Skin Patches Increasingly Replace Pills

Over the past few decades, the FDA has approved an alternative to the traditional method of daily pill-popping. Medications can now be taken through relatively effortless skin patches, a quick and easy way release medication into the bloodstream.

In May, the FDA announced the approval of Neupro, the first skin patch designed to treat symptoms of early Parkinson's disease. Last February, there was the approval of Emsam, the first skin patch used to treat depression.

A benefit of patches is that they offer increased convenience to administer drugs which would otherwise require frequent dosing. In addition there is improved patient compliance and comfort because of the non-invasive, painless and simple application. Common side effects are possibility of local irritation, itching or swelling at the application site.

There also has been concern about this method of introducing drugs into the body. In 2005 the FDA began investigating reports of death and other serious side effects from overdoses of fentanyl in patients using skin patches containing this drug for pain control. The FDA also approved updated labeling more than once for the Ortho Evra contraceptive patch. Last year, the FDA updated labeling information on Ortho Evra to warn patients of the risk of blood clots as a result of using the medication.

In 2005, healthcare providers and patients were warned that this product exposes women to higher levels of estrogen than most birth control pills. The change specifically states that women who use Ortho Evra are exposed to about 60 percent more total estrogen in their blood than if they were taking a typical birth control pill.

Transdermal, or skin patches were developed in the 1970s, and the first one was approved by the FDA in 1979 for the treatment of motion sickness. In the mid-1980s, pharmaceutical companies started the development of a nicotine patch to help smokers quit smoking, and by 1992 the FDA had approved four nicotine patches.

They now are used for many reasons, including birth control, hormone replacement, insulin, pain relief, depression and most recently Parkinson's Disease.

In Parkinson's disease, dopamine-producing brain cells falter and die. Neupro patches deliver a new drug called rotigotine through the skin. Rotigotine is a member of a class of drugs called dopamine agonists, which mimic dopamine's effects.

Some doctors are advocates of transdermal patches, because they feel patients will be more willing to take their medication. Dr. Chester Hudson, of Chicago IL., commented on how doctors have a lot of problems with "patient compliance" when it comes to getting them to faithfully take their prescriptions. He said that the patch is a convenient solution.

"Its not that these are different medications, it's just a different delivery system," he said. "The reason they made that kind of delivery system is because people don't like taking meds." He said the side effects that skin patches may cause are no different than the ones they would get taking the same medication in a different form, such as pills.

One problem that concerns some people and medical professionals when it comes to the patch is possible leaks, which would cause medicines that are supposed to be time released to enter the body too quickly or at levels that are too high. This was the case with the fentanyl patch.

The typical patch is constructed with a liner, which protects the patch during storage and is removed prior to use, the drug solution that is in direct contact with the release liner, the adhesive, which holds the components of the patch together along with allowing the patch to stick to the skin, the membrane, which controls the release of the drug from certain types of patches and the backing, which protects the patch from the outer environment.

There are four main types of transderrmal patches. There is the single-layer drug-in-adhesive patch. The adhesive of this patch not only holds the components together and allows the patch to stick to the skin, it is also responsible for the releasing of the drug. The adhesive layer is surrounded by a temporary liner and a backing.

The multi-layer drug-in adhesive patch is similar to the single-layer patch in that both adhesive layers are also responsible for the releasing of the drug. The multi-layer system is different however that it adds another layer of drug-in-adhesive, usually separated by a membrane.

Unlike the previously mentioned two patches, the reservoir transdermal patch has a separate drug layer. The drug layer is a liquid compartment containing a drug solution or suspension separated by the adhesive layer. This patch is also backed by the backing layer. The matrix patch has a drug layer of a semisolid matrix, or substance, containing a drug solution or suspension. The adhesive layer in this patch surrounds the drug layer partially overlaying it.

The U.S. Food and Drug administration recognizes 111 distinct routes of administration, or paths by which a drug, fluid, poison or other substance is brought into contact with the body. The Center for Drug Evaluation and Research lists them all in its Data-Standards Manual, which provides for all routes of administration for drugs.

According to FDA Patient Safety News, a video news show produced for health professionals by the administration, a common problem with this method occurs when the old patch is not removed when the new patch is applied. That's particularly a problem with clear patches, because they can be difficult to find when it's time to remove or replace them. The risk of error increases when there are multiple caregivers. According to a show aired in 2003 regarding the use of this type of delivery system, "Although transdermal patches provide a useful alternative to oral medications, using them can lead to medication errors, resulting in patient harm and even death."

The bottom line seems to be ensuring that a patient uses the patch correctly to ensure that the medication is able to be released correctly into the body. Also, external factors such as heat may play a role in how the drug is absorbed. An FDA public heath advisory about the fentanyl patch stated that "absorption of the drug can also be increased by exposing the patch to heat sources such as heating pads, electric blankets or long, hot baths. "

The administration advises that people are instructed on how to safely use, store and dispose of the patches. Doctors and the FDA continue to back their safety, but as with all medications, patients must consider the risks before deciding if this method of delivery is right for them.