Karen L. Swartz, M.D., assistant Professor of Psychiatry at Johns Hopkins, explains why the transdermal Emsam patch offers new hope for patients with depression.
In 2006 the Food and Drug Administration (FDA) approved Emsam (selegiline), the first skin (transdermal) patch for use in treating major depression. The once-a-day depression patch works by delivering selegiline, a monoamine oxidase (MAO) inhibitor, through the skin and directly into the bloodstream, without having to pass through the digestive tract first.
At its lowest strength, Emsam can be used without the dietary restrictions required for all oral MAO inhibitors, making it a far more attractive drug option for people whose depression responds best to MAO inhibitors.
MAO inhibitors, such as Nardil (phenelzine) and Parnate (tranylcypromine), increase brain levels of norepinephrine, serotonin, and dopamine by blocking the action of the enzyme MAO, which normally inactivates these three neurotransmitters. They are effective in many people with depression , especially those whose depression is accompanied by marked anxiety, panic attacks, heightened appetite, or excessive sleeping.
But, as a drug class, MAO inhibitors are typically a last choice for people with depression because of their safety risks. In the intestines, the enzyme MAO breaks down tyramine, a substance found in certain foods and beverages. Oral MAO inhibitors block the breakdown of tyramine in the intestine. This is dangerous because, if a large amount of tyramine is absorbed from the intestine, it can lead to a sudden and extreme elevation in blood pressure called “hypertensive crisis,” which is potentially life threatening and requires immediate medical treatment. Foods high in tyramine include aged cheese, aged or smoked meats, tap beer, and very ripe bananas. Nasal decongestants and cold and allergy medicines also contain tyramine.
Emsam represents a significant advance because the innovative transdermal delivery system allows the MAO inhibitor to bypass the digestive tract. At the lowest dose of the patch, which delivers 6 mg of selegiline over a 24-hour period, no dietary restrictions are necessary.
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