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Using Skin Patch Medicines
(Transdermal Patches)
Many people benefit from
drugs that are absorbed slowly and regularly. Some find it difficult
to swallow pills. Remembering to take a drug frequently is hard for
others.
Fortunately, some drugs
can be taken by putting on a skin patch. Using these “transdermal”
drugs is simple. But this type of patch is actually a sophisticated
drug delivery system. It is designed to release small quantities of
drug into the blood stream over a long period of time. Drug is
absorbed from the patch, through the outer layers of skin, and into
deeper layers. There, it is absorbed into the blood stream and
circulated through the body.
These “skin patch” drugs
include pain relievers, nicotine, hormones, and drugs to treat
angina and motion sickness. There are several advantages to taking drugs via patches:
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They are absorbed at a
fairly steady rate.
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You don’t have to
remember to swallow frequent doses.
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You can take them even
if you have an upset stomach, as you might with motion
sickness.
Scopolamine, a motion
sickness drug, was the first to be used in a skin patch. Victims of
motion sickness place a patch behind the ear, ideally a few hours
before symptoms are likely to start. The same patch can remain in
place for up to three days. A brand name is
Transderm Scōp®. 
Nicotine
patches are used to help people stop smoking. They provide a slow,
steady amount of nicotine to the blood stream. This takes the place
of nicotine from inhaling cigarette smoke and helps prevent
withdrawal symptoms. Several strengths are available. People can
gradually decrease the nicotine dose they receive from patches. The
goal is to stop using nicotine altogether. Some people who are
trying to stop smoking find the steady amount of nicotine from
patches a better treatment than intermittent nicotine use with gum
or lozenges. Nicotine patches are available without a prescription.
Some brand names are Habitrol®, Nicoderm®, Nicoderm CQ®, and
Nicotrol®. Nicotine patches also are available in generic form.
Diclofenac
in a patch is used to relieve minor pain. Examples are sprained
ankles and bad bruises. Unlike other patches, diclofenac patches are
put on the skin just over the area that hurts. Continuing pain
relief can make it easier to carry out normal activities. The brand
name for diclofenac patches is Flector®.
Nitroglycerin patches are used by people who have angina. This is
chest pain caused by narrow blood vessels in the heart (coronary
artery disease.) Nitroglycerin relaxes those blood vessels so the
heart gets more blood and more oxygen. Nitroglycerin patches can
prevent angina pain but they are not used to treat chest pain. These patches
usually are worn for 12 – 14 hours a day and then removed until the
next day. Some brand names are Minitran®, Nitro-Dur®, Nitrodisc®,
and Transderm-Nitro®.
Fentanyl
patches contain a strong narcotic. They are used only to treat
chronic, severe pain. Several dosage strengths are available;
patches need to be replaced only every three days. Duragesic® is a
brand name.
The active
ingredient in transdermal patches has the same benefits as those
drugs in other forms. Likewise, they carry the same potential side
effects and risks. Before taking any drug in a patch, ask your
doctor about:
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Expected effects.
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Possible side effects.
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Possible drug interactions.
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Drugs
or foods to avoid.
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Environmental factors to avoid, for example, staying out of the
sun.
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When
you should call for an urgent appointment. For example, could a
fever put you at risk for problems with this drug?
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How
long will the drug be active after you remove a patch?
There are
special precautions when using transdermal patches.
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Apply
the patch to clean, dry, unbroken skin. If the skin is broken or
irritated, too much drug could be absorbed.
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Be
sure the patch is applied firmly. It may take 20 or 30 seconds
to get all of the adhesive to stick firmly in place.
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Wash
your hands after applying a patch to yourself or someone else.
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Use
only one patch at a time unless the instructions say otherwise.
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If you
need an MRI, the patch may need to be removed during your test.
Check with your doctor or x-ray technician.
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If you
develop skin irritation from the adhesive, put the next patch in
another area. Check with your doctor about what to do next.
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When
your remove a skin patch, fold it so the adhesive edges stick
together. Throw it away so that children or pets cannot get to
it.
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Gently
wash the area with soap and water.
People who
use transdermal patches can suffer an overdose if the patch is
broken or cut open; too much medicine gets on and through the skin.
Wearing too many patches can cause an overdose, too.
Children
have been poisoned by skin patches in a number of ways:
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Taking
skin patches from the trash and sucking on them. One youngster
had several fentanyl patches stuck to the roof of her mouth.
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Having
adult patches stuck to their skin. This has happened when
children unknowingly rolled over skin patches that came off in
an adult’s bed.
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Finding and chewing on skin patches, just as they find and mouth
anything else that looks interesting.
The first
thing to do if you suspect an overdose is to remove the patch and
wash the skin with soap and water. Then, call the poison center
right away. The 24-hour number is
1-800-222-1222.
The poison center experts will tell you exactly what to do. If you
have to go to the hospital, the poison center will call ahead to the
emergency department to provide treatment recommendations.
It’s
important to call the poison center, even if the person seems OK.
Even after taking the patch off, some drug remains in the body. The
poison center will stay in touch with you to be sure that no
problems develop. |