Two studies found that people with Alzheimer’s disease and taking opioid painkillers were twice as likely to develop side effects like constipation, nausea, vomiting, dizziness, confusion, hallucinations, and sleep problems. They also identified a mechanism that could explain why this happens.

In a randomized controlled trial of 162 Norwegian nursing home residents, researchers from the University of Exeter, King’s College London and the University of Bergen found a significant increase in side effects such as changes in personality changes, confusion and sedation, which can have a serious impact on the lives of people with dementia.

The team wants studies to be carried out to look at the appropriate dosage of painkillers (e.g. buprenorphine) for people with dementia.

About half of people with dementia who live in nursing homes experience pain.

Previous research has recognized that pain is often under diagnosed and poorly managed in people with dementia, impacting quality of life.

After paracetamol, opioid painkillers are frequently the second choice of treatment for clinicians in people with dementia and are prescribed to nearly 40% of people with dementia living in care homes.

They provide effective pain relief, but current recommendations do not consider that people with dementia get noticeable pain relief from doses lower than those usually prescribed, and are particularly susceptible to adverse effects.

The team studied 162 people from 47 Norwegian nursing homes who suffered from dementia and depression. In those given buprenorphine as part of their treatment, harmful side effects more than tripled. The researchers also found that those taking buprenorphine were significantly less active during the day.

According to Clive Ballard, a professor at the University of Exeter Medical School:

Pain is a symptom that can cause enormous distress, and it is important that we can provide relief to people with dementia. When we try to relieve their pain, we need more research in this area, and we need to find the right treatment. We need to establish the best course of treatment and consider the appropriate dosage for people with dementia.

Importantly, research conducted by Professor Ballard’s team and presented at the 2018 Alzheimer’s Disease International Conference (AAIC) sheds light on why people with dementia are more sensitive to opioid painkillers, suggesting that they overproduce the body’s natural opioids.

A second study in an Alzheimer’s mouse model revealed increased sensitivity to morphine (an opioid painkiller) compared to healthy mice. People with Alzheimer’s disease responded to a much lower dose for pain relief and experienced more adverse effects when the dose was increased to a normal level. Looking further, the study found that the Alzheimer’s mice produced more endorphins (the body’s natural endogenous opioids).