Prescriptions for opioids rose steadily in the UK between 2006 to 2017, with 14% of patients becoming long-term users, according to a new study.

Researchers say the findings suggest older age, social deprivation, and a history of self-harm or substance abuse, are associated with increased risk of long-term opioid use.

They found that opioid prescriptions, especially for codeine, morphine, and oxycodone, all increased substantially during the course of the study.

To evaluate prescribing trends and understand the risk factors for long-term opioid use in the UK, the researchers analysed data from 1,968,742 new opioid users.

Their results indicate that overall, 14.6% of patients with new opioid prescriptions became long-term users starting in their first year.

According to the study published in the PLOS Medicine journal, a small percentage of physicians were what researchers called high-risk prescribers whose patients were 3.5 times more likely to use the drugs continually.

People were more likely to become long-term users if they were older, experiencing social deprivation, had a history of self-harm, suicide attempts, or substance or alcohol abuse, or suffering from fibromyalgia or rheumatological diseases, Dr Meghna Jani at the University of Manchester and colleagues report.

The study’s findings support the call for action for safer and more consistent opioid prescription practices in the UK to avoid the addiction epidemic seen in many other countries.

The authors point out that identifying general practices with abnormally high prescription rates through audit and feedback tools could help drive safer prescribing practices.

Dr Jani said: “Given the potential harms of these drugs, we think it is imperative to promote safe practices in prescribing opioids and reduce the variability we observed between regions, practices and prescriber.

“One way to do this would be to harmonise prescribing practices across regions through future well-researched policies.

“The other would be developing targeted interventions in high risk groups including areas of social deprivation and for those undergoing major surgery.”

Researchers conducted a retrospective cohort study using UK primary care electronic health records from the Clinical Practice Research Datalink (CPRD).

They found that the most commonly used opioids were codeine, dihydrocodeine, and tramadol.

Over a 12-year period, 2006–2017, codeine use increased from 484 to 2,456 prescriptions per 10,000 population per year.

Dihydrocodeine, tramadol, and fentanyl prescriptions increased between 2006 and 2012, and plateaued thereafter until the end of 2017.

Within the strong opioids group, oxycodone prescribing rose approximately from five to 169 prescriptions per 10,000 population per year over 12 years.

While morphine prescriptions also rose, from 18 to 422 prescriptions per 10,000 population per year between 2006 and 2017.

The authors point out a number of limitations to their study, including that it was limited to patients prescribed opioids in primary care and did not include opioids available over the counter or prescribed in hospitals or drug treatment centres.

Because CPRD data captures electronic prescription data from primary care physicians, the findings likely underrepresent overall drug utilisation of weaker opioids.

Another limitation is that in 2014 tramadol was reclassified as a schedule 3 drug, and prescriptions longer than one month were prohibited at any one time.

Therefore, the rise in prescriptions may reflect shorter prescriptions for certain medications, the researchers say.

They add: “Treatments for opioid addiction are mainly prescribed through specialist addiction centres in the UK, rather than through primary care, and are thus not available in the dataset.

“We were therefore not able to account for these in the analysis.”