Selegiline is a medication which is used in the treatment of Parkinsons disease and major depressive disorder.
It acts as a monoamine oxidase inhibitor, and increases levels of monoamine neurotransmitters in the brain. At typical clinical doses used for Parkinsons disease, selegiline is a selective and irreversible inhibitor of monoamine oxidase B (MAO B), increasing levels of dopamine in the brain. In larger doses (more than 20 mg/day), it loses its specificity for MAO B and also inhibits MAO A, which increases serotonin and norepinephrine levels in the brain.
Selegiline has also been used off label as a palliative treatment for dementia in Alzheimers disease and is also used as a treatment for major depressive disorder.
