 <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]  that works by slowing the breakdown of certain natural substances in the brain (neurotransmitters such as dopamine, norepinephrine, and serotonin). How to use selegiline oral Take this medication by mouth as directed by your doctor, usually twice daily with breakfast and lunch. Taking selegiline late in the day may cause trouble sleeping. The dosage is based on your medical condition and response to treatment. Do not increase your dose or take it more often than directed. After you have been taking selegiline for 2 or 3 days, your doctor may direct you to lower your levodopa dose. Follow your doctor's instructions closely. Do not stop or change the dose of any of your medications without first talking with your doctor. It may take a few weeks for the full benefits of the drug to be noticed. Do not stop taking this drug without first consulting your doctor. Talk with your doctor if the medication stops working well or if your condition worsens.The side effects of Selegiline Oral: Dizziness, abdominal pain, dry mouth, nausea, stomach upset, trouble sleeping, and headache may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly. To reduce the risk of dizz </s>