Sales of opioid analgesics in the UK fell between 2015 and 2019 despite an overall global increase, according to a wide-ranging study that revealed disparities in the ability of different countries to access the drugs.

Researchers from the UCL School of Pharmacy looked a database of opioid analgesic sales in 66 countries and regions during that period across the retail and hospital sector and found worldwide sales rose from 27.52 milligram morphine equivalent (MME) per 1000 inhabitants per day to 29.51 MME per 1000/day.

In the UK however, it dropped from 706.81 MME per 1000/day in 2015 to 638.72 in 2019. In Ireland, it increased from 372.26 to 417.14. The study was published in The Lancet and the data was supplied by IQVIA.

There was a general reduction in consumption in North America and Oceania but annual increases in South America, eastern Europe, Asia and western and central Europe.

The US saw a drop from 1331.99 to 737.51 which was surprising given its well documented national struggle with opioid addiction.

The study found that in some countries such as Kazakhstan, there was low opioid consumption despite the high cancer death rate or prevalence of the disease which the researchers said could “indicate potentially inadequate access to opioid analgesics as essential pain control.”

In 2019, consumption of the drugs ranged from 0.01 to 5.40 in 17 countries and regions that had the lowest rates even though some of them had high income levels as well as cancer death rates.

“We found that while there is some improvement in a lot of countries, there are still concerningly low rates of opioid use in large parts of the world, even in numerous middle-income countries,” said Dr Wallis Lau, the study’s lead author.

“Opioids have been listed by the World Health Organization as an essential class of medicine for acute pain, cancer-related pain, and palliative care since 1977, so it is troubling that in many parts of the world, people are unable to access this medicine. There is an urgent need to tackle the global gap in opioid access.

“Some countries have low opioid analgesic consumption despite a high cancer prevalence, which could suggest inadequate access to opioid analgesics as much-needed pain control.”

Joint senior author professor Ian Wong said the findings reinforced “the need to recognise palliative care and pain relief as a global public health priority.”

But he warned it was important to avoid opioid misuse and overprescribing in countries where there is good access to opioids so patients are not “undertreated.”

Opioid use in some African and South American countries was less than one-tenth of one per cent of the rates in wealthy North American and European countries as well as Australia.

However, researchers said the drop in opioid use across North America was probably down to efforts to reduce inappropriate prescribing. That, the study said, has seen the likes of Switzerland, Germany and Spain surpass the US in sales of opioids.