More than 40 years ago, skin patches were introduced as an effective way of delivering drugs into the body while avoiding the problems of tablets, which have to be absorbed in the gut first meaning the dose can be reduced in strength by the time it reaches its destination.
A patch can also be useful because it avoids the gastrointestinal tract, helping anyone with stomach-related problems, where absorption can be an issue.
The patch delivers small amounts of the medication or treatment directly into the skin, where it acts locally or is absorbed into the bloodstream.
While this approach is already used to help smokers quit (nicotine patches) and women through the menopause (HRT patches), it is now available for a wide variety of conditions.