There have been fresh calls for restrictions on the sale of the painkiller ibuprofen after another study found it heightens the risk of cardiac arrest.
Taking the over-the-counter drug was associated with a 31% increased risk, researchers in Denmark found.
Other medicines from the same group of painkillers, known as non-steroidal anti-inflammatory drugs (NSAIDs), presented an even higher risk, according to the findings published on Wednesday in the European Heart Journal.
Diclofenac, available over the counter in the UK until 2015 and still taken on prescription, raised the risk by 50%.
“The findings are a stark reminder that NSAIDs are not harmless. Diclofenac and ibuprofen, both commonly used drugs, were associated with significantly increased risk of cardiac arrest.”
The findings are the latest to raise alarm about the use of NSAIDs. Last September a study in British Medical Journal found they were linked to an increased risk of heart failure. Previous studies have linked the drugs to abnormal heart rhythm – which can cause heart failure – and an increased risk of heart attack and stroke if taken regularly.
Gislason urged people with heart problems to avoid ibuprofen and other NSAIDs. “NSAIDs should be used with caution and for a valid indication. They should probably be avoided in patients with cardiovascular disease or many cardiovascular risk factors,” he said.
Gislason suggested they should only be taken after consulting a doctor. “Over-the-counter NSAIDs should only be available at pharmacies, in limited quantities and in low doses,” he said.
He added: “The current message being sent to the public about NSAIDs is wrong. If you can buy these drugs in a convenience store then you probably think: ‘They must be safe for me.’
“Our study adds to the evidence about the adverse cardiovascular effects of NSAIDs and confirms that they should be taken seriously and used only after consulting a healthcare professional.”
The Danish investigators studied data on almost 29,000 patients who suffered an out-of-hospital cardiac arrest recorded in Denmark between 2001 and 2010. They found that use of any NSAID raised the likelihood of cardiac arrest by 31%.
The researchers speculated that the results could be explained by the effect of the drugs on the cardiovascular system, as they influence platelet aggregation and the formation of blood clots. They may also cause arteries to constrict, increase fluid retention and raise blood pressure.
Gislason said people should not take more than 1,200mg of ibuprofen in one day.
The Proprietary Association of Great Britain, the trade body representing manufacturers of over-the-counter medicines said the study had “several limitations,” and insisted that NSAIDs are safe.
John Smith, its chief executive, said: “Information about daily dosage was only based on estimates rather than accurate data and didn’t account for over-the-counter use. Prescribed NSAIDs would normally contain a higher dosage than those medicines available over-the-counter and would typically be used for longer durations.”
He added: “NSAIDs available over-the-counter, such as ibuprofen, are an effective and appropriately safe way to provide short-term pain relief if used in accordance with the clear on-pack instructions and the patient information leaflet inside. NHS Choices recommends NSAIDs to help relieve pain, reduce inflammation, and bring down a temperature.
“It is important for people with a history of heart disease or other long term condition to speak to a pharmacist before taking any over the counter medicine to check for any potential drug interactions or health concerns.”