Ventricular tachycardia is a very rapid beating of the upper chambers of the heart. When these chambers don't beat in the correct order, the condition is called ventricular fibrillation. These problems prevent blood from being pumped properly and can cause the heart to stop beating altogether.
Amiodarone breaks down slowly, so large amounts can remain in soft tissues when the drug is taken for a long time. This might explain its association with cancer, the researchers said. Earlier studies have shown an association between amiodarone and cancer risk, but this is the largest study to date to show a link, they noted.
For the study, Su's team followed more than 6,400 patients taking amiodarone for almost three years. Among these patients, 280 developed cancer.
Men taking high doses of the drug had a 46 percent higher chance of developing cancer than those who were neither male nor taking large doses. Anyone taking high doses had nearly twice the risk of cancer compared with people taking low doses, the researchers found.
Cancers of the digestive system, lung, liver, colon, ovaries and prostate were among the cancers associated with amiodarone, the researchers said.
For more information on amiodarone, visit the U.S. National Library of Medicine.
SOURCES: Vincent Yi-Fong Su, M.D., Taipei Veterans General Hospital, Taiwan; Gregg Fonarow, M.D., spokesman, American Heart Association, and professor, cardiology, University of California, Los Angeles; April 8, 2013, Cancer
All rights reserved