SOURCES: Stefan Hohnloser, M.D., professor, cardiology, J.W. Goethe University, Frankfurt, Germany; Gregg Fonarow, M.D., professor, cardiology, University of California, Los Angeles; May 5, 2015, European Heart Journal, online
TUESDAY, May 5, 2015 (HealthDay News) -- Taking the heart drug digoxin may increase the risk of premature death in patients with an irregular heartbeat and in those suffering from heart failure, German researchers report.
In the review of published studies on the subject, patients treated with digoxin had a 21 percent increased risk of early death overall from any cause, compared with patients not taking the drug. Among patients with the irregular heart rhythm known as atrial fibrillation, researchers found a 29 percent greater risk of premature death, while the increased risk was 14 percent among heart failure patients.
"Digoxin should be used with great caution," said lead researcher Dr. Stefan Hohnloser, a professor of cardiology at the J.W. Goethe University in Frankfurt.
"There are better drugs for many patients, for instance in those who receive the drug for atrial fibrillation," he said, which include beta blockers and calcium channel blockers.
"If digoxin is used, careful monitoring of patients for digoxin blood levels seems mandatory," Hohnloser said.
The report was published online May 5 in the European Heart Journal.
Dr. Gregg Fonarow, a professor of cardiology at the University of California, Los Angeles, said, "Digoxin has been used in clinical practice for many decades to treat patients with atrial fibrillation."
However, clinical trial data about the use of digoxin for atrial fibrillation has been very limited, and its safety and effectiveness in these patients remains controversial, he added.
Several studies have suggested that digoxin may be associated with an increased risk of premature death, Fonarow said. But those findings may be inaccurate because digoxin is more likely to be used in patients with severe heart failure and in those who have not responded to other heart drugs, he explained.
The same can be said of this new study, Fonarow suggested. "These findings are hypothesis-generating rather than definitive, as combining multiple studies together does not reduce the potential of being misleading," he said.
Current guidelines favor other medications for atrial fibrillation, Fonarow said. "However, patients with atrial fibrillation should not alter their medications without speaking to their physician and carefully weighing the risk and benefits of the different options available," he advised.
Given the controversy regarding the safety and effectiveness of digoxin in patients with atrial fibrillation, clinical trials of digoxin are needed, Fonarow said.
For the study, Hohnloser and colleagues analyzed 19 previously published studies that looked at the connection between digoxin use and death from atrial fibrillation and heart failure.
The studies were published between 1993 and 2014, and included more than 325,000 patients.
Digoxin has been used for decades around the world to treat heart problems. Made from the foxglove plant (digitalis), it helps the heart to beat more strongly and with a more regular rhythm. The correct dose of the drug, however, can be difficult to determine, the researchers said. Giving too much can be dangerous, and frequent blood tests are needed to ensure patients aren't getting an unsafe amount, they explained.
In addition, digoxin may not mix well with other drugs, leading to dangerous overdoses. A recent trial of another heart drug, dronedarone (Multaq), in atrial fibrillation patients was stopped early because of deaths among those taking dronedarone.
Of the 13 patients taking dronedarone who died, 11 were also taking digoxin, Hohnloser said. These deaths were most likely caused by an interaction between the drugs, the researchers reported.
Visit the American Heart Association for more on atrial fibrillation.