MAO-B Inhibitors

MAO-B inhibitors slow the breakdown of dopamine in the brain. There are two MAO-B inhibitors, in three formulations, approved for use in PD in the United States.

Rasagiline (Azilect®)

Rasagiline in an oral tablet is approved for the treatment of signs and symptoms of Parkinson's disease as initial monotherapy and as adjunct therapy to levodopa.

Selegiline swallowed tablets (Eldepryl®, generics)

Selegiline in tablet form is approved as an adjunct in the management of parkinsonian patients being treated with levodopa/carbidopa who exhibit deterioration in the quality of their response to this therapy.

Selegiline orally dissolving tablet (Zelapar®)

An orally dissolving form of selegiline is available for patients who have difficulty swallowing, or prefer not to take pills. It is approved as an adjunct in the management of patients with Parkinson's disease being treated with levodopa/carbidopa who exhibit deterioration in the quality of their response to this therapy.

Side effects of MAO-B inhibitor therapy include insomnia, hallucinations, and orthostatic hypotension. Patients who are also taking certain types of antidepressants may not be eligible to take MAO-B inhibitors, since these drugs may interact to dangerously raise blood pressure (called the serotonin syndrome). Patients are also cautioned to avoid certain types of foods that are high in tyramine, a dietary amino acid. These foods include certain kinds of aged cheeses, fermented meats, and fermented soy products. More information on this is available HERE (http://www.mdvu.org/emove/article.asp?ID=888).

Selegiline

Selegiline offers mild symptomatic benefit, primarily for patients with early disease. The dose is 5 mg twice each day. Side effects include insomnia, hallucinations, and orthostatic hypotension. Patients who are also taking certain types of antidepressants may not be eligible to take selegiline, since these drugs may interact to dangerously raise blood pressure (called the serotonin syndrome).

MAO-B inhibitors and neuroprotection

Neuroprotection refers to the ability to prevent or slow the death of neurons. Selegiline was the subject of a major neuroprotective trial in PD, the DATATOP trial. While the initial analysis of the results appeared to indicate that selegiline slowed disease, more detailed study indicated that the benefit seen could also be explained by its symptomatic effects. Thus, the results of this trial were inconclusive.

In 2004, a preliminary trial of rasagiline with a different trial design suggested that rasagiline may have disease-modifying properties. This study will need to be repeated and expanded before firm conclusions can be drawn.

	Anticholinergics