Taipei, Feb 5 (IANS): People who use pain killers for treating respiratory infections like common cold or flu may be at an increased risk of heart attack, researchers have warned.

The findings showed that using the nonsteroidal anti-inflammatory drugs (NSAID) during an acute respiratory infection could raise the risk for a heart attack by 3.4-fold.

The risk was 7.2 times higher when patients received the pain-relieving medications via a drip in the hospital.

"Physicians should be aware that the use of NSAIDs during an acute respiratory infection might further increase the risk of a heart attack," said Cheng-Chung Fang from the National Taiwan University Hospital in Taipei City.

On the other hand, when patients had an infection but did not take the drugs their risk was 2.7 times greater compared to a healthy person.

But, that dropped to 1.5 when they took the drugs while infection-free, the researchers said.

Patients seeking relief from cold and flu symptoms should consult with their doctor or a pharmacist before using NSAIDs, Fang added.

In the study, published in the Journal of Infectious Diseases, the team aimed to investigate whether two potential cardiac risk factors -- an acute respiratory infection, such as a cold or influenza, and NSAID use -- have a combined, joint effect on heart attack risk.

The researchers compared 10,000 Taiwanese patients for their risk of heart attack over time, across different bouts of respiratory illness and NSAID use.

The results revealed a stronger association with a heart attack when both the risk factors were present.

However, additional research is needed to clarify the apparent combined effect on risk and how the effect might be managed, the researchers noted.