Leonard 2017: one oxycodone dose and a severe reaction on low-dose naltrexone

What they tested

Emergency doctors described one patient taking low-dose naltrexone (LDN) for multiple sclerosis. LDN is a small daily dose of naltrexone that has been tried in several small studies for inflammatory conditions. In hospital he was given one 5 mg dose of oxycodone, an opioid painkiller.

The authors set the case against what drug-interaction tools in electronic health records say about this pair. Those tools flag a risk of opioid withdrawal, not a stronger opioid effect.

What they found

After the single dose of oxycodone, the patient became obtunded (deeply drowsy) and did not respond to painful stimuli. He needed repeated doses of naloxone, the opioid overdose reversal drug, then a naloxone infusion, and spent 1 night in intensive care.

He responded well to naloxone and was discharged in satisfactory condition.

The authors offer an explanation: LDN is thought to increase the body's own opioid receptors, which may make some people more sensitive to opioid drugs, not less.

Limits

• It describes one person, so it can't show how often this happens or prove that LDN caused the reaction.
• The idea that LDN makes people more sensitive to opioids is a theory the authors put forward. The report didn't test it.

What it means if you're considering naltrexone

People on LDN, and doctors treating them, can't assume a small naltrexone dose will blunt an opioid painkiller. In this case it seemed to do the opposite. Because interaction software flags the pair only as a withdrawal risk, a prescriber may not expect over-sedation.

A single case report is weak evidence. It shows the combination can be unpredictable, not that it is usually dangerous.