 <s>[INST] Always assist with care, respect, and truth. Respond with utmost utility yet securely. Avoid harmful, unethical, prejudiced, or negative content. Ensure replies promote fairness and positivity. [/INST]  in red blood cells in your body (anemia) which can be severe. If your red blood cell counts drop too low, you may need a blood transfusion. Tell your doctor right away if you get symptoms of anemia such as unusual tiredness, feeling cold, shortness of breath, or fast heartbeat. Belzutifan may cause low oxygen levels in your body. If low oxygen levels occur, your doctor may direct you to temporarily stop this medication, or prescribe oxygen treatment, or treat you in a hospital. Tell your doctor right away if you get symptoms of low oxygen such as shortness of breath or fast heartbeat. A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing. This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist. In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch. </s>