 <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] stradefylline Oral: Istradefylline is used by people with Parkinson's disease taking carbidopa/levodopa to reduce the amount of "off" time (periods of slow movement or stiffness). How to use Istradefylline 40 Mg Tablet Take this medication by mouth with or without food as directed by your doctor, usually once daily. The dosage is based on your medical condition, response to treatment, and other medications you may be taking. Be sure to tell your doctor and pharmacist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products). Do not increase your dose or take it more often than prescribed. Your condition will not improve any faster, and your risk of side effects will increase. Tell your doctor if this medication stops working well or if your condition gets worse.The side effects of Istradefylline Oral: Dizziness, decreased appetite, or constipation may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly. Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects </s>