Negative side effects such as confusion more than tripled in frequency for dementia residents being treated with opioid-based painkillers, according to a pair of studies presented at the 2018 Alzheimer’s Association International Conference.

Researchers from the University of Exeter, King’s College London and the University of Bergen studied 162 Norwegian care home residents who had advanced dementia and significant depression. They found side effects, such as personality changes, confusion and sedation, more than tripled in those who were assigned buprenorphine as part of their treatment pathway, compared to those on a placebo.

Opioid-based painkillers, such as buprenorphine are prescribed to up to 40% of people with dementia living in care homes, researchers found. However, people with dementia are able to get effective pain relief from smaller doses than are commonly prescribed, and may be particularly sensitive to adverse effects.

“Pain is a symptom that can cause huge distress and it’s important that we can provide relief to people with dementia,” said Clive Ballard, professor of age-related diseases at the University of Exeter Medical School. “Sadly at the moment we’re harming people when we’re trying to ease their pain. We urgently need more research in this area, and we must get this dosing right. We need to establish the best treatment pathway and examine appropriate dosing for people with dementia.”

Ballard’s team did identify one contributing factor, which is that it’s possible people with dementia over-produce the body’s natural opioids.

The study, which treated arthritis in Alzheimer’s mice, found increased sensitivity to the opioid-based painkiller morphine in mice with Alzheimer’s disease compared to those without. The Alzheimer’s mice also produced more of the body’s natural endogenous opioids such as endorphins.

When treating residents with dementia, the doses of opioid-based painkillers need to be reviewed to effectively treat pain, the researchers advised.