Switching from Fentanyl to Suboxone

April 25, 2023

When switching from fentanyl to Suboxone (buprenorphine and naloxone), it’s best to put some time between your last dose of fentanyl and your first dose of Suboxone.

How long should I wait?

It is best to wait at least 72 hours (3 days) between stopping fentanyl and beginning Suboxone, to avoid precipitated withdrawal. In one study more than 22% of patients who waited less than 24 hours between fentanyl and buprenorphine suffered precipitated withdrawal.

What is precipitated withdrawal?

Precipitated withdrawal takes place when fentanyl (or another opioid) is still attached to opioid receptors at the time Suboxone is taken. Suboxone will then replace the fentanyl, causing immediate withdrawal symptoms, which can be severe. These symptoms may include:

  • Intense pain, including headache
  • Anxiety
  • Diarrhea
  • Nausea and vomiting
  • Runny nose
  • Chills and goosebumps (so-called “cold turkey”)

Fentanyl is short-lasting, so why do I have to wait so long to start Suboxone?

While fentanyl is a short-lasting opioid, it is absorbed into the body’s fat tissue and then slowly released for days following the last use of fentanyl. That means there is a slow but steady release of fentanyl happening—enough to cause precipitated withdrawals.

How can I prevent precipitated withdrawal?

To prevent precipitated withdrawal, patients need to wait until the fentanyl is almost completely cleared out of their bodies before beginning Suboxone. This can be challenging, since the person has to be in withdrawal for several days to avoid an even stronger withdrawal condition (precipitated withdrawal). Because the waiting period can be hard, a lot of patients do not wait the recommended amount of time.

However, a technique known as microdosing shows promise. In microdosing, patients are given small doses of Suboxone at short intervals to slowly replace the fentanyl molecules attached to opioid receptors with buprenorphine. This slow replacement prevents precipitated withdrawal. Oftentimes doses as small as 0.5 mg or 1 mg are taken (instead of the usual 8 mg). This can be most easily achieved by cutting the Suboxone strip into small pieces (this is harder to do with the tablet form).

Where can people be treated for opioid use disorder (OUD)?

QuickMD is the largest medication-assisted treatment service in the United States. We treat tens of thousands of patients each month from the convenience of their home via telemedicine.

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