SELEGILINE HYDROCHLORIDE (L-DEPRENYL)

SELEGILINE HYDROCHLORIDE (L-DEPRENYL)
(se-leg'i-leen)
Carbex, Eldepryl, Emsam, Zelapar
Classifications: anticholinergic; antiparkinson agent;
Therapeutic: antiparkinson agent; antidepressant (maoi)
Prototype: Levodopa (L-dopa)
Pregnancy Category: C

Availability

5 mg tablets, capsules; 1.25 mg orally disintegrating tab; 6 mg, 9 mg, 12 mg transdermal patch

Action

Increase in dopaminergic activity is thought to be primarily due to selective inhibition of MAO type B activity. Ability of selegiline to control parkinsonism is thought to be due to increased dopaminergic activity. It interferes with dopamine reuptake at the synapse of neurons as well as its inhibition of MAO type B dopaminergic activity in the brain. Interference with dopamine reuptake at the MAO type A dopaminergic receptors in the brain is thought to be the mechanism for antidepression.

Therapeutic Effect

Effectiveness is measured in decreased tremors, reduced akinesia, improved speech and motor abilities as well as improved walking. At slightly higher doses it is an effective antidepressant.

Uses

Adjunctive therapy of Parkinson's disease for patients being treated with levodopa and carbidopa who exhibit deterioration in the quality of their response to therapy, major depressive disorder.

Unlabeled Uses

Attention deficit/hyperactivity disorder, extrapyramidal symptoms.

Contraindications

Hypersensitivity to selegiline; uncontrolled hypertension; concomitant use with meperidine and other opioids; suidical ideation; pregnancy (category C); lactation.

Cautious Use

Hypertension; history of suicide, bipolar disorder; psychosis. Safety and efficacy in adolescents and children are not established.

Route & Dosage

Parkinson's Disease
Adult: PO 5 mg b.i.d. with breakfast and lunch (doses >10 mg/d are associated with increased risk of toxicity due to MAO inhibition) PO (Zelapar) 1.25 mg q.d. x 6 weeks (max: 2.5 mg q.d.)
Geriatric: PO Start with 5 mg qa.m.

Depression
Adult: Transdermal 6 mg/d, may increase by 3 mg/d q2wk up to 12 mg/d

Administration

Oral

Do not give daily doses exceeding 10 mg/d.
Note: Concurrent levodopa and carbidopa doses are usually reduced 10–30% after 2–3 d of selegiline therapy.
Do not use concurrently with opioids (especially meperidine).
Store at 15°–30° C (59°–86° F).

Transdermal

Do not cut or trim patch.
Before application wash the area with soap and warm water. Dry thoroughly.
Apply to upper torso, upper thigh, or outer surface of upper arm. Do not apply to hairy, oily, irritated, broken, or calloused skin.
Rotate sites.
Wash hands after application.

Adverse Effects (≥1%)

CNS: Sleep disturbances, psychosis, agitation, confusion, dyskinesia, dizziness, hallucinations, dystonia, akathisia. CV: Hypotension. GI: Anorexia, nausea, vomiting, abdominal pain, constipation, diarrhea.

Interactions

Drug: tricyclic antidepressants may cause hyperpyrexia, seizures; fluoxetine, sertraline, paroxetine may cause hyperthermia, diaphoresis, tremors, seizures, delirium; sympathomimetic agents (e.g., amphetamine, phenylephrine, phenylpropanolamine), guanethidine, and reserpine may cause hypertensive crisis; cns depressants have additive CNS depressive effects; opiate analgesics (especially meperidine) may cause hypertensive crisis and circulatory collapse; buspirone, hypertension; general anesthetics—prolonged hypotensive and CNS depressant effects; hypertension, headache, hyperexcitability reported with dopamine, methyldopa, levodopa, tryptophan; metrizamide may increase risk of seizures; hypotensive agents and diuretics have additive hypotensive effects. Food: Aged meats or aged cheeses, protein extracts, sour cream, alcohol, anchovies, liver, sausages, overripe figs, bananas, avocados, chocolate, soy sauce, bean curd, natural yogurt, fava beans—tyramine-containing foods—may precipitate hypertensive crisis (less frequent with usual doses of selegiline than with other maois). Herbal: Ginseng, ephedra, ma huang, St. John's wort may cause hypertensive crisis.

Pharmacokinetics

Absorption: Rapid; 73% reaches systemic circulation. Onset: 1 h. Duration: 1–3 d. Distribution: Crosses placenta; not known if distributed into breast milk. Metabolism: In liver to N-desmethyldeprenyl-amphetamine and methamphetamine. Elimination: In urine. Half-Life: 15 min (metabolites 2–20 h).

Nursing Implications

Assessment & Drug Effects

Monitor vital signs, particularly during period of dosage adjustment. Report alterations in BP or pulse. Indications for discontinuation of the drug include orthostatic hypotension, hypertension, and arrhythmias.
Monitor for changes in behavior that may indicate increase suicidality, especially in adolescents or children being treated for depression.
Monitor all patients closely for behavior changes (e.g., hallucinations, confusion, depression, delusions).

Patient & Family Education

Do not exceed the prescribed drug dose.
Report symptoms of MAO inhibitor-induced hypertension (e.g., severe headache, palpitations, neck stiffness, nausea, vomiting) immediately to physician.
Do not drive or engage in potentially hazardous activities until response to drug is known.
Make positional changes slowly and in stages. Orthostatic hypotension is possible as well as dizziness, light-headedness, and fainting.
If the transdermal patch falls off, apply a new patch to a new area, and resume previous schedule.
Only one should be worn at a given time. Remove the old transdermal patch.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

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