 <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] This medication may not cure your cancer. Delaying surgery could lead to a more serious illness (metastatic cancer). Discuss the risks and benefits of this medication with your doctor. How to use Valstar Vial This medication is given by placement into the bladder as directed by your doctor, usually once weekly for 6 weeks. Do not give by injection into a vein or muscle or under the skin. After this medication is placed through a tube (catheter), it is usually left in the bladder for 2 hours, then released by urinating. Drink plenty of fluids after each treatment with this medication unless otherwise directed by your doctor. Doing so helps clear it from your body and decrease side effects.The side effects of Valstar Intravesical: Bladder irritation, with symptoms such as pain, spasm, and frequent urge to urinate, usually occurs. This medication usually will cause your urine to turn a reddish color. This is a normal, harmless effect of the drug and should not be mistaken for blood in your urine. If any of these effects last or get worse after 24 hours, tell your doctor right away. Infrequent side effects include nausea, abdominal/stomach pain, diarrhea, headache, weakness, dizziness, or back pain. If any </s>