Fentanyl can be found in the bloodstream to a significant extent for approximately 12 hours after it has been taken. However, small amounts stays in the body for a while, as it is slowly released by the body’s fat tissue.
When transitioning over from fentanyl to Suboxone (buprenorphine) it is recommended waiting at least 48 to 72 hours (two to three days) after taking fentanyl before beginning
Suboxone. This is to avoid extremely uncomfortable precipitated withdrawal symptoms.
The signs and symptoms of precipitated withdrawal include the following:
- Muscle pain
- Dilated pupils
- Suicidal thoughts
- Rapid heartbeat
- High blood pressure
Another option to avoid precipitated withdrawals is micro-dosing, which means taking small amounts of Suboxone in shorter intervals.
Note that many street opioids (e.g. oxycodone or hydrocodone) are not chemically pure and are often laced include fentanyl. This not only causes deadly overdoses but can also cause precipitated withdrawals when transitioning to Suboxone.
Generally speaking, the more time passes between the last dose of street opioids or fentanyl and Suboxone induction, the more comfortable and smooth the transition will be for the patient.