How medicine gets into your body is called a “delivery system.” It might be an injection, a pill, a drink or a piece of adhesive you stick to your skin. The latter is a “transdermal patch,” and it might be the preferred method to absorb medication if you have trouble swallowing pills, trouble remembering to take medicine on schedule or the medication is most effective if it’s absorbed slowly and regularly.
As simple as a patch is, it’s actually a sophisticated drug delivery system designed to release small quantities of the drug through the skin and into the bloodstream over a long period of time. Some patches are worn for weeks at a time.
Medications commonly delivered via patch include:
- pain relievers;
- nicotine (for people trying to quit smoking);
- drugs to prevent angina (chest pain caused by insufficient blood to the heart);
- drugs to treat motion sickness.
Scopolamine (Transderm Scōp), which treats motion sickness, was the first drug to be delivered transdermally. Users stick it behind their ears a few hours before taking the cruise or car trip or whatever is likely to give them nausea. It generally remains effective for three days.
The diclofenac (Flector) patch relieves minor pain when placed directly over a bruise or sprain (other patches are placed in specific places noted on the product’s directions). Some prescription patches-fentanyl (Duragesic)-deliver a strong narcotic, and are used only to treat chronic, severe pain.
The idea behind the nicotine patch is to wean smokers off their dependence slowly and reduce withdrawal symptoms. Nicotine patches (Habitrol, Nicoderm, Nicoderm CQ and Nicotrol as well as generics) are available in various strengths, and the idea is to decrease the strength as time goes by.
Hormone patches often are prescribed to relieve symptoms of menopause and prevent osteoporosis (bone loss), and low testosterone for men.
Nitroglycerin patches (Minitran, Nitro-Dur, Nitrodisc and Transderm-Nitro) address angina by relaxing the constricted blood vessels of coronary artery disease (CAD) to enable the heart to get more blood and oxygen. Nitroglycerin patches can prevent the pain of angina but do not treat chest pain.
The obvious benefits of transdermal patches, noted above, are accompanied, like all medicine, by potential risks and side effects. If your doctor prescribes or suggests a drug patch for you, ask:
- What are the expected side effects?
- What are the possible side effects?
- What other drugs should I avoid?
- What food or liquids should I avoid?
- Are there environmental effects (for example, should you avoid sun exposure)?
- For what side effects should I call you (for example, fever or rash)?
- How long will the drug be active after I remove the patch?
According to the Poison Control Center, take these precautions when using transdermal patches:
- Apply the patch firmly; it might take 20 or 30 seconds to get all of the adhesive stuck firmly in place.
- Wash your hands after applying a patch to yourself or someone else.
- Use only one patch at a time unless the instructions say otherwise.
- Patches might have to be removed if you need an MRI during the course of treatment; ask your doctor or X-ray technician.
- If you develop skin irritation from the adhesive, replace the next patch in another area. If the problem remains, call your doctor.
- When your remove a skin patch, fold it to stick the adhesive edges together. Dispose of it out of reach of children or pets.
- Gently wash the area with soap and water.
It is possible to overdose on medicine delivered via patch if it is broken or cut open and the medicine gets on and through another area of skin. Overdose is a risk as well if you wear too many patches.
Overdose can also happen if the user lets the area of the patch get hot, such as with an electric blanket.
Beware of the risk of overdose to children if:
- they find patches and put them in their mouths (the Poison Control Center reported one child who had several fentanyl patches stuck to the roof of her mouth);
- they get adult patches stuck to their skin after rolling in the parental bed where a patch has come unstuck from its original host.
If you suspect an overdose, remove the patch and wash the skin with soap and water. Then call the poison center immediately at (800) 222-1222. Its experts will tell you exactly what to do. If it’s necessary to seek hospital treatment, the poison center will call ahead to the emergency department to provide treatment recommendations.
Call the poison center even if the person seems OK-even after removing the patch, some drug remains in the body. The poison center will stay in touch with you to be sure that no problems develop.