A 65 y/o patient with ESRD and advanced Type 1 Diabetes complains of severe pain in her lower extremity secondary to lack of blood flow and necrosis. She has been taking oxycodone/acetaminophen (Percocet) 10mg/325mg TID scheduled, which is providing her no relief.
The physician would like to add fentanyl 50mcg in addition to scheduled Percocet to help relieve her symptoms. However, there is concern about possible diversion at the participant’s home, which is why her Percocet is co-mingled in her MAC, and why the physician wants to use a topical agent to be able to evaluate use.
While the participant is in severe pain, her current total daily morphine equivalent dose on Percocet 10/325 TID is 45mg. The total daily morphine equivalent dose of fentanyl 50mcg is 120mg – more than 2.5x her current dose. If used in addition to her scheduled Percocet, her total morphine equivalent dose would increase from 45mg to 165mg daily – more than 3.5x current dose. If this dose proved to be too high, the adverse effects would be difficult to reverse due to fentanyl’s long half-life (20-27 hours) and continual transdermal absorption even after the patch is removed.
Start participant instead on fentanyl 25mcg patch and change her Percocet from scheduled to PRN. Fentanyl 25mcg would provide a total daily morphine equivalent dose of 60mg, with an additional 15 to 45mg morphine equivalent dose per day provided by the Percocet, if needed. If she continues to need the Percocet around the clock in addition to her fentanyl, then consider increasing her patch to 50mcg. The participant also should receive a prophylaxis regimen for constipation, which is a common adverse effect with opioid use.
Fentanyl dose was initiated at 25mcg Q72H and Percocet frequency changed to PRN. Participant has thus far remained on recommended doses with no escalation needed.
TIP: Morphine Equivalent Dosing (MED) Calculator is available in EireneRx, to be used at the point of prescribing!