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MAO-B Inhibitors

Selegiline (also called deprenyl, with trade names Eldepryl®and Zelapar®) and rasagiline (Azilect®) block an enzyme in the brain that breaks down levodopa.

Selegiline (also called deprenyl, with trade names Eldepryl®and Zelapar®) and rasagiline (Azilect®) block an enzyme in the brain that breaks down levodopa. These drugs have a modest effect in suppressing Parkinson’s symptoms. They have been shown to delay the need for Sinemet when prescribed in the earliest stage of PD and have been approved for use in later stages of PD to boost the effects of Sinemet. Eldepryl® may interact with anti-depressants, narcotic pain killers and decongestants. Check with a doctor before taking any new medications.

What are the Facts?

  • Enzymes naturally break down several chemicals in the brain, including dopamine A chemical messenger (neurotransmitter) that regulates movement and emotions..
  • Helps block the breakdown of dopamine in the brain. This makes more dopamine available and reduces some of the motor symptoms of PD.
  • Provide modest benefit for the motor features of PD. 
  • Usually used early in the disease as monotherapy (meaning it is the only drug taken) or as an adjunct (add-on) to other medications.
  • When used together with other medications, MAO-B inhibitors may reduce “off” time and extend “on” time.

The MAO-B inhibitors selegiline and rasagaline enhance the effect of levodopa:

Selegiline is available in two formulations:

  • Standard oral (Eldepryl®) – This form gets converted by the body into an amphetamine-like by-product, which may contribute to side effects of jitteriness and confusion. Alternatively, this side effect may be helpful to treat excessive daytime fatigue.
  • Orally-disintegrating (Zelpar®) – This is the preferred form for people with PD who have difficulty swallowing.

Rasagiline is available in 0.5 mg and 1 mg doses:

  • Rasagiline (Azilect®) is generally given in one mg doses once per day. Two studies (LARGO and TEMPO) have shown that it can reduce wearing off in people treated with levodopa.
  • It is structurally different than selegiline and does not have the amphetamine-like byproduct that can cause jitteriness. 
  • Recently, the FDA expanded the indication for rasagiline from monotherapy and adjunct to levodopa to include adjunct to dopamine agonists. This means that rasagiline can be used alone or in combination with other PD medications. However, there may be contraindications with other prescription medications, vitamins, over-the-counter cold pills or homeopathic remedies. Talk to your doctor and pharmacist about potential drug interactions.

Recent studies have led to the reclassification of these medications as highly selective MAO-B inhibitors.  

What are the side effects?

The most common side effects of MAO-B inhibitors include:

  • Mild nausea
  • Dry mouth
  • Lightheadedness
  • Constipation
  • Confusion (can occur in elderly people with PD)
  • Hallucinations (can occur in elderly people with PD)

Taking some MAO-B inhibitors with the heavy consumption of aged cheeses or wines high in tyramine carries a risk of raising blood pressure to dangerous levels, but this "cheese effect" has not been found in selegiline and rasagiline. The FDA has relaxed food restrictions related to MAO-B inhibitors. 

Caution: PD medications may have interactions with certain foods, other medications, vitamins, herbal supplements, over-the-counter cold pills and other remedies. Anyone taking a PD medication should talk to his or her doctor and pharmacist about potential drug interactions.


Available Doses

Initial Dosing

Side Effects*




(Eldepryl®, Carbex®)

5 mg

5 mg 2X/day

(max dose)

Agitation, insomnia, hallucinations

Tertiary medication; controls brain’s metabolism of dopamine

Anti-depressants, narcotic painkillers, decongestants

Selegiline HCI
Orally disintegrating tablet


1.25mg 1X daily

Dizziness, nausea, pain, headache, insomnia, rhinitis, dyskinesias, back pain, stomatitis, dyspepsia

Adjunct to levodopa in patients with significant "off" periods

Anti-depressants, narcotic painkillers, decongestants

Rasagiline (Azilect®)


0.5mg 1X daily

Increased dyskinesias, postural hypotension, headaches, joint pain, indigestion

Signs and symptoms of PD as initial monotherapy and adjunct to levodopa

Narcotic painkillers, anti-depressants and decongestants. Diets or meals very high in tyramine-rich foods (i.e. draft beer, red wine, aged cheeses, and similar) are not recommended (diets or meals with moderate amounts of these foods are not a problem).

* Please note that the side effects listed in the tables that accompany each class of medication are the most commonly experienced. Not all individuals will experience such side effects. For many people who do experience side effects, they can often be effectively limited or eliminated with careful adjustments to dosage or the timing of the individual doses.

Speak to the treating physician immediately if any side effects are experienced. For a complete description of each drug and its possible side effects, please request a “package insert” from your pharmacist for each drug used. It is recommended that all prescriptions be filled at the same pharmacy to avoid interactions between medications. Interactions can be dangerous and even life-threatening, so make sure the pharmacist knows of all medications and supplements being taken, including over-the-counter medications and supplements.

Page reviewed by Dr. Chauncey Spears, Movement Disorders Fellow at the University of Florida, a Parkinson’s Foundation Center of Excellence.

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