Precipitated Withdrawal

Medications such as buprenorphine and naltrexone have high affinity for the opioid mu receptor. If they are given while traditional opioids still occupy some of the receptors, they will displace those opioids. Since naltrexone is an antagonist, and buprenorphine only a partial agonist, when traditional opioids are displaced by these medications, the patient will instantly go from feeling the effects of a full agonist to feeling no activity (naltrexone) or only a little (buprenorphine).  Thus, they will feel like they are in withdrawal. This can happen when a patient is started too early on buprenorphine or naltrexone when opioids still occupy opioid receptors; this is called precipitated withdrawal  and is very uncomfortable for patients.