Brand Name: Corvert
Active Ingredient: ibutilide fumarate
Indication: Corvert is used to rapidly convert atrial fibrillation or atrial flutter to sinus rhythm.
Company Name: Pharmacia & Upjohn
Introduction
Corvert (ibutilide fumarate), marketed by Pharmacia & Upjohn, is an antiarrythmic drug with predominantly class III characteristics. Class III antiarrythmic drugs prolong cardiac action potentials and increase atrial and ventricular refractoriness. It differs from other class III drugs in its mechanism of action.
How It Works
Corvert delays repolarization by activating a slow, inward sodium current. Other class III antiarrythmic drugs delay repolarization by blocking the outward flow of potassium.
Corvert (ibutilide fumarate): Clinical Study Results
Several clinical trials have demonstrated Corvert to be an effective means of converting atrial fibrillation or atrial flutter to sinus rhythm.
Four clinical studies were conducted that examined the efficacy of Corvert in converting atrial fibrillation and atrial flutter to normal, sinus rhythm. The first two studies included 466 patients who had had atrial flutter or atrial arrythmia for 3 hours to 90 days. The third trial studied 319 patients who had arrythmia for less time (3 hours to 45 days) and compared the efficacy of Corvert with that of sotsiol.
Lastly, the efficacy of Corvert (ibutilide fumarate) was assessed in 302 patients experiencing atrial fibrillation or atrial flutter, lasting one hour to three days, that occurred one to seven days after undergoing coronary artery bypass grafting (CABG) or valvular surgery.
The first two trials were randomized, double-blind, and placebo-controlled in design. In one study, a single 10-minute infusion of Corvert 0.005 to 0.025 mg/kg was evaluated in parallel patient groups. On average, the best results were observed in patients who received higher doses, with 43% to 48% of patients in the groups that were administered 0.015 mg/kg or 0.025 mg/kg converting to sinus rhythm compared to 2% of the placebo group. In patients who achieved sinus rhythm, onset of normal rhythm occurred, on average (70% of patients), within 30 minutes of the start of infusion. In the other study, two infusions of Corvert were administered.
An infusion of 1.0 mg was followed by a second infusion of 0.5 mg or 1.0 mg ten minutes after completion of the first. This method of administration was more effective in patients with atrial flutter as opposed to those with atrial fibrillation. Ninety minutes after the start of infusion, 63% of patients with atrial flutter achieved conversion compared to only 25% of patients with atrial flutter. These studies also demonstrated that patients responded better to Corvert (ibutilide fumarate) the more recent the onset of their arrythmia. For patients with arrythmias for less than 30 days, response rates were 42% and 50% for atrial fibrillation and flutter, respectively, compared to 16% and 31% of those with more chronic arrythmias.
In a third trial, patients were randomized to receive either sotsiol (1.5 mg/kg) or Corvert (1 mg or 2 mg). The results demonstrated Corvert to be superior to sotsiol in converting both atrial fibrillation and atrial flutter. Among those patients with atrial flutter, 55% and 70% who had been administered 1 mg and 2 mg of Corvert (ibutilide fumarate), respectively, converted compared to 18% of the group who received sotsiol. Patients presenting with atrial fibrillation responded better to the 2 mg dose (43%) than to the 1 mg dose (22%), and only 10% converted after sotsiol administration.
The last study focused on patients experiencing atrial arrythmias soon after undergoing CABG or valvular surgery. The patients had atrial flutter or atrial fibrillation for 1 hour to three days, were randomized to receive two 10- minute infusions of placebo or 0.25, 0.5, or 1.0 mg of Corvert (ibutilide fumarate). Among patients with atrial flutter, conversion rates at 90 minutes after infusion were: placebo 4%, 0.25 mg Corvert 58%, 0.5 mg Corvert 61%, and 1 mg Corvert 73%. Among patients with atrial fibrillation, conversion rates at 90 minutes after infusion were: placebo 20%, 0.25 mg Corvert 28%, 0.5 mg Corvert 42%, and 1 mg 44%. These results support the findings of the first two trials, which indicated that Corvert is most effective in patients with atrial fibrillation and with more recent onset arrythmia.
What the Patient Should Know
Certain cardiovascular adverse events may occur after taking Corvert (ibutilide fumarate). These include ventricular extrasystoles, nonsustained monomorphic ventricular tachycardia (VT), nonsustained polymorphic VT, and tachycardia. Other side effects include headache and nausea.
Jennifer is a clinical pharmacologist. She helps doctors of all medical specialties choose medications. Jennifer consults about drug dosage, interactions, and side effects.