Beta-blockers, long considered a cornerstone drug for heart patients, may actually put some women at higher risk after a heart attack, according to a major international study.
Key Findings
- Women with normal heart function (ejection fraction above 50%) who were prescribed beta-blockers after a heart attack had:
- Higher risk of repeat heart attacks
- Increased hospitalisations for heart failure
- Nearly three times higher risk of death compared to women not given the drug
- These risks were especially high among women receiving high doses of beta-blockers.
- The same pattern was not observed in men, suggesting a strong sex-specific difference in drug response.
About the Study
- Draws from REBOOT trial: nearly 8,000 patients treated at 109 hospitals in Spain and Italy for ~4 years.
- Published in both the European Heart Journal and New England Journal of Medicine, and presented at the European Society of Cardiology Congress.
- Represents the largest-ever inclusion of women in a beta-blocker trial post–heart attack.
Why Are Women Affected Differently?
Experts suggest several factors:
- Smaller heart size: Women’s hearts and arteries tend to be smaller, making them more sensitive to medications that lower heart rate and blood pressure.
- Physiological differences: Hormonal and metabolic variations may alter how women process these drugs.
- Historical bias in research: For decades, most cardiac drug trials enrolled men, leaving women under-studied.
Dr. Andrew Freeman (National Jewish Health, Denver) noted:
“Gender has a lot to do with how people respond to medication. Some of it is size, some of it is biology, and some factors we still don’t fully understand.”
Why Beta-Blockers Are Prescribed
- Lower blood pressure and heart rate
- Reduce workload and oxygen demand on the heart
- Traditionally given after heart attacks to prevent recurrence and improve survival
But they also carry side effects: fatigue, low blood pressure, slow heart rate, mood changes, erectile dysfunction (in men).
Impact on Future Guidelines
Dr. Valentin Fuster, senior study author, said:
“These findings will reshape international clinical guidelines… and should spark a long-needed, sex-specific approach to treatment.”
