What is an MAO Inhibitor?

Overview

MAO (monoamine oxidase) inhibitors are a class of drug used to treat depression. They include Nardil (phenelzine) and Parnate (tranylcypromine). A newer MAO inhibitor, Eldepryl (selegiline) is also used to treat Parkinson's Disease.

Function

MAO inhibitors block the action of the monoamine oxidase, the enzyme responsible for breaking down neurotransmitters in the central nervous system.

Significance

MAO inhibitors decrease depression by increasing levels of the neurotransmitters serotonin and norepinephrine in the central nervous system.

Types

Selegiline increases the amount of the neurotransmitter dopamine in the central nervous system. This reduces the movement disorders of Parkinson's Disease.

Warning

People taking MAO inhibitors may experience a dangerous and sometimes fatal spike in blood pressure if they eat foods containing the amino acid tyramine, such as pickled herring and aged wine and cheeses. Selegiline is less likely to cause this reaction, but it can occur with higher doses.

Drug Interactions

MAO inhibitors can seriously interact with pain medications, cold and cough medications and other antidepressants.

Considerations

MAO inhibitors are an effective treatment for depression, but they are not often used due to their potential for serious drug and food interactions. Patients taking MAO inhibitors should ask their doctor for a full list of foods and medications to avoid.