Common Drugs Linked to Cardiac Arrest

June 26, 2005

Commonly prescribed drugs including some popular antibiotics may be

linked to 15,000 sudden deaths in the United States and Europe each

year, according to researchers in the Netherlands.

The drugs, including the antibiotics erythromycin and clarithromycin,

interfere with electrical activity controlling heartbeat. Researchers

at Erasmus Medical Centre in Rotterdam found they were associated with

a three-fold increased risk of sudden death due to cardiac arrest.

The findings appeared today in the European Heart Journal.

Others drugs on the risk list are cisapride and domperidone, used to

treat gastrointestinal conditions, and the anti-psychotic medications

chlorpromazine, haloperidol and pimozide.

All of the drugs prolong the heart's QTc interval - a measurement of

the electrical activity linked to the contraction of heart muscle

cells. That can cause life-threatening disruption of heart rhythms.

The findings emerged from a study of 775 cases of sudden heart death.

Researchers found that the seven drugs were probably responsible for

320 of these deaths. This equated to about 15,000 deaths per year

across Europe and the United States.

But the study's senior author, Dr. Bruno Stricker, said that although

the findings were significant, it was important to keep them in

proportion. It is normal to expect one or two sudden cardiac deaths

per thousand of the population each year in Western countries.

The risk for people taking the drugs rose to around three per thousand.

" These drugs are vital treatments for serious conditions in many

cases, so it is essential that patients should not stop taking them on

their own initiative, " said Dr. Stricker, who is also a senior medical

officer at the Inspectorate for Healthcare in The Hague.

" If they are concerned they should talk to their doctor. "

The drugs have all previously been implicated in abnormal heart

rhythms (arrhythmia). But the new study is thought to be the first to

investigate links with sudden death.

Dr Stricker said the risk of sudden heart death was highest among

those who had been on the drugs for less than about 90 days.

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