Selegiline, also known as -deprenyl and sold under the brand names Eldepryl, Emsam, Selgin, among other names, is a medication which is used in the treatment of Parkinsons disease and major depressive disorder. It is provided in the form of a capsule or tablet taken by mouth or orally disintegrating tablets taken on the tongue for Parkinsons disease and as a patch applied to skin for depression.
Selegiline acts as a monoamine oxidase inhibitor, and increases levels of monoamine neurotransmitters in the brain. At typical clinical doses used for Parkinson's 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.