A leading drug used by millions of people to lower blood pressure does not prevent deaths from heart attacks or other cardiovascular problems as well as other treatments, researchers said on Friday.

Atenolol, which is sold under the brand name Tenormin by drugs giant AstraZeneca, was first introduced in 1976. It is one of the most widely prescribed drugs of its kind.

But Swedish scientists have questioned its benefits after reviewing the results of nine previous studies of the drug.

“Our results cast doubt on atenolol as a suitable drug for hypertensive patients,” Professor Lars Hjalmar Lindholm, of Umea University in Sweden, said in a report in The Lancet medical journal.

Atenolol belongs to a class of drugs known as beta blockers, which are prescribed for high blood pressure, angina and to prevent repeat heart attacks. The drugs help relieve stress on the heart and slow its beat.

Lindholm and his team examined the results of four studies that compared atenolol with a placebo, or dummy pill, and five that contrasted its effects with other blood pressure-lowering drugs.

The research showed the drug was no better than a placebo in reducing deaths from heart attacks or heart disease. But in one study the drug reduced stroke more than in patients who were not receiving any treatment.

“The main finding was that atenolol could not be shown to have the same preventive effects on cardiovascular disease as other common anti-hypertension drugs,” Dr Bo Carlberg, who worked on the study, said in an interview.

“Compared with the placebo, atenolol did not decrease all-cause mortality. It did not decrease cardiovascular mortality and did not decrease myocardial infraction (heart attack),” he added.

The scientists said they were surprised there were so few studies that looked at atenolol on its own, rather than in combination with other drugs. They themselves examined the impact of atenolol only and did not look at other beta blockers.

“Atenolol should not be a first-line drug for hypertension,” said Carlberg, adding that it should also not be used as a comparative drug in studies to test the effects of new blood pressure-lowering drugs.