Avandia users could face increased risk of heart attack, says HSA
THE Health Sciences Authority (HSA) yesterday said it will significantly limit the use of a popular diabetes drug because users could face an increased risk of heart attacks.
The move follows a decision on Thursday by health regulators in Europe to withdraw the drug, and those in the United States to severely restrict its use, after a three-year review of its heart risks.
The drug rosiglitazone, which is marketed by GlaxoSmithKine (GSK) as Avandia, has been used in Singapore since 2000 to treat Type 2 diabetes.
A person with diabetes has an elevated amount of glucose in his blood. Insulin is a hormone that helps regulate blood glucose. Patients with Type 1 diabetes cannot produce insulin at all, while patients with Type 2 diabetes are resistant to the effects of insulin.
Avandia helps Type 2 diabetics to increase insulin sensitivity, thereby controlling blood sugar levels.
The HSA has received six reports of adverse reaction associated with the drug. But in most of these cases, it could not be determined if Avandia was the direct cause of the heart problems as the patients had pre-existing heart problems.
Diabetic patients are usually on multiple medications, and this makes it more difficult to attribute any increase in cardiovascular risk to any specific medicine. Diabetic patients are also predisposed to an increased risk of cardiovascular disorders.
Patients who have been prescribed Avandia should consult their doctors if they have concerns about using it. HSA added: “Patients should not stop taking their medicine unless advised by their doctors.”
The drug will now be strictly disallowed for patients with heart problems such as acute coronary syndrome, ischaemic heart disease and heart failure.
It is not recommended for those with peripheral arterial disease, a condition where plaque builds up in the arteries that carry blood around the body.
Additionally, the drug should only be used after a patient has failed at least two other anti-diabetic therapy options.
About 9 per cent of Singaporeans have diabetes, with the majority above the age of 40. Type 2 diabetes is more common here and affects up to 90 per cent of diabetics.
Avandia was initially a popular choice for doctors and considered the secondor third-line choice for treating Type 2 diabetes, said Dr Chia Su-Ynn, consultant endocrinologist at The Endocrine Clinic in Mount Elizabeth Medical Centre.
“It is an easy drug because it comes in tablet form and needs to be taken only once, at most twice, a day. It is also generally well-tolerated and efficacious in lowering blood sugar,” she said.
But it is expensive, with each tablet costing about $3 compared to other types of diabetes drugs that could cost about 10 cents a pill. This is because the patent for Avandia has not expired.
Its use waned after a report in 2007 warning of the possible risks. “Most doctors in Singapore reduced their use of the drug significantly after the watershed article was published,” said Dr Chia.
But she added that Avandia can still be an effective treatment. “It is important not to over-sensationalise the findings,” she said.
There is currently one other drug in Singapore – pioglitazone – which belongs in the same class as rosiglitazone, said Dr Loh Keh Chuan, consultant endocrinologist at the Loh Keh Chuan Diabetes, Thyroid & Hormone Clinic, at Mount Elizabeth Medical Centre.
“With the availability of pioglitazone, most doctors will prefer to use it in Singapore as there have not been reports of increased cardiovascular risks,” he said.
Housewife D. Chua, 70, said she used Avandia for 10 years before switching to another drug three months ago. She became aware of its potential risks in 2008 when the Singapore General Hospital sent a note to its patients informing them about it.
But she continued to take it. “I felt okay taking the drug but as more reports surfaced, I became uncomfortable and consulted my doctor about it.”