Selegiline is used to help control the symptoms of Parkinson's disease (PD; a disorder of the nervous system that causes difficulties with movement, muscle control, and balance) in people who are taking levodopa and carbidopa combination (Sinemet). Chemically known as selegiline or L-deprenyl, it is an irreversible monoamine oxidase B inhibitor that, at therapeutic doses, preferentially blocks MAO-B to reduce oxidative breakdown of dopamine and thereby augment dopaminergic neurotransmission in the striatum. The drug exhibits oral bioavailability limited by first-pass metabolism, undergoes hepatic biotransformation to active and inactive metabolites including levobamphetamine and levo-methamphetamine isomers, and is cleared primarily via renal excretion of metabolites. Clinically selegiline is used as adjunctive therapy to prolong and smooth levodopa efficacy, reduce motor fluctuations, and may delay dose escalation of levodopa; its pharmacodynamic profile includes potential interactions with serotonergic and sympathomimetic agents and dose-dependent loss of MAO-B selectivity.
Parent: Selegiline
Parent: Selegiline
Parent: Selegiline
Parent: Selegiline
Parent: Selegiline
Parent: Selegiline/ Selegiline Hydrochloride
Commercial selegiline active pharmaceutical ingredient and finished product specifications typically monitor related substances, metabolic analogs, and residual process solvents; identified related compounds include N-desmethylselegiline, N-propargyl derivatives, and trace amounts of amphetamine and methamphetamine isomers that may arise as metabolites or minor byproducts. Typical analytical limits set in regulatory and pharmacopeial specifications keep individual unspecified impurities at or below about 0.05 to 0.10 percent w/w and total impurities below about 0.5 percent w/w, with amphetamine/methamphetamine related compounds commonly controlled to low ppm levels, for example below 500 ppm or often below 100 ppm depending on the product specification and regional regulatory expectations. Residual solvents are controlled per ICH Q3C limits, for example methanol up to 3000 ppm as a class 2 solvent when applicable, and elemental impurities are restricted per ICH Q3D guidance; manufacturers provide a validated impurity profile and stability data to ensure impurity levels remain within accepted limits throughout product shelf life.
Selegiline is used as adjunctive therapy in Parkinson’s disease to enhance and prolong the effects of levodopa/carbidopa therapy, reduce motor fluctuations, and support dopaminergic tone by inhibiting MAO-B; it is not typically used as monotherapy for advanced PD.
Selegiline is selective for MAO-B at standard therapeutic doses, producing preferential inhibition of MAO-B over MAO-A; however, selectivity is dose dependent and higher doses or certain formulations can reduce selectivity and increase the risk of interactions related to MAO-A inhibition.
Avoid concomitant use of certain serotonergic agents such as SSRIs, SNRIs, tricyclic antidepressants, meperidine, and other MAO inhibitors because of the risk of serotonin syndrome or hypertensive reactions; also exercise caution with sympathomimetics and, depending on dose and formulation, limit intake of high-tyramine foods; always consult prescribing information and a clinician before starting or stopping other medications.
Selegiline itself is not classified as a stimulant, but it is metabolized to levobamphetamine and levo-methamphetamine which can produce mild stimulant-like effects in some patients such as insomnia, agitation, or increased heart rate; these effects are generally dose dependent and more likely with higher systemic exposure.
