Wightman 2018: two cases of severe withdrawal set off by Vivitrol

What they tested

Emergency doctors described two patients with precipitated opioid withdrawal: sudden, severe withdrawal set off when an opioid blocker is given while opioids are still in the body. Both reactions followed a shot of extended-release naltrexone (Vivitrol), a long-acting blocker.

The report also reviews how this kind of withdrawal is treated, noting that no set protocols exist to guide emergency staff.

What they found

A 56-year-old woman restarted Vivitrol after a relapse to opioids. She developed a hypertensive emergency (dangerously high blood pressure) and needed a continuous intravenous drug to widen her blood vessels, clonidine and intensive care monitoring.

A 25-year-old man got the shot at the end of a twelve-day detox program during which he had kept secretly using heroin. He became agitated with altered mental status. Benzodiazepines and haloperidol didn't calm him enough, and he needed intubation (a breathing tube) with several sedative infusions.

The authors write that the risk of severe withdrawal is greater when a long-acting blocker sets it off. Recommended treatments include intravenous fluids, anti-nausea drugs, clonidine or benzodiazepines, plus care aimed at whichever organ system is affected.

Limits

• Two cases show that severe reactions happen, not how often.
• Both people had recently used opioids when they got the shot, so the report describes what can go wrong when that isn't caught.

What it means if you're considering naltrexone

For anyone starting the naltrexone shot after using opioids, these cases show why clinics require an opioid-free period first, and why the authors urge a naloxone challenge. Once given, the shot can't be removed, and withdrawal from it can be severe enough to need intensive care.