The drug is designed to treat irregular heart beat (arrhythmia), but researchers have discovered this week that it also causes a range of cancers.
Men seem to be more at risk, as do people who take high doses of the drug. In fact, those on higher doses double their risk of cancer compared to those on low doses.
Researchers at the Taipei Veterans General Hospital in Taiwan made the discovery when they profiled the health of 6,418 men and women taking the drug. During the 30 months they were tracked, 280 developed cancer.
(Source: Cancer, 2013; published online: 10.1002/cncr.27881).