Scientists found that zolpidem, which is sold under the brand name Stilnoct in the UK, is linked with a dramatic rise in the number of life-threatening cardiac events, the Daily Express reported.
Four standard dose pills a year – 35 milligrams – send the risk soaring by around 20 percent.
People taking the equivalent of 60 tablets a year could see the threat jump by half.
The study – presented to the world’s biggest cardiology conference – is the first to connect the drug with cardiovascular problems.
Scientists cannot be fully certain yet that sleeping pills are causing heart problems – and the manufacturers say there are no known adverse cardiac reactions to zolpidem.
However, the researchers say the results from a study of more than 5,000 people are sufficiently worrying for “further large-scale and in-depth investigations”.