I haven't heard of using Saran wrap, but I can see no harm lifting half of it off, putting some wrap down then taping it back to the arm.
She will start adjusting more to the dosage over time, she sounds like she's getting a little too much, if you think there's a problem then peel it off for awhile, but it may not stick well afterwards.
I'm not a pharmacist but I have been prescribed
Duragesic before.
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