New drug more effective, safe with AF patients
Updated: 2009-09-29 08:01
By Peggy Chan(HK Edition)
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HONG KONG: Patients suffering atrial fibrillation (AF) can expect to be less prone to stroke after an international study found that a new medication is much effective than the traditional therapy.
AF is a common heart rhythm disturbance and can increase the risk of stroke by up to seven times in those afflicted as compared to healthy people.
Medical scientists have been waiting for such a breakthrough for over 50 years since warfarin made its medical debut, as this drug comes with serious side-effects and risks.
Although warfarin can prevent blood clot formation and thereby reduce the chance of stroke, its efficacy is easily affected by interactions with food or drugs and can lead to dangerous bleeding.
According to the Mayo Clinic's website, among the foods that can dangerously interact with warfarin are garlic, licorice and those rich in vitamin K, such as spinach, broccoli and soybeans. Drugs to avoid combining with warfarin include common aspirin, Tylenol and birth control pills.
Data showed that only 60 percent of warfarin patients could achieve the desired effect and two in 100 will have serious bleeding.
Over the past two years, international cardiologists conducted a study on the use of dabigatran etexilate, a drug commonly used to prevent blood clot formation in total knee and hip replacement surgery. Some 18,113 AF patients from 44 regions, including Hong Kong, were recruited.
The result revealed that the new medication can reduce the risk of stroke and blood clot in blood vessels by 34 percent without increasing the risk of major bleeding, as compared to using warfarin.
Dabigatran etexilate can also lower the mortality rate caused by vascular diseases by up to 15 percent and it is less susceptible to drug or food interaction.
"The study indicates that it can replace warfarin. On top of the efficacy, dabigatran etexilate has shown equally impressive safety results," said Lau Chu-pak, principal investigator of the Hong Kong center for the study.
He added the new drug can be used on patients who do not respond to warfarin and those with high risk factors such as high blood pressure and diabetes.
However, due to its acidic structure, patients with stomach bleeding are not advised to take dabigatran etexilate.
Also on the negative side of the medical ledger is the cost: the new medication costs about fifty times as much as warfarin.
But some AF patients may be willing to pay for it, like Helen Wong.
The 69-year-old woman is among the 1.3 percent of the local population afflicted with AF.
Wong feels frustrated by the frequent blood tests to adjust the dosage of warfarin and because she has to give up green vegetables, which are high in vitamin K, to prevent food interaction.
"There is no alternative at the moment. I must continue (these practices) even though is troublesome to do so," she said.
She was delighted to learn that the new drug does not require diet control.
"That's really great. I want to eat all kinds of food," Wong said.
Lau said further study will be conducted to specifically investigate the efficacy of dabigatran etexilate on Asian people.
(HK Edition 09/29/2009 page1)