Selegiline

Here is some additional info:"This medication is used to treat movement disorders caused by Parkinson's disease. It does not cure Parkinson's disease, but it may improve shakiness (tremor), muscle stiffness, loss of normal movement as your dose of other Parkinson's medication wears off (end-of-dose failure), and sudden switching between normal movement and stiffness ("on-off" problems). It may improve your range of motion and ability to walk, dress, and exercise. Selegiline is usually used in combination with other medicines (e.g., levodopa, carbidopa).
Selegiline is an enzyme blocker (MAO inhibitor) that works by slowing the breakdown of certain natural substances in the brain (neurotransmitters such as dopamine, norepinephrine, and serotonin).How to use Selegiline
Take this medication by mouth, usually twice daily with breakfast and lunch. Taking selegiline late in the day may cause trouble sleeping. Dosage is based on your medical condition and response to therapy. The usual highest dose is 5 milligrams twice a day. 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.
Dizziness, abdominal pain, dry mouth, nausea, stomach upset, trouble sleeping, and headache may occur. If any of these effects persist or worsen, notify your doctor or pharmacist promptly.
If you are also taking levodopa, you may experience more side effects from the levodopa when taking selegiline. Tell your doctor immediately if any of these side effects occur: nausea, shakiness, muscle stiffness, mental/mood changes such as hallucinations/abnormal dreams. Your doctor may need to change your medication or dose. Do not stop or change the dose of your levodopa without talking with your doctor first.
Remember that your doctor has prescribed this medication because the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
Tell your doctor immediately if any of these unlikely but serious side effects occur: fainting, loss of balance, mental/mood changes (e.g., agitation, confusion, depression, hallucinations), worsening muscle stiffness/twitching, changes in sexual ability/interest, increased shaking (tremor), swollen ankles/legs, difficulty urinating, unusual weight gain.
Tell your doctor immediately if any of these rare but very serious side effects occur: easy bleeding/bruising, black/tarry stools, vomit that looks like coffee grounds.
This drug may rarely cause an attack of extremely high blood pressure (hypertensive crisis), which may be fatal. Many drug and food interactions can increase this risk. (See also Drug Interactions section.) Seek immediate medical attention if any of these serious side effects occur: frequent/severe headache, fast/slow/irregular/pounding heartbeat, chest pain, neck stiffness/soreness, severe nausea/vomiting, sweating/clammy skin (sometimes with fever), widened pupils, vision changes (e.g., double/blurred vision)., sudden sensitivity to light (photophobia).
A serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction include: rash, itching, swelling, dizziness, trouble breathing.
If you notice other effects not listed above, contact your doctor or pharmacist."

Source :PatientsLikeMe