Selegiline

Antiparkinsonian Drug

Drug class: Monoamine Oxidase B Inhibitor, MAO-B Inhibitor

Selegiline（中文：司來吉蘭）

Common Strengths of Selegiline

• Oral Tablets: 5 mg

Drug Trade Names

• Eldepryl

Drug Usage

• Parkinson's Disease: Used to manage symptoms, often in conjunction with levodopa.
• Major Depressive Disorder: Available as a transdermal patch (Emsam) specifically for this indication.

Mechanism of Action

Selegiline selectively inhibits monoamine oxidase type B (MAO-B), which prevents the breakdonw of dopamine in the brain, thereby increasing its levels. At higher doses, it also inhibits monoamine oxidase type A (MAO-A), affecting serotonin and norepinephrine levels.

Route of Administration

• Oral (Tablet)
• Transdermal patch

Dosages

• Oral: 5 mg twice daily (maximum 10 mg/day).

Side Effects

Frequency	Adverse reactions
Common Side Effects	Dizziness
	Nausea
	Insomnia
	Skin rash
Serious Side Effects	Hypertensive crisis
	Serotonin syndrome
	Uncontrollable urges (gambling, eating)

Pharmacokinetics

• Onset of Action: Typically within hours
• Duration: Effects can last up to 24 hours depending on the formulation.

Drug Precautions

Pregnancy

Use with caution; benefits must outweigh risks.

Breastfeeding

Safety is unclear; use caution if breastfeeding.

Drug Monitoring Items

• Blood Pressure Monitoring: Patients should regularly monitor their blood pressure to manage the risk of orthostatic hypotension and prevernt hypertensive crises.
• Parkinsonism Symptoms: Patients should be monitored for worsening Parkinsonian symptoms, which may indicate inadequate control of the disease or adverse effects from the medication.
• Serotonin Syndrome: Symptoms such as agitation, confusion, and muscle spasms should be closely observed, especially if selegiline is combined with other serotonergic medications.
• Behavioral Changes: Regular assessments for mood changes and suicidal thoughts are necessary.

Drug Interactions

Selegiline has significant interactions with:

• Serotonergic Agents
  • SSRIs and SNRIs: Comgining selegiline with selective serotonin reuptake inhibitors (e.g. fluoxetine, sertraline) or serotonin-norepinephrine reuptake inhibitors (e.g. venlafaxine) can lead to serotonin syndrome, a potentially life-threatening condition characterized by symptoms such as agitation, confusion, rapid heart rate, and muscle rigidity.
• Opioids
  • Meperidine and Tramadol: The use of selegiline with opioids like meperidine or tramadol is contraindicated due to the risk of severe side effects, including respiratory depression and serotonin syndrome.
• Indirect Sympathominetics
  • Amphetamines and Ephedrine: These can cause hypertensive Crises when taken with selegiline due to increased norepinephrine levels. Monitoring blood pressure is essential when these combinations are necessary.
• Dextromethorphan
  • This common cough suppressant can also lead to serotonin syndrome when used concurrently with selegiline.
• Antidepressants
  • tricyclic antidepressants (e.g. amitriptyline) can interact with selegiline, necessitating caution and possibly dose adjustments.
• Benzodiazepines
  • The combination may enhance CNS depression effects, requiring careful monitoring and possible dose adjustments.
• Food and Alcohol Interactions
  • Tyramine-Rich Foods: Patients taking selegiline should avoid foods high in tyramine (e.g. aged cheeses, and cured meats) to prevent hypertensive crises.
  • Alcohol: Using alcohol while on selegiline may exacerbate side effects such as dizziness and drowsiness.

FAQ

How Should I Take the Tablet?

Take orally as prescribed.

What Should I Avoid While Taking?

Avoid tyramine-rich foods (e.g. aged cheeses and cured meats) and certain medications that can interact dangerously with selegiline, as listed in section " Drug Interactions".

What Happens if I Miss a Dose?

Take it as soon as youy remember unless it is almost time for your next dose. Do not double doses.