how long does it take fentanyl to leave your system
You can do the math. Fentanyl lozenges-approx. 7 hours. Duragesic takes a few hours to kick in and is supposed to last up to 72 hours (like how Oxycontin is supposed to last 12 hours) but most people find it lasts 36-60 hours. From my experience I've found fentanyl patches to last about 48-54 hours.