Patients on weight loss jabs face a higher risk of life-threatening complications during surgery, a study has found.
Researchers said those taking drugs such as Mounjaro and Wegovy were 11 times more likely to run into potentially dangerous problems while under anaesthetic.
One is regurgitation, where food and fluid in the stomach comes back up into the throat while a patient is sedated and unconscious.
This can spill into the lungs – known as pulmonary aspiration – blocking the airways and, in the most serious cases, causing patients to suffocate.
It can also cause serious lung damage. Stomach acid can burn delicate tissue, while food or fluid entering the lungs can trigger pneumonia and, potentially, deadly sepsis.
It is the latest downside linked to the hugely popular jabs, just a month after it emerged that 216 deaths had been reported among people taking them.
Experts believe the problem could be linked to the way weight loss jabs, collectively known as GLP-1s, slow digestion.
The drugs mimic a naturally occurring gut hormone that makes food stay in the stomach for longer – one of the ways they help people feel full and eat less.
People taking weight loss jabs face a higher risk of life-threatening complications during surgery, a study suggests
But it also means that even when patients follow instructions to stop eating before an operation, their stomach may not be completely empty when they are put under.
Scientists from Guy’s and St Thomas’ NHS Foundation Trust and King’s College London analysed 47,039 patients undergoing procedures requiring anaesthetic across 119 UK hospitals.
Of these, 1,348 were taking the jabs.
Among this group, 1.4 per cent experienced regurgitation or pulmonary aspiration – equivalent to around one in 71 patients.
More than half of the incidents occurred as patients were waking up from anaesthesia, the researchers said.
By comparison, the complications occurred in just 0.12 per cent of patients not taking the drugs. One of these patients died.
That amounted to an 11-fold higher risk among those taking the jabs.
The findings could have implications for a growing number of patients, with an estimated 2.5 million Britons now using GLP-1 drugs, which are also becoming available in tablet form.
The authors, who presented the research at the Association of Anaesthetists Annual Meeting in Liverpool and published their findings in the journal Anaesthesia, said the results ‘highlight the importance of patients taking [GLP-1s] to inform their anaesthetists’.
‘As use of GLP-RAs is increasing, it remains good practice for anaesthetists to consider specifically asking patients if they are taking these medications before anaesthesia,’ they added.
Researchers also found that almost a third of GLP-1 users in the study had been told to stop taking the drugs before surgery, usually for one or two weeks.
But UK guidance recommends patients continue taking them.
This is because there is no clear evidence that briefly stopping the drugs before surgery reduces the risk – their effects on the stomach can persist even after a dose is skipped. Stopping treatment can also cause problems of its own, particularly for patients taking the drugs to control diabetes.
Instead, anaesthetists are advised to identify patients taking GLP-1s and take extra precautions where necessary to reduce the risk of stomach contents entering the lungs.
The researchers said it remains unclear whether stopping the drugs before an operation would make patients safer.
Despite the higher risk, the scientists said the overall risk of such problems remains low.
They also could not prove that the drugs caused the complications, only that there was an observed link.
And they noted that obesity and diabetes – two conditions the drugs are prescribed for – are known risk factors of the complications.
When asked to comment on the findings, a spokesman for Eli Lilly, maker of Mounjaro, said: ‘Patient safety is Lilly’s top priority. We actively monitor, evaluate, and report safety information for all our medicines and investigational molecules.
‘[The Medicines and Healthcare products Regulatory Agency’s] Summaries of Product Characteristics for Mounjaro (tirzepatide) and Trulicity (dulaglutide) warn that cases of pulmonary aspiration have been reported in patients receiving GLP-1 receptor agonists undergoing general anaesthesia or deep sedation.
‘Therefore, the increased risk of residual gastric content due to delayed gastric emptying should be considered prior to performing procedures with general anaesthesia or deep sedation.’
Novo Nordisk, makers of Ozempic and Wegovy, were also contacted for comment.
Last month, analysis of official drug safety reports found that around 150,000 suspected adverse reactions had been reported in people taking the drugs.
Around 18,000 were classed as serious, while 216 deaths had been linked to their use.
Most of the reports involved gastrointestinal problems. These can include pancreatitis, an inflammation of the pancreas, and gastroparesis, sometimes known as stomach paralysis.
Officials stressed that the reports do not prove that the medicines caused the reactions or deaths, only that they were suspected by the person making the report.
