Spanish trial finds beta blockers offer no overall benefit after heart attack and may increase risk for women

A large Spanish trial has found that beta blockers, long prescribed to patients after a heart attack, did not reduce the risk of death or further heart attacks and were associated with worse outcomes for women.

The trial, involving more than 8,000 adults, reported that routine use of daily beta blocker tablets after a heart attack was ineffective at lowering the risk of death or recurrent myocardial infarction. Women treated with beta blockers had a higher rate of death, subsequent heart attacks, or hospitalisation for heart failure compared with women who did not receive the drugs.

Beta blockers have been offered for decades to the majority of patients who suffer a heart attack and are commonly continued long term. The drugs can produce side effects that include fatigue, nausea and sexual dysfunction, and many patients remain on them for life. In the United Kingdom, about 60,000 people are prescribed beta blockers each year following cardiac events, health officials estimate.

Researchers and cardiology experts described the findings as potentially practice-changing. Valentin Fuster, general director of the National Centre for Cardiovascular Research in Madrid, said the results should prompt reconsideration of international clinical guidelines and encourage a sex-specific approach to treating cardiovascular disease.

The trial's conclusions add to a growing reassessment of long-standing therapies first tested in eras before modern reperfusion techniques, high-intensity statins and other contemporary treatments became standard. Beta blockers were shown historically to reduce mortality in earlier studies, but those trials often preceded current acute care and secondary prevention strategies.

Investigators reported no overall mortality benefit and no reduction in recurrent heart attacks for the broad trial population. The observed excess of adverse outcomes among women highlights differences in treatment response that were not captured in many earlier studies, which enrolled far smaller numbers of female patients.

Experts cautioned that changes to prescribing practice and updated guidelines will require careful review by professional societies and regulators. They said the new evidence should be weighed alongside existing trial data, subgroup analyses and the individual clinical circumstances of patients, including blood pressure, heart rhythm and the presence of heart failure.

Clinicians often tailor post–heart attack therapy to the individual patient, balancing potential benefits with side effects. The new trial results are likely to prompt re-evaluation of routine long-term beta blocker use in patients without ongoing indications such as heart failure or uncontrolled arrhythmias.

Professional bodies and guideline committees were expected to examine the trial data and consider revisions that reflect contemporary care and sex-specific outcomes. The study authors and outside cardiologists urged that patients currently prescribed beta blockers not stop medication abruptly but speak with their physicians to review the risks and benefits in light of the new findings.

Further analysis of the trial data, including subgroup and long-term follow-up results, will be important to determine which patients—if any—continue to benefit from beta blockers after myocardial infarction and which groups may be exposed to harm. The results add to a broader shift toward precision and sex-specific medicine in cardiology, and could affect prescribing habits for hundreds of thousands of people worldwide.