Millions of patients could be taking a combination of drugs that puts them at risk of lethal complications, including organ damage, experts have warned.
Taking both a statin and anti-inflammatory painkillers is common among Britons, as the latter are usually given to help with side effects associated with the heart pills. But over several years, this combination dramatically increases the risk of deadly stomach bleeds and kidney damage, according to pharmacists.
In a new study, Canadian experts identified this pairing as one of 24 common drug cocktails that could leave patients vulnerable to avoidable side effects and complications. Not only can the prescription spiral increase the risk of long-term damage, but taking medications to combat the side effects of other treatments can leave the underlying cause of symptoms unexplored.
Other frequently taken combinations likely to carry risks include iron supplements and laxatives, as well as cholinesterase inhibitors for dementia symptoms and sleeping pills. Experts warned that laxatives, prescribed to treat drug-induced constipation, can cause diarrhoea and dangerous chemical imbalances, while sleeping pills have been linked to an increased risk of falls and hospital admissions among older patients.
The researchers, from the University of Toronto, found that older women were more likely than other groups to be prescribed potentially harmful cocktails.
What the researchers found
Dr Paula Rochon, a geriatrician at the O'Born Centre for Mature Women's Health and the study's first author, said these sequences of events are common but often missed in clinical practice. She said knowing what medications a patient is taking, when they were started and what for is important in order to identify possible prescribing cascades that may be problematic.
Studies suggest more than one in seven people in England take five or more prescription medicines each day. Most of these patients are elderly, as they are more likely than other age groups to suffer multiple long-term conditions.
The new study set out to investigate the extent of so-called prescribing cascades among the general population of Ontario, Canada. Researchers first examined 65 drug patterns that experts believed could put patients at risk, then used prescription records from Ontario's health data institute to work out which of these cascades occur most often in real life. From this, they identified 24 common and potentially harmful prescribing patterns.
Iron supplements and statins among the worst offenders
Writing in the British Medical Journal, the researchers said the most common pattern involved iron supplements, such as ferrous fumarate, which are known to cause constipation. Instead of reviewing the original treatment, around one in ten patients were prescribed a laxative to ease the side effect.
Another frequently observed pattern involved statins. Patients prescribed the cholesterol-lowering drugs were often then given painkillers called non-steroidal anti-inflammatory drugs, or NSAIDs, such as ibuprofen, to help ease aches and pains, rather than adjusting their statin dose.
Ian Budd, lead prescribing pharmacist at Chemist4U, said statins can cause a side effect known as statin-associated myalgia, which can present as muscle aches. "This condition is potentially serious if not recognised for what it is," he said. "Meanwhile, long term use of NSAIDs like ibuprofen may expose patients to gastrointestinal bleeding, kidney injury, and cardiovascular complications."
NHS efforts to tackle over-prescribing
The findings come amid growing efforts within the NHS to tackle problematic polypharmacy, with doctors increasingly encouraged to review whether long-term medicines remain necessary and, where appropriate, reduce medicines whose risks outweigh their benefits.
A government-led review published in 2021 found that a tenth of prescription medicines handed out by GPs are unnecessary, and called for regular checks of patients' medicines. Around one in five hospital admissions among those over the age of 65 were also found to be caused by adverse effects of medicines.
Why the cascades happen
When clinicians were asked what was driving prescribing cascades, many said they lacked sufficient time to fully investigate the cause of new symptoms. Others said they felt they had no other option but to prescribe pills because waiting lists for other treatments were too long.
The research team hope that automated clinical decision support systems will help flag these cascades in real time, prevent errors and ensure clinicians can access more details about previously prescribed medications. They added that pharmacists could also help alleviate the burden by identifying potentially inappropriate prescribing patterns before patients are exposed to further risk.
Patients should not stop taking prescribed medications without advice from a healthcare professional.
