For many diseases, medication must be taken regularly. This regular intake, an important part of so-called “compliance” (adherence to therapy), can sometimes be difficult. Patients forget to take them, for example, or the tablets are too large or crumble when they are cut into pieces. Medical professionals, physicians and the pharmaceutical industry are therefore working to develop drugs that facilitate compliance. One way to do this is with drug patches that are applied directly to the skin.
The skin allows active ingredients to pass through
Transdermal therapeutic systems, or TTSs for short, contain a drug depot that evenly releases fixed amounts of the active ingredient through the skin into the bloodstream. For an active ingredient to be delivered via the skin, certain requirements must be met. The active ingredient must be predominantly fat-soluble, but also have a water-soluble component. The molecular mass must be relatively small so that the substance can penetrate the skin layers without causing pain. And finally, even small dosages must be able to exert their effect in the body.
Avoid overdose
Whereas membrane patches were initially used to release the active substance extremely evenly, today it is primarily so-called matrix patches that facilitate the administration of medication. They contain the active ingredient in a gel or plastic from which it is slowly released. Although the release of the active ingredient is not quite as uniform as with a membrane patch, the risk of overdosing after cutting the patch is much lower here. Their use is therefore safer.
Travel patch
The classic drug patch is the scopolamine patch, which has been used to treat motion sickness since the mid-1970s. It is applied to a dry, hairless area behind the ear five hours before the start of the trip, and from there it exerts its effect against dizziness, nausea and vomiting. Because the active ingredient, scopolamine, can cause visual disturbances, it is advisable to wash your hands thoroughly after applying the patch to avoid accidentally getting the drug in your eye.
Pain patch
Pain patches on the skin are considered an ideal application for chronic pain patients. The analgesic effect lasts much longer and there are fewer side effects, such as constipation or fatigue, than with tablet administration. Absorption through the skin bypasses the gastrointestinal passage, so the active ingredient can enter the blood directly. This is also advantageous for patients with impaired liver and kidney function. Since 2001, there has been a pain patch with the active ingredient buprenorphine, which has an effect 25 to 50 times stronger than morphine. The duration of action is five to eight hours. To avoid overdosing, the minimum time intervals between two patches, which are changed every 72 hours, must be strictly observed. Instead of a nitrate spray or a capsule to bite into, nitrate patches can also be used to treat angina pectoris attacks. It must be ensured that a twelve-hour nitrate-free interval is observed so that the effect of the nitroglycerin is not weakened.
Hormone Patch
Hormone patches are now playing an increasingly important role in the ongoing discussion of hormone replacement therapy. Because the delivery of the active ingredient is continuous, the patch can be used to deliver much smaller doses. There are hormone patches with a dosage for 3.5 and 7 days. Unlike daily tablets, the patch only needs to be changed once or twice a week. Hormone patches are also available for men in menopause as a substitute for hormone treatment by injection.
Important tips
Except for nicotine patches used for smoking cessation, all Transdermal Therapeutic Systems require a prescription. Those using a medication patch should keep the following in mind:
- Do not cut or damage the patch, or the dosage may not be adhered to.
- The patch must be applied to a clean, dry skin area and changed as directed by the doctor or the package insert.
- To avoid irritation, it should always be applied to another area when changing.
- If the patch is removed, the supply of medication is immediately stopped.
- Bathing and showering is possible with plaster.
- For disposal, the plasters should be glued together so that children can not come into contact with them.
