Beta blockers were found to offer no additional survival benefit for heart attack survivors who take two other medicines as prescribed, according to a new study involving Monash University’s Centre for Medicine Use and Safety.

Heart-attack patients are usually prescribed beta blockers, ACE inhibitors and statins to help prevent a second attack and death. However, the study, in collaboration with the University of North Carolina at Chapel Hill, has challenged the belief that many heart-attack survivors need to take all three medicines to reduce their risk of death.

Published in the Journal of the American College of Cardiology, the study examined the consequences of using some of the guideline-recommended medicines but not others.

Researchers, led by Assistant Professor at the University of North Carolina, Gang Fang, PharmD PhD, followed more than 90,000 United States Medicare patients aged 65 or older who had suffered a heart attack and were prescribed a beta blocker, ACE inhibitor (or an angiotensin receptor blocker) and statin. Patients who only took the ACE inhibitor (or an angiotensin receptor blocker) and statin as prescribed were no more likely to die than those who took all three medicines.

"We found that as long as patients took their ACE inhibitors and statins as prescribed, patients appeared to gain no additional survival benefit by being adherent to their beta blocker," Monash Associate Professor Simon Bell said.

However, Associate Professor Bell urged caution. "Patients should not stop taking beta blockers - or indeed any prescription medicine - without consulting their doctor first. Doctors and pharmacists should emphasise the importance of continuing both statins and ACE inhibitors. Our study found that patients who were non-adherent to their ACE inhibitor or statin had higher rates of mortality."

The research team followed for six months heart-attack survivors who filled prescriptions for all three medicines to study how well they adhered to their prescription regimen. The team then followed the patients for up to 18 months to see how many died during that time.

Only about half of the patients (49 percent) took their medicines as prescribed, the researchers found. Six months after their heart attack, about half the patients in the study had become non-adherent to at least one of their medicines.

For patients who took all three medicines as prescribed, the mortality rate at one year was 9.3 percent. For patients who adhered to their ACE inhibitor (or angiotensin receptor blocker) and statin prescription but not their beta blocker, the mortality rate was 9.1 percent, a statistically insignificant difference. For patients not taking any of the medicines as prescribed, the mortality rate was 14.3 percent.

The authors noted that older people with several medical conditions prescribed multiple medicines may find it challenging to maintain complex medicine regimens.

“This is especially true of older people who are likely to already be taking many different medicines,” they said.