The once-a-day patch, called Emsam, works by delivering selegiline, a monoamine oxidase inhibitor or MAOI, through the skin and into the bloodstream.
Selegiline isn't a new drug. It was initially approved in capsule form for use in Parkinson's disease.
Like other MAOIs, selegiline has carried warnings about possible dangerous interactions with certain foods and drinks, including aged cheeses and tap beer. The new patch's lowest dose may avoid some of those interactions.
"At its lowest strength, Emsam can be used without the dietary restrictions that are needed for all oral MAO inhibitors that are approved for treating major depression," states an FDA news release.
However, higher doses of the patch require dietary restrictions, and all of the doses carry other cautions.
The FDA's Steven Galson, MD, MPH, commented on the new patch, in a news release.
"Emsam provides a significant advance because at least in its lowest dose patients can use the drug without the usual dietary restrictions associated with these types of drugs known as MAO inhibitors," says Galson, who directs the FDA's Center for Drug Evaluation and Research.
Major depression is common in the U.S. Depression can often be treated by methods including counseling and antidepressants, which come in several forms including MAOIs. Depression symptoms can include sadness, fatigue, insomnia, changes in weight or appetite, loss of interest in usual activities, restlessness, suicide attempts, and suicidal thinking.
How MAOIs Work
MAOIs usually require specific dietary restrictions because when combined with certain foods they can cause a sudden, large increase in blood pressure. That problem, called "hypertensive crisis," can lead to a stroke and death.
Here's how hypertensive crisis can happen.
MAOIs block an enzyme called monoamine oxidase (MAO). Blocking MAO in the brain is thought to have antidepressant effects by preventing the breakdown of certain brain chemicals. But the body also uses MAO to break down a protein called tyramine, which we get from consuming aged cheeses, tap beer, and other foods and drinks.
If tyramine isn't broken down, the body may absorb too much of it. The result can be a hypertensive crisis -- in other words, a dangerous spike in blood pressure.
Symptoms of Hypertensive Crisis
"Patients who have these symptoms should get medical care right away," states the FDA.
The lowest dose of the MAOI patch, which delivers 6 milligrams of the medication over a 24-hour period, can be used without such dietary restrictions.
About the New Patch
The Emsam patch will be made available in three sizes that deliver 6 milligrams, 9 milligram, or 12 milligrams of selegiline per 24 hours. The patch sandwiches the drug between two lining layers.
Emsam has been shown to be safe and effective for treatment of major depressive disorder in two six- to eight-week studies and also in a longer-term study of patients, states the FDA.
The data for the lowest dose of Emsam support the recommendation that a modified diet is not required at this dose. Patients are advised to change the patch once a day.
The more-limited data available for Emsam 9-milligram/24-hour and 12-milligram/24-hour don't rule out food effects. Patients receiving those higher doses should follow dietary restrictions that advise them to avoid certain foods or beverages, such as aged cheese and wine.
The only common side effect of Emsam detected in placebo-controlled trials was a mild skin reaction where the patch is placed. There may be mild redness at the site when a patch is removed.
If the redness does not go away within several hours after removing the patch or if irritation or itching continues, patients are advised to contact their doctor.
A less common side effect was light-headedness related to a drop in blood pressure.
Avoid Direct Heat
Although the effects of heat on the patch are not known, the drug labeling advises doctors and patients about the possible effects of direct heat applied to the Emsam patch.
Direct heat may result in an increased amount of the drug absorbed from the patch. Patients should avoid exposing the patch to heating pads, electric blankets, heat lamps, saunas, hot tubs, or prolonged sunlight.
Like all approved antidepressants, this product carries a warning of increased suicidality in children and adolescents.
Emsam was developed by Somerset Pharmaceuticals, Inc. In December 2004, Bristol-Myers Squibb and Somerset entered into an agreement that provides Bristol-Myers Squibb with distribution rights to market Emsam after approval in the U.S.
Bristol-Myers Squibb and Somerset Pharmaceuticals have planned an educational campaign for patients and prescribers to ensure that advice on dietary modifications for the higher patch strengths is adhered to.
The companies plan to conduct both patient and health care provider surveys to assess the effectiveness of the educational campaign. They will also closely track reports of adverse events, and follow up on those that might represent hypertensive crises, to further ensure the patch's safe use.
In a news release, the drug companies list other cautions with Emsam, including interactions with various prescription drugs, as well as alcohol. The patch should be used in pregnancy only if the potential benefit justifies the potential risk to the fetus, the companies state.