The opioid drug tramadol may cause blood sugar to drop to life-threatening levels, research suggests.
Scientists analysed 12million adverse events reports collected by the US Food and Drug Administration (FDA) over 15 years.
The painkiller, marketed as ConZip or Ultram, was found to have a significant risk of hypoglycaemia, which can lead to confusion, seizures or even death.
This could be particularly dangerous for diabetics, warned the scientists from the University of California, San Diego.
These patients are already at risk of hypoglycaemia due to the blood sugar lowering medication they take.
The legal opioid tramadol could cause blood sugar to drop to life-threatening levels (stock)
Since tramadol’s approval in the US in 1995, it has often been prescribed over other opioids due to its supposed superior safety and lower risk of addiction.
However, compared to virtually every other opioid, tramadol has a 10 times higher risk of hypoglycaemia, the study found.
Other studies have linked tramadol to low blood sugar, but official health bodies do not list it as a recognised side effect.
The NHS lists very common tramadol side effects, affecting more than one in 10, as nausea and dizziness.
Common side effects, which occur in around one in 100 people, include headaches, vomiting and dry mouth.
Serious side effects are rarer still but include shallow breathing, hallucinations and seizures, officials say.
RxList, the online resource of US prescription medications, also does not mention hypoglycaemia as a tramadol side effect.
To find out more about it’s risks, the researchers analysed voluntary reports of side effects from drugs sent to the FDA by patients between January 2004 and March 2019.
‘The impetus was the recent dramatic surge in tramadol popularity and prescription,’ study author Dr Tigran Makunts said.
‘We wanted to have an objective data-driven look at its adverse effects and bumped into a dangerous, unlisted and unexpected hypoglycaemia.’
HOW AMERICA GOT HOOKED ON OPIOID DRUGS
Prescription opioids and illicit drugs have become incredibly pervasive throughout the US, and things are only getting worse.
In the early 2000s, the FDA and CDC started to notice a steady increase in cases of opioid addiction and overdose. In 2013, they issued guidelines to curb addiction.
However, that same year – now regarded as the year the epidemic took hold – a CDC report revealed an unprecedented surge in rates of opioid addiction.
Overdose deaths are now the leading cause of death among young Americans – killing more in a year than were ever killed annually by HIV, gun violence or car crashes.
Preliminary CDC data, published by the New York Times, shows that US drug overdose deaths surged 19 percent to at least 59,000 in 2016.
This is up from 52,404 in 2015, and double the death rate from a decade ago.
It means that for the first time drug overdoses are the leading cause of death for Americans under 50 years old.
The data lays bare the bleak state of America’s opioid addiction crisis fueled by deadly manufactured drugs like fentanyl.
The team also looked at other prescribed opioids, similar-acting non-opioid drugs – like serotonin – and NMDA receptors – such as ketamine.
Only tramadol was found to have a significant risk of hypoglycaemia. The opioid methadone was found to cause the side effect but to a lesser extent.
Methadone is commonly prescribed to help people overcome a heroin addiction.
Although the study found a link between tramadol and hypoglycaemia, the researchers stress a larger trial is required to establish any connection.
‘The takeaway message is to warn physicians about the likelihood of low blood sugar, in particular if the patient is predisposed to diabetes,’ lead author Dr Ruben Abagyan said.
‘And to motivate research about the unique molecular mechanism leading to that side effect.
‘It is particularly important for tramadol or methadone that are used widely and, often, chronically.’
Opioids are a class of drugs that include the illegal heroin, synthetic opioids like fentanyl, and pain relievers that are available legally on prescription, according to the National Institute on Drug Abuse (NIDA).
Patients may be prescribed legal opioids if they are suffering from chronic headaches, post-surgery pain or discomfort brought on by cancer, the American Society of Anesthesiologists reports.
All these drugs interact with opioid receptors on nerve cells. This blocks pain messages from being sent through the spinal cord to the brain.
Opioids are generally safe when taken over the short term and prescribed by a doctor. However, they can be addictive due to the euphoric feeling they cause.
Overdosing can cause a person’s breathing and heart rate to become dangerously slow.
More than two million Americans misuse opioids and over 130 die every day from a related overdose, NIDA statistics show.
In 2017, the US Department of Health and Human Services declared the opioid crisis a public health emergency.
In terms of legal, available opioids, the UK has less than the US or Germany but had one of the fastest rates of growth over the three years up to 2016, the BBC reported.
Some worry the UK is on the verge of an opioid crisis, with drug use and abuse on the rise, particularly in deprived parts of northern England.