Safety and Effectiveness of Ibutilide in a Community Hospital
Safety and Effectiveness of Ibutilide in a Community Hospital
To determine the safety and effectiveness of ibutilide, we conducted a retrospective study of patients in a community hospital from December 1997-January 2000, reviewing hospital and pharmacy records for 12 inpatients (aged 68 ± 13 yrs) receiving ibutilide for atrial fibrillation or flutter. The cumulative conversion rate with ibutilide 0.012 ± 0.004 mg/kg was 58%. Serious cardiovascular adverse events were documented in six patients; of those patients, five had baseline QTc intervals above 440 msec, two experienced ventricular fibrillation, and four experienced symptomatic bradycardia (range 49-60 beats/minute) requiring medical intervention. The effectiveness of ibutilide was similar to that found in previous studies. However, more complications were seen in this setting where ibutilide was used infrequently and without stringent patient selection criteria or standardized administration protocols. To ensure optimal patient care, institutions should consider implementing guidelines or education strategies to reduce the potential for serious adverse effects associated with improper screening, dosing, and monitoring of patients receiving ibutilide.
Ibutilide fumarate (Corvert, Pharmacia and Upjohn, Inc., Kalamazoo, MI) is a class III antiarrhythmic agent indicated for the treatment of new onset (< 90 days) atrial fibrillation or atrial flutter in hemodynamically stable patients. It is the first agent of this class to rely on activation of slow inward sodium currents to prolong cardiac action potential and delay repolarization. Although ibutilide offers advantages due to its efficacy and rapid onset of action, serious adverse effects complicate its use. The most serious involve polymorphic ventricular tachycardia associated with QT prolongation. Induction of torsades de pointes is thought to be dependent on QT prolongation and T wave distortion. Ibutilide is suspected of inducing this effect through its ability to cause ion channel mutations resulting in either reduced potassium current or enhanced inward sodium current within myocardial tissue.
Even though the efficacy of ibutilide was demonstrated under experimental conditions, it may be difficult to extrapolate data to various clinical settings. The conditions of usual practice typically influence the effect of therapy because health care practitioners are not using stringent research criteria for patient selection or standardized administration protocols. This is of concern because ibutilide has been associated with life-threatening adverse effects such as torsades de pointes. In most cases, dysrhythmias can be reversed or prevented if appropriate precautionary measures are taken with ibutilide use. Our study was designed to examine the safety and effectiveness of ibutilide in a community hospital.
To determine the safety and effectiveness of ibutilide, we conducted a retrospective study of patients in a community hospital from December 1997-January 2000, reviewing hospital and pharmacy records for 12 inpatients (aged 68 ± 13 yrs) receiving ibutilide for atrial fibrillation or flutter. The cumulative conversion rate with ibutilide 0.012 ± 0.004 mg/kg was 58%. Serious cardiovascular adverse events were documented in six patients; of those patients, five had baseline QTc intervals above 440 msec, two experienced ventricular fibrillation, and four experienced symptomatic bradycardia (range 49-60 beats/minute) requiring medical intervention. The effectiveness of ibutilide was similar to that found in previous studies. However, more complications were seen in this setting where ibutilide was used infrequently and without stringent patient selection criteria or standardized administration protocols. To ensure optimal patient care, institutions should consider implementing guidelines or education strategies to reduce the potential for serious adverse effects associated with improper screening, dosing, and monitoring of patients receiving ibutilide.
Ibutilide fumarate (Corvert, Pharmacia and Upjohn, Inc., Kalamazoo, MI) is a class III antiarrhythmic agent indicated for the treatment of new onset (< 90 days) atrial fibrillation or atrial flutter in hemodynamically stable patients. It is the first agent of this class to rely on activation of slow inward sodium currents to prolong cardiac action potential and delay repolarization. Although ibutilide offers advantages due to its efficacy and rapid onset of action, serious adverse effects complicate its use. The most serious involve polymorphic ventricular tachycardia associated with QT prolongation. Induction of torsades de pointes is thought to be dependent on QT prolongation and T wave distortion. Ibutilide is suspected of inducing this effect through its ability to cause ion channel mutations resulting in either reduced potassium current or enhanced inward sodium current within myocardial tissue.
Even though the efficacy of ibutilide was demonstrated under experimental conditions, it may be difficult to extrapolate data to various clinical settings. The conditions of usual practice typically influence the effect of therapy because health care practitioners are not using stringent research criteria for patient selection or standardized administration protocols. This is of concern because ibutilide has been associated with life-threatening adverse effects such as torsades de pointes. In most cases, dysrhythmias can be reversed or prevented if appropriate precautionary measures are taken with ibutilide use. Our study was designed to examine the safety and effectiveness of ibutilide in a community hospital.
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