Commonly bought over-the-counter painkillers including ibuprofen have been linked to a significant increased risk of cardiac arrest.
A 10-year Danish study of nearly 30,000 patients found the use of non-steroidal anti-inflammatory drugs (NSAIDs), including ibuprofen - commonly sold as Nurofen or Advil - was associated with a 31 per cent increased risk of a cardiac arrest.
The findings have led to calls for tighter restrictions on the sale of NSAIDs.
"Allowing these drugs to be purchased without a prescription, and without any advice or restrictions, sends a message to the public that they must be safe," said study author Prof Gunnar Gislason, professor of cardiology at Copenhagen University Hospital Gentofte in Denmark.
"Previous studies have shown that NSAIDs are related to increased cardiovascular risk which is a concern because they are widely used."
Researchers examined all out-of-hospital cardiac arrest patients in Denmark between 2001 and 2010 using the nationwide Danish Cardiac Arrest Registry.
Data was collected on all redeemed prescriptions for NSAIDs from Danish pharmacies since 1995.
These included diclofenac, naproxen, ibuprofen rofecoxib and celecoxib.
Use of NSAIDs during the 30 days before cardiac arrest was compared to use of NSAIDs during a preceding 30-day period without cardiac arrest.
Out of the 28,947 patients, more than 3300 were treated with a NSAID up to 30 days before the event. Ibuprofen and diclofenac were the most commonly used NSAIDs.
The risk of cardiac arrest was greatest among those who used diclofenac (51 per cent), while ibuprofen was associated with a 31 per cent increased risk.
Naproxen, celecoxib and rofecoxib were not associated with the occurrence of cardiac arrest.
"The findings are a stark reminder that NSAIDs are not harmless," said Prof Gislason.
"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 added.
It's thought NSAIDs exert numerous effects on the cardiovascular system, which could explain the link with cardiac arrest.
These can include the constriction of arteries that control blood flow to the heart and raising blood pressure.
Prof Gislason believes these drugs should be removed from supermarket shelves and only be available at pharmacies, in limited quantities, and in low doses.
"Do not take more than 1200mg of ibuprofen per day," he advised.
"Naproxen is probably the safest NSAID and we can take up to 500mg a day. Diclofenac is the riskiest NSAID and should be avoided by patients with cardiovascular disease and the general population," he said.
From 2018, painkillers containing codeine sold in Australia will require a prescription.
The Therapeutic Goods Administration decided last year that these products would no longer be available over the counter amid ongoing concerns about overuse and abuse of the painkiller.