SOTYLIZE SOTALOL HYDROCHLORIDE 5 mg/mL Solution, 480 mL — NDC 24338-530-48 (Billing 24338-0530-48)

12 CLINICAL PHARMACOLOGY

12.1Mechanism of Action Sotalol has both beta-adrenoreceptor blocking (Vaughan Williams Class II) and cardiac action potential duration prolongation (Vaughan Williams Class III) antiarrhythmic properties. The two isomers of sotalol have similar Class III antiarrhythmic effects, while the l-isomer is responsible for virtually all of the beta-blocking activity. The beta-blocking effect of sotalol is non-cardioselective, half maximal at an oral dose of about 80 mg/day and maximal at doses between 320 and 640 mg/day.

Sotalol does not have partial agonist or membrane stabilizing activity. Although significant beta-blocker occurs at oral doses as low as 25 mg, significant Class III effects are seen only at daily doses of 160 mg and above. In children, a Class III electrophysiological effect can be seen at daily doses of 210 mg/m 2 body surface area (BSA).

A reduction of the resting heart rate due to the beta-blocking effect of sotalol is observed at daily doses ≥90 mg/m 2 in children.

12.2Pharmacodynamics Cardiac Electrophysiological Effects Sotalol hydrochloride prolongs the plateau phase of the cardiac action potential in the isolated myocyte, as well as in isolated tissue preparations of ventricular or atrial muscle (Class III activity). In intact animals it slows heart rate, decreases AV nodal conduction and increases the refractory periods of atrial and ventricular muscle and conduction tissue. In human, the Class II (beta-blockers) electrophysiological effects of sotalol are manifested by increased sinus cycle length (slowed heart rate), decreased AV nodal conduction and increased AV nodal refractoriness.

The Class III electrophysiological effects in man include prolongation of the atrial and ventricular monophasic action potentials, and effective refractory period prolongation of atrial muscle, ventricular muscle, and atrio-ventricular accessory pathways (where present) in both the anterograde and retrograde directions. With oral doses of 160 to 640 mg/day, the surface ECG shows dose-related mean increases of 40 to100 msec in QT and 10 to40 msec in QTc [see Warning and Precautions (5.1] ) . No significant alteration in QRS interval was observed.

In a small study (n=25) of patients with implanted defibrillators treated concurrently with sotalol, the average defibrillatory threshold was 6 joules (range 2 to15 joules) compared to a mean of 16 joules for a non-randomized comparative group primarily receiving amiodarone. Twenty-five children in an unblinded, multicenter trial with supraventricular (SVT) and/or ventricular (VT) tachyarrhythmias, aged between 3 days and 12 years (mostly neonates and infants), received an ascending titration regimen with daily doses of 30, 90 and 210 mg/m 2 with dosing every 8 hours for a total of 9 doses.

During steady-state, the respective average increases above baseline of the QT c interval, in msec (%), were 2, 14, and 29 msec at the 3 dose levels. The respective mean maximum increases above baseline of the QTc interval were 23, 36, and 55 msec at the 3 dose levels. The steady-state percent increases in the RR interval were 3, 9 and 12%.

The smallest children (BSA<0.33m 2 ) showed a tendency for larger Class III effects (∆QTc) and an increased frequency of prolongations of the QTc interval as compared with larger children (BSA≥0.33m 2 ). The beta-blocking effects also tended to be greater in the smaller children (BSA<0.33m 2 ). Both the Class III and beta-blocking effects of sotalol were linearly related with the plasma concentrations.

Hemodynamics In a study of systemic hemodynamic function measured invasively in 12 patients with a mean LV ejection fraction of 37% and ventricular tachycardia (9 sustained and 3 non-sustained), a median dose of 160 mg twice daily of sotalol produced a 28% reduction in heart rate and a 24% decrease in cardiac index at 2 hours post-dosing at steady-state. Concurrently, systemic vascular resistance and stroke volume showed non-significant… [Excerpted — this section continues on DailyMed.]

12.1Mechanism of Action Sotalol has both beta-adrenoreceptor blocking (Vaughan Williams Class II) and cardiac action potential duration prolongation (Vaughan Williams Class III) antiarrhythmic properties. The two isomers of sotalol have similar Class III antiarrhythmic effects, while the l-isomer is responsible for virtually all of the beta-blocking activity. The beta-blocking effect of sotalol is non-cardioselective, half maximal at an oral dose of about 80 mg/day and maximal at doses between 320 and 640 mg/day.

Sotalol does not have partial agonist or membrane stabilizing activity. Although significant beta-blocker occurs at oral doses as low as 25 mg, significant Class III effects are seen only at daily doses of 160 mg and above. In children, a Class III electrophysiological effect can be seen at daily doses of 210 mg/m 2 body surface area (BSA).

A reduction of the resting heart rate due to the beta-blocking effect of sotalol is observed at daily doses ≥90 mg/m 2 in children.

12.3Pharmacokinetics The pharmacokinetics of the d- and l-enantiomers of sotalol are essentially identical. Absorption In healthy subjects, the oral bioavailability of sotalol is 90 to100%. After oral administration, peak plasma concentrations are reached in 2.5 to 4 hours, and steady-state plasma concentrations are attained within 2 to3 days (that is, after 5-6 doses when administered twice daily).

Over the oral dosage range 160 to640 mg/day, sotalol displays dose proportionality with respect to plasma concentrations. When administered with a standard meal, the absorption of sotalol was reduced by approximately 20% compared to administration in fasting state. Distribution Sotalol does not bind to plasma proteins.

Distribution occurs to a central (plasma) and to a peripheral compartment. Sotalol crosses the blood brain barrier poorly. Metabolism Sotalol is not metabolized and is not expected to inhibit or induce any CYP450 enzymes.

Excretion Excretion of sotalol is predominantly via the kidney in the unchanged form, and therefore, lower doses are necessary in conditions of renal impairment [ see Dosage and Administration (2.5) ]. The mean elimination half-life of sotalol is 12 hours. Dosing every 12 hours results in trough plasma concentrations which are approximately one-half of those at peak.

Specific Populations Pediatric: The combined analysis of a single-dose and a multiple-dose study with 59 children, aged between 3 days and 12 years, showed the pharmacokinetics of sotalol to be first order. A daily dose of 30 mg/m 2 of sotalol was administered in the single dose study and daily doses of 30, 90 and 210 mg/m 2 were administered every 8 hours in the multi-dose study. After rapid absorption with peak levels occurring on average between 2-3 hours following administration, sotalol was eliminated with a mean half-life of 9.5 hours.

Steady-state was reached after 1 to 2 days. The average peak to trough concentration ratio was 2. Body surface area was the most important covariate and more relevant than age for the pharmacokinetics of sotalol.

The smallest children (BSA <0.33 m 2 ) exhibited a greater drug exposure (+59%) than the larger children who showed a uniform drug concentration profile. The intersubject variation for oral clearance was 22%. Geriatric: Age does not significantly alter the pharmacokinetics of SOTYLIZE, but impaired renal function in geriatric patients can increase the terminal elimination half-life, resulting in increased drug accumulation.

Renal Impairment: Sotalol is mainly eliminated via the kidneys through glomerular filtration and to a small degree by tubular secretion. There is a direct relationship between renal function, as measured by serum creatinine or creatinine clearance, and the elimination rate of sotalol. The half-life of sotalol is prolonged (up to 69 hours) in anuric patients.

Adjust doses or dosing intervals based on creatinine clearance [see Dosage and Administration (2.5) ]. Hepatic Impairment: Patients with hepatic impairment show no alteration in clearance of sotalol. Drug-Drug Interactions Antacids: Administration of oral sotalol within 2 hours of antacids may result in a reduction in Cmax and AUC of 26% and 20%, respectively, and consequently in a 25% reduction in the bradycardic effect at rest.

Administration of the antacid two hours after oral sotalol has no effect on the pharmacokinetics or pharmacodynamics of sotalol. No pharmacokinetic interactions were observed with hydrochlorothiazide or warfarin.

12.2Pharmacodynamics Cardiac Electrophysiological Effects Sotalol hydrochloride prolongs the plateau phase of the cardiac action potential in the isolated myocyte, as well as in isolated tissue preparations of ventricular or atrial muscle (Class III activity). In intact animals it slows heart rate, decreases AV nodal conduction and increases the refractory periods of atrial and ventricular muscle and conduction tissue. In human, the Class II (beta-blockers) electrophysiological effects of sotalol are manifested by increased sinus cycle length (slowed heart rate), decreased AV nodal conduction and increased AV nodal refractoriness.

The Class III electrophysiological effects in man include prolongation of the atrial and ventricular monophasic action potentials, and effective refractory period prolongation of atrial muscle, ventricular muscle, and atrio-ventricular accessory pathways (where present) in both the anterograde and retrograde directions. With oral doses of 160 to 640 mg/day, the surface ECG shows dose-related mean increases of 40 to100 msec in QT and 10 to40 msec in QTc [see Warning and Precautions (5.1] ) . No significant alteration in QRS interval was observed.

In a small study (n=25) of patients with implanted defibrillators treated concurrently with sotalol, the average defibrillatory threshold was 6 joules (range 2 to15 joules) compared to a mean of 16 joules for a non-randomized comparative group primarily receiving amiodarone. Twenty-five children in an unblinded, multicenter trial with supraventricular (SVT) and/or ventricular (VT) tachyarrhythmias, aged between 3 days and 12 years (mostly neonates and infants), received an ascending titration regimen with daily doses of 30, 90 and 210 mg/m 2 with dosing every 8 hours for a total of 9 doses.

During steady-state, the respective average increases above baseline of the QT c interval, in msec (%), were 2, 14, and 29 msec at the 3 dose levels. The respective mean maximum increases above baseline of the QTc interval were 23, 36, and 55 msec at the 3 dose levels. The steady-state percent increases in the RR interval were 3, 9 and 12%.

The smallest children (BSA<0.33m 2 ) showed a tendency for larger Class III effects (∆QTc) and an increased frequency of prolongations of the QTc interval as compared with larger children (BSA≥0.33m 2 ). The beta-blocking effects also tended to be greater in the smaller children (BSA<0.33m 2 ). Both the Class III and beta-blocking effects of sotalol were linearly related with the plasma concentrations.

Hemodynamics In a study of systemic hemodynamic function measured invasively in 12 patients with a mean LV ejection fraction of 37% and ventricular tachycardia (9 sustained and 3 non-sustained), a median dose of 160 mg twice daily of sotalol produced a 28% reduction in heart rate and a 24% decrease in cardiac index at 2 hours post-dosing at steady-state. Concurrently, systemic vascular resistance and stroke volume showed non-significant increases of 25% and 8%, respectively. One patient was discontinued because of worsening congestive heart failure.

Pulmonary capillary wedge pressure increased significantly from 6.4 mmHg to 11.8 mmHg in the 11 patients who completed the study. Mean arterial pressure, mean pulmonary artery pressure and stroke work index did not significantly change. Exercise and isoproterenol induced tachycardia are antagonized by sotalol, and total peripheral resistance increases by a small amount.

In hypertensive patients, sotalol produces significant reductions in both systolic and diastolic blood pressures. Although sotalol is usually well-tolerated hemodynamically, deterioration in cardiac performance may occur in patients with marginal cardiac compensation [see Warnings and Precautions (5.3) ].

14 CLINICAL STUDIES

14.1Ventricular Arrhythmias In patients with life-threatening arrhythmias [sustained ventricular tachycardia/fibrillation (VT/VF)], sotalol was studied acutely [by suppression of programmed electrical stimulation (PES) induced VT and by suppression of Holter monitor evidence of sustained VT] and, in acute responders, chronically. In a double-blind, randomized comparison of sotalol and procainamide in 104 patients given intravenously (total of 2 mg/kg sotalol vs. 19 mg/kg of procainamide over 90 minutes), sotalol suppressed PES induction in 30% of patients vs.

20% for procainamide (p=0.2). In a randomized clinical trial (Electrophysiologic Study Versus Electrocardiographic Monitoring [ESVEM] Trial) in 486 patients comparing the choice of antiarrhythmic therapy by PES suppression vs. Holter monitor selection (in each case followed by treadmill exercise testing) in patients with a history of sustained VT/VF who were also inducible by PES, the effectiveness acutely and chronically of sotalol hydrochloride was compared with 6 other drugs (procainamide, quinidine, mexiletine, propafenone, imipramine, and pirmenol).

The Overall response, limited to first randomized drug, was 39% for sotalol and 30% for the pooled other drugs. Acute response rate for first drug randomized using suppression of PES induction was 36% for sotalol vs. a mean of 13% for the other drugs. Using the Holter monitoring endpoint (complete suppression of sustained VT, 90% suppression of NSVT, 80% suppression of PVC pairs, and at least 70% suppression of PVCs), sotalol yielded 41% response vs.

45% for the other drugs combined. Among responders placed on long-term therapy identified acutely as effective (by either PES or Holter), sotalol, when compared to the pool of other drugs, had the lowest two-year mortality (13% vs. 22%), the lowest two-year VT recurrence rate (30% vs.

60%), and the lowest withdrawal rate (38% vs. about 75 to 80%). The most commonly used doses of orally administered sotalol in this trial were 320 to480 mg/day (66% of patients), with 16% receiving 240 mg/day or less and 18% receiving 640 mg or more. It cannot be determined, however, in the absence of a controlled comparison of sotalol vs. no pharmacologic treatment (for example, in patients with implanted defibrillators) whether sotalol response causes improved survival or identifies a population with a good prognosis.

Sotalol has not been shown to enhance survival in patients with ventricular arrythmias.

14.2Supraventricular Arrhythmias Sotalol has been studied in patients with symptomatic AFIB/AFL in two principal studies, one in patients with primarily paroxysmal AFIB/AFL, the other in patients with primarily chronic AFIB. In one study, a U.S. multicenter, randomized, placebo-controlled, double-blind, dose-response trial of patients with symptomatic primarily paroxysmal AFIB/AFL, three fixed dose levels of sotalol (80 mg, 120 mg and 160 mg) twice daily and placebo were compared in 253 patients. In patients with reduced creatinine clearance (40 to 60 mL/min) the same doses were given once daily.

Patients were excluded for the following reasons: QT >450 msec; creatinine clearance <40 mL/min; intolerance to beta-blockers; bradycardia-tachycardia syndrome in the absence of an implanted pacemaker; AFIB/AFL was asymptomatic or was associated with syncope, embolic CVA or TIA; acute myocardial infarction within the previous 2 months; congestive heart failure; bronchial asthma or other contraindications to beta-blocker therapy; receiving potassium losing diuretics without potassium replacement or without concurrent use of ACE-inhibitors; uncorrected hypokalemia (serum potassium <3.5 mEq/L) or hypomagnesemia (serum magnesium <1.5 mEq/L); received chronic oral amiodarone therapy for >1 month within previous 12 weeks; congenital or acquired long QT syndromes; history of Torsade de Pointes with other antiarrhythmic agents which increase the duration of ventricular repolarization; si… [Excerpted — this section continues on DailyMed.]

13 NONCLINICAL TOXICOLOGY

13.1Carcinogenesis, Mutagenesis, Impairment of Fertility Calculations of safety margins are for the maximum recommended human dose (MRHD) of 640 mg/day of sotalol, administered for life-threatening ventricular arrhythmias in a 60-kg human. No evidence of carcinogenic potential was observed in rats during a 24-month study at 137 to275 mg/kg/day (approximately 30 times the maximum recommended human oral dose (MRHD) as mg/kg or 5 times the MRHD as mg/m 2 ) or in mice, during a 24-month study at 4141 to 7122 mg/kg/day (approximately 450 to 750 times the MRHD as mg/kg or 36 to 63 times the MRHD as mg/m 2 ).

Sotalol has not been evaluated in any specific assay of mutagenicity or clastogenicity.

13.2Animal Toxicology and/or Pharmacology No significant reduction in fertility occurred in rats at oral doses of 1000 mg/kg/day (approximately 94 times the MRHD as mg/kg or 15 times the MRHD as mg/m 2 ) prior to mating, except for a small reduction in the number of offspring per litter.