Do not underestimate the potency of medicine patches that are for external use only.
A common misconception of consumers is that external-use medicine patches can be applied without due regard to their dosage - indeed, to the extent, the more the better.
This could not be more mistaken and potentially dangerous in the use of medicine patches, the Consumer Council warned in a report in the February issue of CHOICE.
Despite the long history in use of medicine patches, a better understanding of how they work will help raise the awareness of users to ensure safety.
In a nutshell, they work by having the medicines stored in patches and released to the users' body through the skin.
The distinct characteristic of transdermal medicine patches is that medicine can enter directly the blood capillary under the skin.
Whereas, in the case of drugs which are taken by oral route, they may be absorbed through the small intestine and carried through the hepatic portal vein into the liver where they are metabolized. In the process, the concentration of the drug may be reduced.
So, it is obvious that medicine patches are no less medicines whose dosage should be strictly observed to avoid drug overdose.
Consumers should consult healthcare professional if they are feeling unwell. Should you need to consult a doctor while using medicines, inform the doctor about your drug history including any medicine patches used, to prevent prescription of similar oral medicines to prevent drug overdose.
Consumers are advised to use medicine patches according to doctors' and pharmacists' instructions and the drug labelling, and take heed of the following:
- Do not add or reduce the number of patches to be used on your own.
- Do not cut transdermal medicine patches (which have a sustained release mechanism) into any sizes or shapes as otherwise the medicines may be released more rapidly than they should be.
- If a patch is found to be damaged, remove it from the skin and wash the affected area with water and seek doctors' advice, if necessary.
- Some patches are heat sensitive: if a patch is too close to a heat source, the medicine may be released rapidly, posing a risk of intoxication.
- Do not apply soap, ointment or cosmetics on the patch or the area around the patch.
- Replace the patch according to doctors' and pharmacists' or drug inserts' instructions. Do not put on any new patch when the old patch has not been removed.
- Do not put a new patch on the same area of the skin covered by the old patch so as to avoid irritation to the skin.
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