Selegiline
An irreversible MAO-B inhibitor added to levodopa in Parkinson's disease; as a skin patch it treats major depression.
Also called L-deprenyl (older name).
Drug card
- Class
- MAO-B inhibitor
- How it works
- Blocking MAO-B, the brain enzyme that breaks down dopamine
- Used for
- Parkinson's disease, added to levodopa
- Major depression (skin patch)
- Known for
- Insomnia and vivid dreams
- Serotonin syndrome with pethidine, SSRIs or tricyclics
- Its name
- -giline means an MAO-B inhibitor
Study it as a flashcard, and it comes back before you forget it.
Mechanism of action
How does selegiline work?
A 'suicide' substrate: MAO-B turns selegiline into a reactive form that binds the enzyme for good, so less dopamine is broken down in the brain. It is selective for MAO-B only around the usual oral dose. Two of its main metabolites are amphetamine and methamphetamine, which act on neurotransmitter release themselves.
Like other MAO-B inhibitors: MAO-B inhibitors irreversibly block monoamine oxidase type B, the main form of the enzyme in the human brain, where it breaks down dopamine. With less breakdown, more dopamine stays in the striatum, easing Parkinson's symptoms and cutting 'off' time on levodopa. At licensed doses they spare MAO-A, which clears dietary tyramine in the gut, but this selectivity fades as the dose rises.
Uses
What is selegiline used for?
- Parkinson's disease, added to levodopa
- Major depression (skin patch)
Side effects
Side effects of selegiline
- Insomnia and vivid dreamsKnown for
- Serotonin syndrome with pethidine, SSRIs or tricyclicsKnown forSerious
- Nausea
- Dizziness, light-headedness or fainting
- Low blood pressure on standing
- More dyskinesia and other levodopa effects
- Hallucinations and confusionSerious
- Dry mouth
- Hypertensive reaction with tyramine or high dosesSerious
- Compulsive gambling, sexual or other urgesSerious
- Suicidal thoughts in young people (patch)Serious
- Melanoma (link to the drug unclear)Serious
Known for marks what an exam expects you to know it for.
Watch for
Cautions and what sets it apart
- Pethidine is contraindicated: with selegiline it can cause stupor, rigidity, agitation and fever, sometimes fatal.
- Tricyclics and SSRIs are avoided: leave 14 days after stopping selegiline, and 5 weeks after stopping fluoxetine.
- Oral selegiline stays MAO-B selective only at the licensed dose; higher doses risk the cheese reaction.
- The stronger patches need a tyramine-restricted diet, and the patch is contraindicated under 12 years.
Good to know: Unlike rasagiline it is metabolized to amphetamine and methamphetamine, and as a skin patch it is also licensed for major depression.
Remember it
A way to remember it
B for brain, A for abdomen.
MAO-B is the main form in the brain, where blocking it spares dopamine; MAO-A dominates in the gut, where it breaks down tyramine from food, so sparing it keeps the cheese reaction rare at licensed doses.
Written for biofideX
Its name
-giline means MAO-B inhibitor
Selegiline and rasagiline block MAO-B, the main form of the enzyme in the brain, slowing dopamine breakdown in Parkinson's disease. Phenelzine, an MAO inhibitor for depression, lacks it.
- Every drug name stem
Its class
MAO-B inhibitors
Other MAO-B inhibitors with a card:
Easily mixed up with monoamine oxidase inhibitors and dopamine agonists.
Sources
Checked against
Written for biofideX in plain words, after checking these references:
- Selegiline hydrochloride tablets: label (DailyMed)
- Selegiline transdermal system: label (DailyMed)
- Selegiline hydrochloride (NCI Thesaurus)
For learning pharmacology, not for treatment decisions: no doses are given, and a prescriber, pharmacist or the product's own label is the word on any one patient. Spotted a mistake? Tell us and we'll correct it.
Parkinson's, dementia and migraine
Selegiline is one of 9 drugs practiced together here: their classes, how they work, what they treat and what they're known for.
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