Originally Posted by Neurochic

Remember too that I said one of the issues with an non-managed change from reservoir to matrix patches is that the dose released is typically different which is why they aren't interchangeable. Your previous patches may have been releasing you a different dose - fentanyl takes up to 6 days to reach its steady state in the body so messing around with dosage can cause problems both rapidly and over a number of days.

You might just be unable to get a full 3 days out of the patches, either on a one off or regular basis. There are so many things that could be going on that you would be best to speak to your pharmacist and prescriber for advice on the best way to proceed.