Parnate (Tranylcypromine) GlaxoSmithKline
Discovered in the 1950s, MAO inhibitors work by correcting chemical imbalances in the brain. Normally, natural chemicals called neurotransmitters carry signals from one brain cell to another. Some neurotransmitters, such as serotonin and norepinephrine, play important roles in controlling mood. But other substances in the brain may interfere with mood control by breaking down these neurotransmitters. Researchers believe that MAO inhibitors work by blocking the chemicals that break down serotonin and norepinephrine. This gives the neurotransmitters more time to do their important work. Because MAO inhibitors also affect other chemicals throughout the body, these drugs may produce many unwanted side effects. They can be especially dangerous when taken with certain foods, beverages and medicines. Anyone taking these drugs should ask his or her physician or pharmacist for a list of products to avoid. MAO inhibitors are available only with a physician's prescription. They are sold in tablet form. Some commonly used MAO inhibitors are isocarboxazid (Marplan), phenelzine (Nardil), and tranylcypromine (Parnate).