Ibutilide Fumarate

Description

DESCRIPTION Ibutilide fumarate injection is an antiarrhythmic drug with predominantly class III (cardiac action potential prolongation) properties according to the Vaughan Williams Classification. Each milliliter of ibutilide fumarate injection contains 0.1 mg of ibutilide fumarate (equivalent to 0.087 mg ibutilide free base), 0.189 mg sodium acetate trihydrate, 8.9 mg sodium chloride, hydrochloric acid and/or sodium hydroxide to adjust pH to approximately 4.6, and water for injection. Ibutilide fumarate injection is an isotonic, clear, colorless, sterile aqueous solution. Ibutilide fumarate has one chiral center, and exists as a racemate of the (+) and (−) enantiomers. The chemical name for ibutilide fumarate is Methanesulfonamide, N-{4-{4-(ethylheptylamino)-1 -hydroxybutyl}phenyl}, (+)(−), (E)-2-butenedioate (1:0.5) (hemifumarate salt). Its molecular formula is C 22 H 38 N 2 O 5 S, and its molecular weight is 442.62. Ibutilide fumarate is a white to off-white powder with an aqueous solubility of over 100 mg/mL at pH 7 or lower. The structural formula is represented below: Ibutilide Fumerate Chemical Structure

What Is Ibutilide Fumarate Used For?

INDICATIONS AND USAGE Ibutilide fumarate injection is indicated for the rapid conversion of atrial fibrillation or atrial flutter of recent onset to sinus rhythm. Patients with atrial arrhythmias of longer duration are less likely to respond to ibutilide fumarate injection. The effectiveness of ibutilide has not been determined in patients with arrhythmias of more than 90 days in duration.

Dosage and Administration

DOSAGE AND ADMINISTRATION The recommended dose based on controlled trials (see CLINICAL PHARMACOLOGY: Clinical Studies ) is outlined in the Table below. Ibutilide infusion should be stopped as soon as the presenting arrhythmia is terminated or in the event of sustained or nonsustained ventricular tachycardia, or marked prolongation of QT or QTc. Recommended Dose of Ibutilide Fumarate Injection Patient Weight Initial Infusion (over 10 minutes) Second Infusion 60 kg (132 lb) or more One vial (1 mg ibutilide fumarate) If the arrhythmia does not terminate within 10 minutes after the end of the initial infusion, a second 10-minute infusion of equal strength may be administered 10 minutes after completion of the first infusion. Less than 60 kg (132 lb) 0.1 mL/kg (0.01 mg/kg ibutilide fumarate) In a trial comparing ibutilide and sotalol (see CLINICAL PHARMACOLOGY: Clinical Studies ), 2 mg ibutilide fumarate administered as a single infusion to patients weighing more than 60 kg was also effective in terminating atrial fibrillation or atrial flutter. In the post-cardiac surgery study (see CLINICAL PHARMACOLOGY: Clinical Studies ), one or two intravenous infusions of 0.5 mg (0.005 mg/kg per dose for patients weighing less than 60 kg) was effective in terminating atrial fibrillation or atrial flutter. Patients should be observed with continuous ECG monitoring for at least 4 hours following infusion or until QTc has returned to baseline. Longer monitoring is required if any arrhythmic activity is noted. Skilled personnel and proper equipment (see WARNINGS, Proarrhythmia ), such as a cardioverter/defibrillator, and medication for treatment of sustained ventricular tachycardia, including polymorphic ventricular tachycardia, must be available during administration of ibutilide fumarate injection and subsequent monitoring of the patient. Dilution Ibutilide fumarate injection may be administered undiluted or diluted in 50 mL of diluent. Ibutilide fumarate injection may be added to 0.9% Sodium Chloride injection or 5% Dextrose injection before infusion. The contents of one 10 mL vial (0.1 mg/mL) may be added to a 50 mL infusion bag to form an admixture of approximately 0.017 mg/mL ibutilide fumarate. Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration whenever solution and container permit. Compatibility and Stability The following diluents are compatible with ibutilide fumarate injection (0.1 mg/mL): 5% Dextrose injection 0.9% Sodium Chloride injection. The following intravenous solution containers are compatible with admixtures of ibutilide fumarate injection (0.1 mg/mL): polyvinyl chloride plastic bags polyolefin bags. Admixtures of the product, with approved diluents, are chemically and physically stable for 24 hours at room temperature (15° to 30°C or 59° to 86°F) and for 48 hours at refrigerated temperatures (2° to 8°C or 36° to 46°F). Strict adherence to the use of aseptic technique during...

Side Effects (Adverse Reactions)

ADVERSE REACTIONS Ibutilide fumarate injection was generally well tolerated in clinical trials. Of the 586 patients with atrial fibrillation or atrial flutter who received ibutilide fumarate injection in phase II/III studies, 149 (25%) reported medical events related to the cardiovascular system, including sustained polymorphic ventricular tachycardia (1.7%) and nonsustained polymorphic ventricular tachycardia (2.7%). Other clinically important adverse events with an uncertain relationship to ibutilide fumarate injection include the following (0.2% represents one patient): sustained monomorphic ventricular tachycardia (0.2%), nonsustained monomorphic ventricular tachycardia (4.9%), AV block (1.5%), bundle branch block (1.9%), ventricular extrasystoles (5.1%), supraventricular extrasystoles (0.9%), hypotension/postural hypotension (2.0%), bradycardia/sinus bradycardia (1.2%), nodal arrhythmia (0.7%), congestive heart failure (0.5%), tachycardia/sinus tachycardia/supraventricular tachycardia (2.7%), idioventricular rhythm (0.2%), syncope (0.3%), and renal failure (0.3%). The incidence of these events, except for syncope, was greater in the group treated with ibutilide fumarate injection than in the placebo group. Another adverse reaction that may be associated with the administration of ibutilide fumarate injection was nausea, which occurred with a frequency greater than 1% more in ibutilide-treated patients than those treated with placebo. The medical events reported for more than 1% of the placebo- and ibutilide-treated patients are shown in the following Table. Treatment Emergent Medical Events with Frequency of More than 1% and Higher than that of Placebo Event Placebo N=127 All Ibutilide N=586 Patients Patients n % n % CARDIOVASCULAR Ventricular extrasystoles 1 0.8 30 5.1 Nonsustained monomorphic VT 1 0.8 29 4.9 Nonsustained polymorphic VT - - 16 2.7 Hypotension 2 1.6 12 2.0 Bundle branch block - - 11 1.9 Sustained polymorphic VT - - 10 1.7 AV block 1 0.8 9 1.5 Hypertension - - 7 1.2 QT segment prolonged - - 7 1.2 Bradycardia 1 0.8 7 1.2 Palpitation 1 0.8 6 1.0 Tachycardia 1 0.8 16 2.7 GASTROINTESTINAL Nausea 1 0.8 11 1.9 CENTRAL NERVOUS SYSTEM Headache 4 3.1 21 3.6 In the post-cardiac surgery study (see CLINICAL STUDIES ), similar types of medical events were reported. In the 1 mg ibutilide fumarate treatment group (N=70), 2 patients (2.9%) developed sustained polymorphic ventricular tachycardia and 2 other patients (2.9%) developed nonsustained polymorphic ventricular tachycardia. Polymorphic ventricular tachycardia was not reported in the 73 patients in the 0.5 mg dose group or in the 75 patients in the 0.25 mg dose group.

Drug Interactions

Drug Interactions No specific pharmacokinetic or other formal drug interaction studies were conducted. Digoxin Supraventricular arrhythmias may mask the cardiotoxicity associated with excessive digoxin levels. Therefore, it is advisable to be particularly cautious in patients whose plasma digoxin levels are above or suspected to be above the usual therapeutic range. Coadministration of digoxin did not have effects on either the safety or efficacy of ibutilide in the clinical trials. Calcium channel blocking agents Coadministration of calcium channel blockers did not have any effect on either the safety or efficacy of ibutilide in the clinical trials. Beta-adrenergic blocking agents Coadministration of beta-adrenergic blocking agents did not have any effect on either the safety or efficacy of ibutilide in the clinical trials.

Contraindications

CONTRAINDICATIONS Ibutilide fumarate injection is contraindicated in patients who have previously demonstrated hypersensitivity to ibutilide fumarate or any of the other product components.

Pregnancy and Breastfeeding

Pregnancy Ibutilide administered orally was teratogenic (abnormalities included adactyly, interventricular septal defects, and scoliosis) and embryocidal in reproduction studies in rats. On a mg/m 2 basis, corrected for the 3% oral bioavailability, the "no adverse effect dose" (5 mg/kg/day given orally) was approximately the same as the maximum recommended human dose (MRHD); the teratogenic dose (20 mg/kg/day given orally) was about four times the MRHD on a mg/m 2 basis, or 16 times the MRHD on a mg/kg basis. Ibutilide fumarate injection should not be administered to a pregnant woman unless clinical benefit outweighs potential risk to the fetus.

Nursing Mothers The excretion of ibutilide into breast milk has not been studied; accordingly, breastfeeding should be discouraged during therapy with ibutilide fumarate injection.

Overdosage

OVERDOSAGE Acute Experience in Animals Acute overdose in animals results in CNS toxicity; notably, CNS depression, rapid gasping breathing, and convulsions. The intravenous median lethal dose in the rat was more than 50 mg/kg which is, on a mg/m 2 basis, at least 250 times the maximum recommended human dose. Human Experience In the registration trials with ibutilide fumarate injection, four patients were unintentionally overdosed. The largest dose was 3.4 mg administered over 15 minutes. One patient (0.025 mg/kg) developed increased ventricular ectopy and monomorphic ventricular tachycardia, another patient (0.032 mg/kg) developed AV block-3 rd degree and nonsustained polymorphic VT, and two patients (0.038 and 0.020 mg/kg) had no medical event reports. Based on known pharmacology, the clinical effects of an overdosage with ibutilide could exaggerate the expected prolongation of repolarization seen at usual clinical doses. Medical events (e.g., proarrhythmia, AV block) that occur after the overdosage should be treated with measures appropriate for that condition.

How Supplied

HOW SUPPLIED Ibutilide Fumarate Injection is supplied as an acetate-buffered isotonic solution at a concentration of 0.1 mg/mL that has been adjusted to approximately pH 4.6 in 10 mL clear glass, single-dose, flip-top vials. NDC 67457-366-10 carton containing single-dose 10 mL vial, 1 mg/10 mL (0.1 mg/mL). Store at 20° to 25°C (68° to 77°F). [See USP Controlled Room Temperature.] Store vial in carton until used. Discard unused portion. Manufactured for: Mylan Institutional LLC Morgantown, WV 26505 U.S.A. Manufactured by: Gland Pharma Ltd Hyderabad 500 043 India Code No.: AP/DRUGS/103/97 Revised: 12/2020 MI:IBUTIJ:R5 PSLEA-019235-04