A new study from Denmark revealed that common, and oftentimes regarded as harmless, over-the-counter pain medications could increase the risk of cardiac arrest.

The study, published in the European Heart Journal-Cardiovascular Pharmacotherapy, found that the use of nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, naproxen and diclofenac, increases the risk of cardiac arrest by 31 percent.

"The findings are a stark reminder that NSAIDs are not harmless," said Professor Gunnar H. Gislason, professor of cardiology at Copenhagen University Hospital Gentofte, Denmark and one of the authors of the study, in a press release. "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."

For the study, the researchers identified all out-of-hospital cardiac arrest patients in Denmark between 2001 and 2010 using the nationwide Danish Cardiac Arrest Registry. The researchers also collected data on all redeemed prescriptions of NSAIDs in Danish pharmacies from 1995.

They were able to identify 28,947 people who had a cardiac arrest somewhere other than a hospital. Out of those, 3,376 were treated with NSAIDs up to 30 days before their attack.

To examine the association between cardiac arrest and use of NSAIDs, the researchers compared the use of NSAIDs during the 30 days before cardiac arrest (case period) was compared to used of NSAIDs during a preceding 30 day period without cardiac arrest (control period).

The use of any NSAIDs was associated with a 31 percent increased risk of cardiac arrests. Among the different NSAIDs, diclofenac and ibuprofen have the highest increased risk of cardiac arrest with 50 percent and 31 percent, respectively. Naproxen, together with COX-2 selective inhibitors celecoxib and rofecoxib, was not associated with increased risk of cardiac arrest.

The link between increase risk of cardiac arrest and use of NSAIDs could be due to the numerous effects this kind of drugs has on the cardiovascular system. NSAIDs is known to influence platelet aggregation, which in turn cause the arteries to constrict, increase fluid retention and raise blood pressure.