Emsam Active ingredient: selegiline $0.97 for pill Emsam is used to treat adult patients with depression, also known as major depressive disorder (MDD). Eldepryl Active ingredient: selegiline $0.68 for pill Eldepryl is used in combination with levodopa or levodopa and carbidopa combination to treat Parkinson's disease (sometimes called shaking palsy or paralysis agitans). This medicine works to increase and extend the effects of levodopa, and may help to slow the progress of Parkinson's disease.