Generic Name

Selegiline

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Classification

FDA Approved Indications

• Major depressive disorder (particularly in treatment-resistant cases)
• Parkinson's disease (as adjunct therapy)

Mechanism of Action

Selegiline selectively inhibits monoamine oxidase B (MAO-B), leading to increased levels of dopaminergic and other monoamine neurotransmitters in the central nervous system, which helps alleviate depressive symptoms and provides neuroprotective effects in Parkinson's disease.

Dosage and Administration

Adult: Emsam transdermal patches starting at 6 mg/24 hr, may be increased to 9 mg/24 hr or 12 mg/24 hr based on response and tolerability.

Pediatric: Not approved for pediatric use.

Geriatric: Use with caution; start at lower doses and monitor closely due to increased sensitivity and potential drug interactions.

Renal Impairment: No specific dose adjustment required; however, caution advised.

Hepatic Impairment: Use with caution; monitor for increased adverse effects.

Pharmacokinetics

Absorption: Rapidly absorbed through skin when applied as a transdermal patch.

Distribution: Widely distributed in tissues, crosses blood-brain barrier.

Metabolism: Metabolized in the liver, primarily by deamination by CYP450 enzymes.

Excretion: Excreted mainly via renal pathways.

Half Life: Approximately 3 hours for plasma, but effects are prolonged due to sustained inhibition of MAO-B with transdermal application.

Contraindications

• Concurrent use of other MAO inhibitors or within 14 days of MAOI discontinuation.
• History of hypersensitivity to selegiline.

Precautions

• Use with caution in patients with hypertension, cardiovascular disease, or a history of stroke.
• Risk of hypertensive crisis if dietary tyramine is ingested while on therapy.
• Caution in patients with psychiatric conditions or on serotonergic agents due to risk of serotonin syndrome.

Adverse Reactions - Common

• Application site rash or irritation (Common)
• Insomnia (Common)
• Dizziness or headache (Common)

Adverse Reactions - Serious

• Hypertensive crisis, especially with high tyramine foods or certain medications (Rare but serious)
• Serotonin syndrome, when combined with other serotonergic drugs (Rare but serious)
• Orthostatic hypotension (Uncommon)

Drug-Drug Interactions

• Other antidepressants (especially SSRIs, SNRIs, TCAs), sympathomimetics, opioids, certain anesthetics.

Drug-Food Interactions

• High-tyramine foods (aged cheeses, cured meats, some wines) to avoid hypertensive crisis.

Drug-Herb Interactions

• St. John’s Wort, ginseng, and other serotonergic herbs may increase risk of serotonin syndrome.

Nursing Implications

Patient/Family Teaching

• Instruct on proper patch application and rotation.
• Advise to avoid tyramine-rich foods.
• Inform about potential side effects and when to seek medical help.
• Emphasize adherence to dosing schedule and regular follow-ups.

Special Considerations

Black Box Warnings:

• Hypertensive crisis due to dietary tyramine.

Genetic Factors: Genetic variations may affect metabolism and response, but specific testing is not routine.

Lab Test Interference: No significant interference reported.

Overdose Management

Signs/Symptoms: Severe hypertension, agitation, hyperthermia, seizures, or coma.

Treatment: Seek emergency medical attention. Manage hypertension with IV antihypertensives, stabilize vital signs, and provide supportive care.

Storage and Handling

Storage: Store at room temperature, away from moisture, heat, and light.

Stability: Stable for the duration of the prescribed therapy, check manufacturer’s recommendations.