Ellen Campbell -Grizzle - PHARMACY TODAY AN INCREASING number of persons are wearing skin patches that contain medicine to treat illnesses ranging from vomiting to high blood pressure. Most recently, a contraceptive patch as well as one to deliver nutrients were announced. It is now accepted that medicines can enter the blood steam directly through the skin and provide relief.
The transdermal (across the skin) patch represents an engineering feat. After all, the skin is designed to keep out foreign substances. However, anything that we put on the skin can be absorbed to some extent and pharmaceutical companies have used this fact to develop patches that are like small sticking plasters that adhere to the skin. Although not all drugs can be delivered by the method, it offers convenience for those patients who take their medicine in this way.
When you take tablets, the medicine is absorbed from the gut and goes into the blood stream. The body gets rid of it slowly over several hours. This results in high levels in the blood at first which drop down again until the next dose is taken. Patches result in more constant amount of the medicine being in the blood stream for the time the patch is attached.
Patches are easy to use. A lower dose is needed because the drug bypasses the stomach and avoids being broken down by the enzymes in the gut. Also, an even level of drug is maintained in the blood stream. Patients are more compliant with their medication since they usually have to contend with fewer doses. For example, the new contraceptive patch is applied three times each month at recommended intervals.
However, there are some disadvantages to using a patch. Some people are allergic to patches and skin irritation can develop. Your pharmacist will recommend that you rotate the site on the body when you apply a patch. Another major drawback is the fact that patches fall off and sometimes the patient is not aware that this has happened.
TO GET THE BEST OUT OF YOUR PATCH:
Apply to a clean area
Make sure that skin hair
has been removed
Remove the protective pad
on the medication strip
Avoid touching the medication area
Apply firmly to the skin
Rotate the area to which you apply
the patch from time to time
Periodically check to see that
the patch is in place
Dispose of your patch carefully
after removal.
Some patches are used to deliver medicines that prevent heart attacks. The nicotine in these patches is constantly available in controlled amounts. This keeps the body adequately supplied and reduces the risk of angina. The nicotine patch or gum is also used to help smoking cessation. This means that there is always a constant amount of nicotine in the blood and helps to overcome the worst withdrawal effects. You do not get the same "buzz" as inhaling on a cigarette and the idea is that you do not get addicted to the patch. There are different strengths and heavy smokers start at the strongest dose and work downward as they progress.
The transdermal patch is a convenient method of delivering several medicines. After use, remember to dispose of the patch very carefully as children may chew them. These patches can pose a great threat to your pets as well since they contain enough medication to be toxic. If you want to know more about transdermal patches, ask your pharmacist, you have the right to know!
Ellen Campbell Grizzle is the President of the Caribbean Association of Pharmacists (CAP) and Director, Information and Research, National Council on Drug Abuse (NCDA), Kingston, Jamaica.
