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Use Caution With Dronedarone in Patients With CV Risk Factors: Paper


NEW YORK (Reuters Health) Jun 11 - Researchers who reviewed "all available evidence" on the safety of the antiarrhythmic dronedarone (Multag, Sanofi SA) found it increases cardiovascular risk, regardless of duration of use and across a wide spectrum of clinical cardiovascular conditions.
Dronedarone should be used with caution, particularly in patients with cardiovascular risk factors, the research team advised in a report online May 21 in the American Journal of Cardiology.
The FDA has already put out a warning about the drug.
In the new paper, Dr. Saurav Chatterjee and colleagues explain that dronedarone is a new antiarrhythmic, with an electropharmacologic profile closely resembling that of amiodarone, but with a shorter half-life and structural differences intended to minimize the adverse effects seen with amiodarone.
The U.S. Food and Drug Administration approved dronedarone in July 2009 to reduce rehospitalizations in patients in sinus rhythm who have a history of paroxysmal or persistent atrial fibrillation (AF).
In the ATHENA trial, dronedarone 400 mg bid decreased the incidence of the primary outcome of unplanned hospitalization for cardiovascular causes or death. Significant decreases in deaths from cardiovascular causes and stroke were also seen.
In the subsequent PALLAS trial, however, dronedarone increased rates of stroke, heart failure, and cardiovascular death in patients with permanent AF and cardiovascular risk factors, prompting the FDA to undertake a cardiovascular safety review of the drug.
In January 2011, the agency revised the label on dronedarone to reflect the risk of heart problems, including death, for patients with irregular heart rhythms. The agency said the drug should not be used by patients who have permanent AF. For these patients, the drug doubles the rate of cardiovascular death, stroke, and heart failure, the FDA said.
Dr. Chatterjee and colleagues conducted their own cardiovascular safety assessment of dronedarone across the spectrum of patient populations in which it has been tested by performing a systematic review and meta-analysis of seven randomized controlled trials.
These trials included a total of 10,676 patients. Comparators included standard medical therapy and/or placebo and amiodarone in one study. Outcomes included all-cause mortality, cardiovascular mortality, ventricular arrhythmias, embolic events, acute coronary syndrome, heart failure exacerbations, and hospitalization rates in the intervention versus comparator group at the end of at least three months follow-up.
The researchers report that dronedarone was associated with a trend toward worse all-cause-mortality (p=0.28), with significant heterogeneity stemming from the ATHENA trial. When data from this trial were excluded, dronedarone treatment was associated with worse all-cause mortality (p=0.009) and cardiovascular mortality (p=0.0002), without any heterogeneity, the researchers say.
An exploratory analysis excluding patients with heart failure (by excluding the ANDROMEDA) trial "removed the statistical significance of all-cause mortality (with a nonsignificant trend toward worse outcomes) but maintained the significance of cardiovascular mortality, without any heterogeneity (p=0.008)."
Similarly, when excluding patients with permanent AF by excluding the PALLAS data, the dronedarone group still had a trend toward worse outcomes for all-cause mortality and a statistically significant worse cardiovascular mortality (p=0.02).
When the researchers considered dronedarone use in trials that included paroxysmal and persistent AF and excluded permanent AF, they still didn't find an all-cause mortality benefit with dronedarone use (p=0.15). However, in this subgroup of patients, dronedarone did seem to confer a benefit in cardiovascular mortality (p=0.04), they report.
Treatment with dronedarone showed a trend toward an increased risk of heart failure (p=0.20), significant heterogeneity. However, the results became significantly worse on exclusion of ATHENA data (p=0.008) and the difference persisted even after exclusion of the ANDROMEDA data (p=0.004).
All other secondary outcomes of interest except acute coronary syndromes (encompassing unstable angina and myocardial infarction) such as ventricular tachyarrhythmias, stroke and systemic embolism, and rehospitalizations also showed nonsignificant trends toward worse outcomes, the researchers report.

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