Selgin (generic selegiline hydrochloride) is a medication used to manage Parkinson's disease symptoms and may improve tremor and muscle stiffness when combined with levodopa/carbidopa therapy. The tablets should be stored at controlled room temperature, and contraindications include patients hypersensitive to selegiline and those using certain medications like MAO inhibitors and SSRIs. Side effects can include common reactions such as insomnia, dizziness, and increased dyskinesia, and overdose treatment is primarily symptomatic due to the lack of a specific antidote.