Selegiline (Eldepryl)

Primer

Selegiline (Tradename: Eldepryl) is a monoamine oxidase inhibitor (MAOI) used in the treatment of Parkinson's disease and depression.

Pharmacokinetics

See also article: Introduction to Pharmacology

Pharmacokinetics of Selegiline

Absorption
Distribution
Metabolism
Elimination
Half-life

Cytochrome P450 Metabolism

See also article: Cytochrome (CYP) P450 Metabolism

Selegiline: Cytochrome P450 Metabolism

Substrate of (Metabolized by)
Induces
Inhibits

Pharmacodynamics

Mnemonic

At the right doses, SELEgiline SELEctively inhibits MOA-B (B for Brain)

Selegiline is a centrally acting irreversible monoamine oxidase type B (MAO-B) inhibitor.
- This increases dopamine availability (and hence why it is also used in Parkinson's)
It has greater affinity for MAO type B than MAO type A, and thus serves as a selective inhibitor of MAO-B when administered at the recommended dose.
- At larger doses, it loses its specificity and also inhibits MAO-A.
Two active metabolites of selegiline are l-amphetamine and l-methamphetamine, which interfere with neuronal re-uptake and enhance the release of several neurotransmitters (e.g. - norepinephrine, dopamine, serotonin). The extent to which these neurotransmitters contribute to selegiline’s effects are unknown.^[1]
In patients with advanced Parkinson’s Disease, selegiline increases dopamine levels reducing the breakdown of dopamine generated from levodopa. Thus, selegiline improves the therapeutic effect of levodopa.

Toxicity

Indications

Parkinson's Disease, in newly diagnosed patients, selegiline was shown to delay the need to implement levodopa therapy.

Dosing

Dosing for Selegiline

Starting
Titration
Maximum
Taper

Formulations

Selegiline comes in oral formulation

Monitoring

Dietary Restriction

Selegiline can only be used safely without dietary restrictions at doses where it selectively inhibits MAO-B (e.g. - 10 mg/day).^[2]

Contraindications

Absolute

Extrapyramidal symptoms such as excessive tremor or tardive dyskinesia, or in patients with severe psychosis or severe dementia
Do not combine with selective serotonin reuptake inhibitors and tricyclic antidepressants (risk of serotonin syndrome)
Meperidine and opioids
Active peptic ulcer

Relative

Drug-Drug Interactions

Side Effects

Adverse Events

Clinical Pearls

Selegiline is thought to have no to little sexual side effects.^[3]

Special Populations

Geriatric

See main article: Geriatric Pharmacology

Pediatric

See main article: Pediatric Pharmacology

Obstetric and Fetal

See main article: Obstetric and Fetal Pharmacology

Medically Ill

See main article: Psychotropic Dosing in the Medically Ill

Resources

¹⁾ Health Canada. PRODUCT MONOGRAPH PrAPO-SELEGILINE Selegiline Hydrochloride Tablets USP

²⁾ Health Canada. PRODUCT MONOGRAPH PrAPO-SELEGILINE Selegiline Hydrochloride Tablets USP

³⁾ Clayton, A. H., Campbell, B. J., Favit, A., Yang, Y., Moonsammy, G., Piontek, C. M., & Amsterdam, J. D. (2007). Symptoms of sexual dysfunction in patients treated for major depressive disorder: a meta-analysis comparing selegiline transdermal system and placebo using a patient-rated scale. The Journal of clinical psychiatry, 68(12), 1860-1866.

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