Sadleir 2011: pain and opioid needs when naltrexone implants come out

What they tested

Doctors looked back through the case notes of 37 patients who had naltrexone implants taken out between 2001 and 2008. The implants had been used to help people stay off opioids, amphetamines or alcohol. Reasons for removal included infection where the implant went in, not tolerating naltrexone, and needing opioids for pain relief.

Thirty-two patients had general anesthesia, four had local anesthesia and one had a spinal anesthetic. The authors looked at how much opioid each person needed around the time of surgery and how they recovered.

What they found

Opioid needs around surgery varied widely, from 0 to 100 mg of intravenous morphine equivalents (median 11.7 mg, mean 20.7 mg). The only factor linked to needing more was whether the implant was infected.

Of the patients who had general anesthesia, 44% reported moderate to severe pain after surgery, and 64% of those had a longer stay in the recovery unit.

The team saw no complications caused by increased sensitivity to opioids after the implants came out. Most patients went home by the day after surgery.

The authors concluded that worry about opioid sensitivity after removal does not seem to rule out generous opioid pain relief for these patients.

Limits

• It was a small look-back review of records from one hospital, with no comparison group.
• The implants had been used for opioids, amphetamines or alcohol, and the abstract doesn't break the results down by which drug.
• It covers surgery to remove implants, not how well the implants worked.

What it means if you're considering naltrexone

For someone with a naltrexone implant, this study suggests that having it taken out can be more painful than expected, and that the amount of pain relief needed varies a lot, especially when the implant is infected. It's one hospital's experience, so it shows what can happen rather than how often. The site's implant guide notes that no naltrexone implant is FDA-approved in the US.