 <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]  or get worse, tell your doctor or pharmacist promptly. Many people using this medication may have serious side effects. However, you have been prescribed this drug because your doctor has judged that the benefit to you is greater than the risk of side effects. Careful monitoring by your doctor may decrease your risk. Tell your doctor right away if you have any serious side effects, including: signs of liver disease (such as nausea/vomiting that doesn't stop, severe stomach/abdominal pain, yellowing skin/eyes, dark urine), seizures, unusual/extreme tiredness, painful urination, toe/joint pain, fainting, fast/pounding heartbeat, cloudy/blurred vision. Busulfan has rarely caused very serious (possibly fatal) lung disease. This may occur after months to years of using busulfan. Tell your doctor right away if you develop symptoms of lung disease, including cough that doesn't go away, chest pain, shortness of breath. Busulfan may cause other cancers (such as acute leukemia, tumors). Consult your doctor for more details. Tell your doctor right away if you notice any symptoms of cancer, including unusual lumps, sudden weight loss. A very serious allergic reaction to this drug is rare. </s>