disease and persons receiving chemotherapy for some types of cancer (except for bone marrow or blood cells' cancer). It helps to reverse anaemia and reduce the need for blood transfusion. It contains Darbepoetin alfa, which works by providing signals to the bone marrow to make more red blood cells. In chronic kidney disease, when the kidney fails to produce sufficient erythropoietin protein that aids in the formation of red blood cells, this medicine stimulates the production of this protein in the bone marrow. It may cause common side effects such as shortness of breath, cough, low blood pressure during dialysis, headache, body aches, diarrhoea, injection site pain and abdominal pain.