Adult: As conventional preparation: 10 mg daily, either as a single dose (in the morning) or in 2 divided doses of 5 mg (at breakfast and lunchtime). As oral lyophilisate tab: Initially, 1.25 mg daily.
Transdermal Depression
Adult: Initially, 6 mg daily, may increase in increments of 3 mg/24 hr every 2 weeks. Max: 12 mg/24 hr. Patches should be changed every 24 hours and new patch is applied to a different site. (Patient on doses ≥9 mg/24 hr should restrict intake of tyramine-rich foods during and for 2 weeks after treatment discontinuation. Elderly: ≥65 yr 6 mg/24 hr.
Administration
Should be taken with food.
Contraindications
Active duodenal or gastric ulcer. Concomitant use w/ serotonin agonists (e.g. sumatriptan, zolmitriptan), pethidine and other opioids, antidepressants (including TCAs, MAOIs, SSRIs, serotonin norepinephrine reuptake inhibitors), St John’s wort.
Special Precautions
Patient w/ uncontrolled HTN, angina, arrhythmias, psychosis, history of peptic ulcer and those at risk of orthostatic hypotension. Severe hepatic or renal impairment. Elderly. Pregnancy and lactation.
May increase risk of hypertensive reactions w/ dopamine. May increase bioavailability w/ OCs or drugs for hormone replacement therapy. Potentially Fatal: May cause severe serotonin syndrome w/ antidepressants (including TCAs, MAOIs, SSRIs, serotonin norepinephrine reuptake inhibitors), serotonin agonists (e.g. sumatriptan, zolmitriptan). May cause resp depression and hypotension w/ pethidine and other opioids.
Food Interaction
May cause severe serotonin syndrome w/ St John’s wort. May cause hypertensive crisis w/ tyramine-rich food and beverages. Increased sedative effects w/ alcohol.
Lab Interference
May cause false-positive reaction w/ urine detection of amphetamine/methamphetamine.
Action
Description: Selegiline increases dopaminergic activity by intervening w/ the reuptake of dopamine at the synapse. It also irreversibly inhibits monoamine oxidase (MAO)-B which is involved in the metabolism of dopamine in the brain. Onset: W/in 1 hr (oral). Duration: 24-72 hr (oral). Pharmacokinetics: Absorption: Readily absorbed from the GI tract. Bioavailability: Approx 10%. Time to peak plasma concentration: 30 min (oral conventional preparation). Distribution: Rapidly distributed throughout the body; crosses the blood-brain barrier. Plasma protein binding: Up to 94%. Metabolism: Undergoes extensive first-pass metabolism; converted to at least 5 metabolites including l-(-)-desmethylselegiline (norselegiline), l-(-)-N-methylamfetamine and l-(-)-amfetamine. Excretion: Mainly via urine, as metabolites; faeces (approx 15%). Elimination half-life: 10 hr (oral); 18-25 hr (transdermal).
Chemical Structure
Selegiline Source: National Center for Biotechnology Information. PubChem Database. Selegiline, CID=26757, https://pubchem.ncbi.nlm.nih.gov/compound/Selegiline (accessed on Jan. 23, 2020)
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