Common painkillers such as ibuprofen are linked to an increased risk of irregular heartbeat, experts have said.
Non-selective non-steroidal anti-inflammatory drug have been found in previous studies to increase the risk of heart attack and stroke if taken regularly.
Now experts writing in the British Medical Journal say the drugs together with a group of anti-inflammatories known as selective COX-2 inhibitors could increase the risk of abnormal heart rhythm.
The condition (also known as atrial fibrillation) can increase the chances of suffering a stroke, heart failure and death.
Danish researchers analysed data for more than 32,000 patients with abnormal heart rhythm who were diagnosed between 1999 and 2008, and compared them with healthy people.
The group was broken down according to whether people used the drugs over the long term or had started them more recently.
Compared with people who did not take the drugs, recent users were about 40 per cent more likely to suffer irregular heart beat if they were on NSAIDs and 70 per cent more likely if they were on COX-2 inhibitors.
This equates to about four extra cases of atrial fibrillation per year per 1,000 new users of NSAIDs and seven extra cases among new users of COX-2 inhibitors.
The risk appeared highest in older people. Those taking COX-2 inhibitors for rheumatoid arthritis were at particular risk.
The authors concluded: “Our study thus adds evidence that atrial fibrillation or flutter need to be added to the cardiovascular risks under consideration when prescribing NSAIDs.”
Natasha Stewart, senior cardiac nurse at the British Heart Foundation, said: “This study suggests a link between common pain relief medicines and an increased risk of developing particular abnormal heart rhythms, known as atrial fibrillation or atrial flutter.
“However, it’s important to note that the overall risk from these drugs and abnormal heart rhythms is still small.
“Those most at risk were the elderly or people with other illnesses, such as chronic kidney disease or rheumatoid arthritis.
“The study also noted that NSAIDs, which include ibuprofen, carried a lower risk than drugs in the COX-2 inhibitor group. Doctors are rightly already cautious about prescribing COX-2 inhibitors for people with heart and circulatory disease or at high risk of developing it.
“As with any drug, there are risks and benefits to be had. Talking these through with your GP will help ensure the benefits outweigh any risks involved.”