Some common pain relievers may increase the risk of cardiac arrest, according to a new study from Denmark.

In the study, researchers found a link between the use of nonsteroidal anti-inflammatory drugs (NSAIDs) — including ibuprofen — and an increased risk of cardiac arrest, which is when the heart suddenly stops beating.

The findings add to those of previous research, which has also found a link between NSAID use and a higher risk of heart problems, including heart attack, stroke and heart failure. The new study is the first to look specifically at the impact of NSAIDs on cardiac-arrest risk.

"The findings are a stark reminder that NSAIDs are not harmless," study author Dr. Gunnar Gislason, a professor of cardiology at Copenhagen University Hospital Gentofte, said in a statement. People should be aware of the link, so that they can balance the benefits of taking one of these drugs against the risks, the researchers said. "NSAIDs should be used with caution and for a valid indication," Gislason said.

The researchers recommended that people not take more than 1,200 milligrams of ibuprofen (or six 200-mg tablets) per day. [Top 10 Amazing Facts About Your Heart]

The U.S. Food and Drug Administration previously warned that NSAIDs, particularly at higher doses, may increase people's risk of heart attack or stroke. Consumers who use these drugs should take the lowest dose that works, for the shortest time possible, and people with heart disease or high blood pressure should speak with a doctor before using NSAIDs, the FDA advises.

In the new study, the researchers analyzed information from more than 28,000 people in Denmark who had a cardiac arrest somewhere other than a hospital during a 10-year period.

The researchers looked at each person's use of NSAIDs within the 30-day period immediately before his or her cardiac arrest, called a "case period." They compared that use to the person's use of NSAIDs during another 30-day period before the case period.

To identify NSAID use, the researchers looked at whether people had redeemed a prescription for NSAIDs, including diclofenac, naproxen, ibuprofen, rofecoxib and celecoxib. (In Denmark, most of these drugs are available only by prescription.) The researchers calculated whether a patient would have been taking NSAIDs during the case period by using information about the daily dose of the treatment and the number of tablets in the prescription.

Among the patients in the study, 3,376 were treated with an NSAID during the 30-day period before their cardiac arrest.

The use of ibuprofen was linked with a 31 percent increase in the risk of cardiac arrest, and the use of diclofenac was linked with a 50 percent increase in the risk of cardiac arrest. The researchers did not find a link between the use of naproxen, celecoxib or rofecoxib and the risk of cardiac arrest, but this might have been because these drugs were used less commonly, the researchers said. [5 Surprising Facts About Pain]

The researchers noted that their study found only an association between the use of these pain relievers and the risk of cardiac arrest, and thus it cannot prove that taking NSAIDs caused a person's cardiac arrest. But because the study compared each person's use of NSAIDs during the case period to that same person's use during another period, this takes into account many factors that might otherwise differ among different people, such as the presence of chronic diseases. However, the study could not account for temporary changes that might happen to a person, such as the occurrence of an acute disease, the researchers said.

In addition, the study obtained information only about NSAIDs that people took as prescription drugs, so the researchers don't know whether some people were taking over-the-counter NSAIDs. (In Denmark, ibuprofen is the only NSAID sold over the counter.)

The study is published in the March issue of European Heart Journal-Cardiovascular Pharmacotherapy.

Original article on Live Science.