Adverse event monitoring poorer in patients on amiodarone vs dofetilide
Monitoring of adverse events is lower in ambulatory patients on amiodarone than in those on dofetilide, a recent study has found. Improving the monitoring of such agents may help reduce the risk of morbidity in this population.
In total, 100 patients (amiodarone: n=50; dofetilide: n=50) were included in the analysis. Average rates of 55 percent and 57 percent were recorded for baseline and follow-up amiodarone monitoring parameters, respectively. The corresponding rates for dofetilide monitoring were 99.6 percent and 85 percent.
After prescribing amiodarone to patients, a statistically significant difference was observed in abnormally elevated thyroid-stimulating hormone levels (8–30 percent; p≤0.005). Furthermore, an increase in QTc interval by >15 percent was seen in 12 percent of patients taking dofetilide.
This study included patients prescribed amiodarone or dofetilide for a 2-year period to assess whether they were being monitored according to package labeling and guideline recommendations for adverse events. Those with ventricular arrhythmias, prescribed >1 antiarrhythmic agent, or received antiarrhythmic monitoring outside the healthcare system were excluded.
Frequency of baseline and follow-up monitoring recommendations for patients receiving amiodarone or dofetilide was the primary outcome, while secondary outcomes were the rates of adverse drug events.
“Published studies state that adherence to regular laboratory assessments for antiarrhythmic drugs is as low as 20 percent,” the authors said. “Monitoring adherence is important as other studies have shown that up to 93 percent of patients on amiodarone experience an adverse drug event leading to a potentially lethal event.”