A Waikato cardiologist is warning patients not to stop using beta-blocker medication following an American study questioning the effectiveness of the drug.
A paper published in The Journal of the American Medical Association found beta-blockers did not prolong the lives of heart patients nor reduce the risk of heart attack or stroke.
Researchers at New York University followed 44,700 heart patients over 3 years and found people taking beta-blockers were no less likely to die from heart attack or stroke or be treated in hospital as a result of heart disease.
Beta-blockers can be prescribed to patients with heart disease and high blood pressure.
The drug can also be used to prevent migraines and relieve the symptoms of anxiety.
Waikato Hospital cardiologist Dr Chris Nunn said the American paper was a population-based study and had to be interpreted carefully.
Dr Nunn said numerous randomised trials showed beta-blockers benefited those who had recently suffered a heart attack, as well as patients with severe heart muscle damage.
"These two groups clearly benefit and they live longer. Beta-blockers are amongst the most powerful drugs we have protecting people in these groups."
Dr Nunn said population-based studies, such as the American paper, were valuable because they raised questions "but they do not give answers".
"A population study is not controlled in any way. It's not people you've selectively chosen and then carefully randomised one particular treatment versus another.
"The number one message is people shouldn't stop using beta-blockers. It would be dangerous to stop them abruptly and if people do have questions they need to talk to their medical practitioner."
In the year to June, Pharmac funded $18.5 million worth of beta-blocker prescriptions nationwide, including $1.487m in the Waikato.
Pharmac's medical director Peter Moodie said the American research provided important data but some of its findings had been anticipated by doctors.
Dr Nunn said he wasn't concerned by the study, adding that in the past decade "more modern" beta-blockers had been introduced "and they're the ones that have been shown to be particularly effective and protective.
"In randomised trials with people with severe heart damage, we've shown people on beta-blockers do better, live longer and have less hospital admission."
Hamilton woman Jesse Rose was prescribed a beta-blocker for chronic anxiety and said the effects were "life-changing".
Miss Rose, 24, takes one tablet twice a day and said she no longer suffered from a racing heart or sweaty hands.
"I've also been supplied other medication to treat the mental health side of things but the beta-blocker has been amazing for reducing my anxiety symptoms.
"I'd suffered from chronic anxiety for eight years and I was sceptical that any pill could take away the symptoms but I feel the medication has given me my life back. I wouldn't like to think people were put off from using beta-blockers because of one study."
What is a beta-blocker? A beta-blocker is a medicine that is often used to treat high blood pressure and heart problems.
What are some of the possible side-effects of taking the drug? Because beta-blockers slow your heart, they may make you feel tired. They may make you feel a little dizzy or lightheaded.
What about other medicines? Taking other medicines – even medicines that don't require a prescription – while you're taking a beta-blocker can cause serious problems.
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