A commonly prescribed painkiller may not be as effective as once thought at easing long-term pain, experts have warned.
Opioid drug tramadol, widely prescribed for moderate to severe pain, can provide short-term relief—but new research suggests its benefits for chronic pain are 'limited'.
Danish scientists who analysed the health records of more than 6,500 patients found the drug increased the risk of serious side effects, including heart disease.
Publishing their findings in BMJ Evidence Based Medicine, the team from Rigshospitalet in Copenhagen said tramadol's potential harms 'likely outweigh' its modest benefits.
They reviewed 19 clinical trials involving patients with chronic pain and concluded that tramadol and similar opioids 'should be minimised to the greatest extent possible'.
Doctors have long warned that patients waiting months for NHS operations are often left on tramadol and other opioids for dangerously long periods, putting them at risk of addiction.
Tramadol is one of the most commonly prescribed opioid painkillers in the UK, with hundreds of thousands of NHS prescriptions issued every month.
In the US, it's the 36th most prescribed drug, with more than 16 million prescriptions issued a year.
It is typically given to patients with moderate or severe pain following surgery or injury, or to those with long-term conditions such as arthritis or back problems.
The review included five trials looking at tramadol's effect on nerve pain—which happens when the nerves themselves are damaged and can cause burning, shooting or tingling sensations.
Nine trials focused on osteoarthritis, four on long-term back pain and one on fibromyalgia. Most patients took tramadol as tablets for between two and 16 weeks.
While it did reduce pain, the effect was small and not enough to make a real difference to patients' symptoms, the researchers said.
They also found people taking tramadol were about twice as likely to experience side effects compared with those on dummy pills.
These included higher rates of chest pain, heart disease and heart failure, as well as nausea, dizziness, constipation and drowsiness.
The researchers wrote: 'Around 60 million people worldwide experience the addictive effects of opioids.
In 2019, drug use was responsible for about 600,000 deaths—nearly 80 per cent linked to opioids, and a quarter due to overdose.'
Responding to the findings, Professor Kamila Hawthorne, chair of the Royal College of GPs, said:
'GPs understand how debilitating chronic pain can be and the serious impact it has on our patients' lives.
'In the UK, GPs have been advised to limit, reduce and ideally stop prescribing tramadol for chronic pain—and not to start it for new patients.
'Treating long-term pain is often difficult because the underlying cause isn't always clear, which makes it hard to target treatment.
'As with any condition, GPs will look at the physical, psychological and social factors affecting a patient's health and come up with a plan together.
This often includes non-drug options, but access to services such as pain clinics is patchy across the country.'
It comes after research last year found the NHS had spent almost £1 billion on addictive opioid painkillers over five years.
Figures from Oxford University's OpenPrescribing.net show the cost of opioid prescriptions rose from £90 million in 2019 to £186 million in 2023, with spending expected to hit £189 million this year.
The Royal College of Surgeons has also warned that hundreds of thousands of patients are 'continuing to live in pain on waiting lists'.
Many are forced to rely on powerful drugs to get by — leaving them at risk of developing addictions that can continue even after surgery.
