Sotylize

Dosage Forms And Strengths

Oral solution: 5 mg/mL, in 250 mL or 480 mL bottles.

Storage And Handling

SOTYLIZE (sotalol hydrochloride) is supplied as follows:

NDC 24338-530-25, 5 mg/mL: 250 mL bottle
NDC 24338-530-48, 5 mg/mL: 480 mL bottle

Storage

Store at 20°C to 25°C (68°F -77°F); excursions permitted between 15°C and 30°C (59°F-86°F).

Manufactured for: Atlanta, GA 30328. Manufactured by: Patheon Inc., Whitby Region Operations, 111 Consumers Drive, Whitby, ON L1N 5Z5 Canada. Distributed by: Arbor Pharmaceuticals, LLC, Atlanta, GA 30328. Issued: October/2014

Documented Life-Threatening Ventricular Arrhythmia

SOTYLIZE (sotalol hydrochloride) is indicated for the treatment of ventricular arrhythmias, such as sustained ventricular tachycardia, that in the judgment of the physician are life-threatening.

Upon initiation of SOTYLIZE, increasing doses, and prior to chronic outpatient use, evaluated response by a suitable method (e.g., PES or Holter monitoring) at steady-state blood levels of drug.

Limitation of Use

SOTYLIZE may not enhance survival in patients with ventricular arrhythmias. Because of the proarrhythmic effects of SOTYLIZE , including a 1.5 to 2% rate of Torsade de Pointes or new VT/VF in patients with either NSVT or supraventricular arrhythmias, its use in patients with less severe arrhythmias, even if the patients are symptomatic, is generally not recommended. Treatment of patients with asymptomatic ventricular premature contractions should be avoided.

Delay In Recurrence Of Atrial Fibrillation/Atrial Flutter

SOTYLIZE is indicated for the maintenance of normal sinus rhythm [delay in time to recurrence of atrial fibrillation/atrial flutter (AFIB/AFL)] in patients with symptomatic AFIB/AFL who are currently in sinus rhythm.

Limitation of Use

Because sotalol can cause life-threatening ventricular arrhythmias, reserve it for patients in whom AFIB/AFL is highly symptomatic. Patients with paroxysmal AFIB whose AFIB/AFL that is easily reversed (by Valsalva maneuver, for example) should usually not be given SOTYLIZE.

General Rules And Safety Measures Of Oral Sotalol Therapy

To minimize the risk of induced arrhythmia, patients initiated or re-initiated on sotalol should be hospitalized for at least 3 days or until steady-state drug levels are achieved, in a facility that can provide cardiac resuscitation and continuous electrocardiographic monitoring. Initiate oral sotalol therapy in the presence of personnel trained in the management of serious ventricular arrhythmias. Perform a baseline ECG to determine the QT interval and measure and normalize serum potassium and magnesium levels before initiating therapy with sotalol. Measure serum creatinine and calculate an estimated creatinine clearance in order to establish the appropriate dosing interval for sotalol.

Start sotalol therapy only if the baseline QTc interval is < 450 msec. During initiation and titration, monitor the QT interval after each dose. If the QTc interval prolongs to 500 msec or greater, reduce the dose, increase the interval between doses, or discontinue the drug.

Administer sotalol twice daily in patients with a creatinine clearance > 60 mL/min or once daily in patients with creatinine clearance between 40 and 60 mL/min. Sotalol is not recommended in patients with a creatinine clearance < 40 mL/min. The recommended initial oral dose of sotalol is 80 mg (once or twice daily) and is initiated and titrated as described below.

Patients to be discharged on SOTYLIZE therapy from an in-patient setting should have an adequate supply of SOTYLIZE, to allow uninterrupted therapy until the patient can fill a SOTYLIZE prescription.

Advise patients who miss a dose to take just the next dose at the usual time. 3

For patients discharged and taking compounded sotalol oral solution filled by the pharmacy, consider switching to SOTYLIZE while in an out-patient setting.

Table 1 shows the appropriate volume of SOTYLIZE solution for typical doses.

Table 1: SOTYLIZE Dose Volume

Ventricular Arrhythmia

The recommended initial dose of oral sotalol for the treatment of ventricular arrhythmia is 80 mg, once or twice daily based on creatinine clearance. The dose may be increased in increments of 80 mg per day every 3 days as needed, provided QTc < 500 msec. The usual therapeutic effect is observed with oral doses of 80 to 160 mg once or twice a day. Oral doses as high as 240-320 mg once or twice a day have been utilized in patients with refractory life-threatening arrhythmias.

Pediatrics

As in adults, initiate in the hospital after appropriate clinical assessment, gradually increase dose as required, and monitor QTc and heart rate.

For children aged 2 years and greater, with normal renal function, doses normalized for body surface area are appropriate for both initial and incremental dosing.

For initiation of treatment, 30 mg/m² three times a day (90 mg/m² total daily dose) is approximately equivalent to the initial 160 mg total daily dose for adults. Subsequent titration to a maximum of 60 mg/m² (approximately equivalent to the 360 mg total daily dose for adults) can then occur. Allow at least 36 hours between dose increments to attain steady-state plasma concentrations of sotalol in patients with normal renal function.

For children aged 2 years or younger, reduce the dose as shown in Figure 1.

Figure 1: Factor for dose adjustment by age

For a child with normal renal function aged 1 month, the initial starting dose would be (30 x 0.7) = 21 mg/m², administered three times daily. For a child aged about 1 week, the initial starting dose should be multiplied by 0.3; the starting dose would be (30 x 0.3) = 9 mg/m². Use similar calculations for dose titration.

Since the half-life of sotalol increases below about 2 years, time to steady-state will also increase. Thus, in neonates the time to steady-state may be a week or longer.

Symptomatic AFIB/AFL

The recommended initial dose of oral sotalol for the treatment of symptomatic AFIB/AFL is 80 mg, once or twice daily based on creatinine clearance. If that dose level at steady-state does not acceptably reduce the time to 4 recurrence of arrhythmia and is tolerated with QTc < 520 msec, increase the dose to 160 mg orally once or twice a day every three days. In the U.S. multicenter dose-response study, 120 mg orally once or twice a day was found to be the most effective dose in prolonging the time to ECG-documented symptomatic recurrence of AFIB/AFL.

Considerations In Renal Impairment

Sotalol elimination is predominantly via the kidney in the unchanged form. Use of sotalol in any age group with decreased renal function should be at lower doses or at increased intervals between doses. Monitoring of heart rate and QTc is most important and it will take much longer to reach steady-state with any dose and/or frequency of administration.

• Sinus bradycardia ( < 50 bpm during waking hours), sick sinus syndrome or second and third degree AV block unless a functioning pacemaker is present
• Congenital or acquired long QT syndromes, baseline QT interval > 450 ms
• Cardiogenic shock, uncontrolled heart failure
• Creatinine clearance < 40 mL/min
• Serum potassium < 4 meq/L
• Bronchial asthma or related bronchospastic conditions
• Known hypersensitivity to sotalol

WARNINGS

Included as part of the PRECAUTIONS section.

PRECAUTIONS

QT Prolongation And Proarrhythmia

Ventricular arrhythmias

SOTYLIZE can cause serious ventricular arrhythmias, primarily Torsade de Pointes (TdP) type ventricular tachycardia, a polymorphic ventricular tachycardia associated with QT interval prolongation. QT interval prolongation is directly related to the concentration of sotalol. Factors such as reduced creatinine clearance, gender (female) and larger doses increase the risk of TdP. The risk of TdP can be reduced by adjustment of the sotalol dose according to creatinine clearance and by monitoring the ECG for excessive increases in the QT interval..

Use with Drugs that Prolong QT Interval and Antiarrhythmic Agents

The use of SOTYLIZE in conjunction with other drugs that prolong the QT interval has not been studied and is not recommended. Such drugs include many antiarrhythmics, some phenothiazines, tricyclic antidepressants, certain oral macrolides and certain quinolone antibiotics. Class I or Class III antiarrhythmic agents should be withheld for at least three half-lives prior to dosing with sotalol. In clinical trials, sotalol was not administered to patients previously treated with oral amiodarone for > 1 month in the previous three months. Class Ia antiarrhythmic drugs, such as disopyramide, quinidine and procainamide and other Class III drugs (e.g., amiodarone) are not recommended as concomitant therapy with sotalol because of their potential to prolong refractoriness. There is only limited experience with the concomitant use of Class Ib or Ic antiarrhythmics.

Bradycardia/Heart Block

In studies of oral sotalol, the incidence of bradycardia (as determined by the investigators) in the supraventricular arrhythmia population treated with oral sotalol was 13%, and led to discontinuation in 2.4% of patients. Bradycardia itself increases the risk of Torsade de Pointes, so carefully monitor patients receiving concomitant digoxin.

Sick Sinus Syndrome

In general, SOTYLIZE is not recommended in patients with sick sinus syndrome associated with symptomatic arrhythmias, because it may cause sinus bradycardia, sinus pauses or sinus arrest. In patients with AFIB and sinus node dysfunction, sotalol increases the risk of Torsade de Pointes, especially after cardioversion. Sotalol augments bradycardia following cardioversion. Patients with AFIB/AFL associated with the sick sinus syndrome may be treated with sotalol if they have an implanted pacemaker for control of bradycardia symptoms.

Hypotension

Sotalol produces significant reductions in both systolic and diastolic blood pressures and may result in hypotension, including decompensated heart failure. Monitor hemodynamics in patients with marginal cardiac compensation.

Recent Acute MI

Oral sotalol has been used in a controlled trial following an acute myocardial infarction without evidence of increased mortality . Although specific studies of its use in treating atrial arrhythmias after infarction have not been conducted, the usual precautions regarding heart failure, avoidance of hypokalemia, bradycardia or prolonged QT interval apply. Experience in the use of sotalol to treat ventricular arrhythmias in the early phase of recovery from acute MI is limited. In the first 2 weeks post-MI careful dose titration is especially important, particularly in patients with markedly impaired ventricular function.

Abrupt Withdrawal

Hypersensitivity to catecholamines has been observed in patients withdrawn from beta-blocker therapy. Occasional cases of exacerbation of angina pectoris, arrhythmias and, in some cases, myocardial infarction have been reported after abrupt discontinuation of beta-blocker therapy. Therefore, when discontinuing chronically administered sotalol, particularly in patients with ischemic heart disease, carefully monitor the patient and consider the temporary use of an alternate beta-blocker if appropriate. If possible, the dosage of sotalol should be gradually reduced over a period of one to two weeks. If angina or acute coronary insufficiency develops, appropriate therapy should be instituted promptly. Patients should be warned against interruption or discontinuation of therapy without the physician's advice. Because coronary artery disease is common and may be unrecognized in patients receiving sotalol, abrupt discontinuation in patients with arrhythmias may unmask latent coronary insufficiency.

Electrolyte Disturbances

SOTYLIZE should not be used in patients with hypokalemia or hypomagnesemia prior to correction of imbalance, as these conditions increase the potential for Torsade de Pointes. Special attention should be given to electrolyte and acid-base balance in patients experiencing severe or prolonged diarrhea or patients receiving concomitant diuretic drugs.

Renal Impairment

Sotalol is eliminated principally 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.

Non-Allergic Bronchospasm

Patients with bronchospastic diseases should in general not receive beta-blockers. If SOTYLIZE is to be administered, use the smallest effective dose, to minimize inhibition of bronchodilation produced by endogenous or exogenous catecholamine stimulation of beta2 receptors.

Diabetes

Beta-blockade may mask some important premonitory signs of acute hypoglycemia (e.g., tachycardia) in patients with diabetes (especially labile diabetes) or with a history of episodes of spontaneous hypoglycemia.

Thyrotoxicosis

Beta-blockade may mask certain clinical signs (e.g., tachycardia) of hyperthyroidism. Avoid abrupt withdrawal of SOTYLIZE which might exacerbate symptoms of hyperthyroidism, including thyroid storm.

Anaphylaxis

While taking beta-blockers, patients with a history of anaphylactic reaction to a variety of allergens may have a more severe reaction on repeated challenge, either accidental, diagnostic, or therapeutic. Such patients may be unresponsive to the usual doses of epinephrine used to treat the allergic reaction.

Major Surgery

Chronically administered beta-blocking therapy should not be routinely withdrawn prior to major surgery; however, the impaired ability of the heart to respond to reflex adrenergic stimuli may augment the risks of general anesthesia and surgical procedures.

Patient Counseling Information

See FDA-approved PATIENT INFORMATION.

QT Prolongation and Proarrhythmia

Advise patients to contact their healthcare provider in the event of syncope, pre-syncopal symptoms and cardiac palpitations such as fainting, dizziness or fast heartbeats. Advise patients that their healthcare provider will monitor their electrolytes and ECG during treatment.

Diarrhea, Unusual Sweating, Vomiting, Reduced Appetite, Excessive Thirst

Advise patients to contact their healthcare provider in the event of conditions conducive to electrolyte changes such as severe diarrhea, unusual sweating, vomiting, less appetite than normal or excessive thirst.

Administration

Advise patients to not change the SOTYLIZE dose prescribed by their healthcare provider.

Advise patients that, to be sure doses are accurately measured, doses for children and infants should be measured using an appropriate measuring device such as an oral syringe. Advise them that a teaspoon or tablespoon should not be used to measure SOTYLIZE doses since doing so might lead to confusion and the wrong dose.  

Advise patients that they should not miss a dose, but if they do miss a dose they should not double the next dose to compensate for the missed dose; they should take the next dose at the regularly scheduled time.

Advise patients to not interrupt or discontinue SOTYLIZE without their physician's advice, that they should get their prescription for sotalol filled and refilled on time so they do not interrupt treatment.

Advise patients that they should not take SOTYLIZE if they also take another medicine that contains sotalol.

Advise patients that if overdose occurs or they take too much SOTYLIZE, take their SOTYLIZE medicine bottle with them and go to the nearest emergency room immediately. Overdoses can potentially cause life-threatening abnormal heart beats and possibly death.

Advise patients to contact their healthcare provider if they develop bradycardia.

Drug Interactions

Advise patients not to start taking other medications without first discussing new medications with their healthcare provider.

Antacids

Advise patients that they should avoid taking SOTYLIZE within 2 hours of taking antacids that contain aluminum oxide or magnesium hydroxide .

Nonclinical Toxicology

Carcinogenesis, Mutagenesis, Impairment Of Fertility

No evidence of carcinogenic potential was observed in rats during a 24-month study at 137-275 mg/kg/day (approximately 30 times the maximum recommended human oral dose (MRHD) as mg/kg or 5 times the MRHD as mg/m²) or in mice, during a 24-month study at 4141-7122 mg/kg/day (approximately 450750 times the MRHD as mg/kg or 36-63 times the MRHD as mg/m²).

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

No significant reduction in fertility occurred in rats at oral doses of 1000 mg/kg/day (approximately 100 times the MRHD as mg/kg or 9 times the MRHD as mg/m²) prior to mating, except for a small reduction in the number of offspring per litter.

Reproduction studies in rats and rabbits during organogenesis at 100 and 22 times the MRHD as mg/kg (9 and 7 times the MRHD as mg/m²), respectively, did not reveal any teratogenic potential associated with sotalol HCl. In rabbits, a high dose of sotalol HCl (160 mg/kg/day) at 16 times the MRHD as mg/kg (6 times the MRHD as mg/m²) produced a slight increase in fetal death likely due to maternal toxicity. Eight times the maximum dose (80 mg/kg/day or 3 times the MRHD as mg/m²) did not result in an increased incidence of fetal deaths. In rats, 1000 mg/kg/day sotalol HCl, 100 times the MRHD (18 times the MRHD as mg/m²), increased the number of early resorptions, while at 14 times the maximum dose (2.5 times the MRHD as mg/m²), no increase in early resorptions was noted. However, animal reproduction studies are not always predictive of human response.

Use In Specific Populations

Pregnancy

Pregnancy Category B

There are no adequate and well controlled studies in pregnant women. Sotalol crosses the placenta. In animal studies there was no increase in congenital anomalies, but an increase in early resorptions occurred at sotalol doses 18 times the maximum recommended human dose (MRHD, based on body surface area). Animal reproduction studies are not always predictive of human response.

Reproduction studies in rats and rabbits during organogenesis at sotalol doses 9 and 7 times the MRHD (based on body surface area), respectively, did not reveal any increase in congenital abnormalities. In rabbits, a sotalol dose 6 times the MRHD produced a slight increase in fetal death, but this was associated with maternal toxicity. This effect did not occur at a sotalol dose 3 times the MRHD. In rats, a sotalol dose 18 times the MRHD increased the number of early resorptions, while a dose of 2.5 times the MRHD produced no increase in early resorptions.

Nursing Mothers

Sotalol is excreted in the milk of laboratory animals and has been reported to be present in human milk. Discontinue nursing or SOTYLIZE.

Pediatric Use

The safety and effectiveness of sotalol in children have not been established. However, the Class III electrophysiologic and beta-blocking effects, the pharmacokinetics, and the relationship between the effects (QTc interval and resting heart rate) and drug concentrations have been evaluated in children aged between 3 days and 12 years old.

Geriatric Use

Impaired renal function in geriatric patients can increase the terminal elimination half-life, resulting in increased drug accumulation.

Patients With Renal Impairment

Sotalol is eliminated principally 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 dosing interval (time between divided doses) of sotalol should be modified when creatinine clearance is lower than 60 mL/min. Sotalol is contraindicated when creatinine clearance is less than 40 mL/min.

SIDE EFFECTS

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

Adults

Adverse reactions that are clearly related to sotalol are those which are typical of its Class II (beta-blocking) and Class III (cardiac action potential duration prolongation) effects. The common documented beta-blocking adverse reactions (bradycardia, dyspnea, and fatigue) and Class III effects (QT interval prolongation) are dose related.

Serious Adverse Reactions

SOTYLIZE can cause serious ventricular arrhythmias, primarily Torsade de Pointes (TdP) type ventricular tachycardia, a polymorphic ventricular tachycardia associated with QT interval prolongation. QT interval prolongation is directly related to the plasma level of sotalol. Factors such as reduced creatinine clearance, gender (female) and larger doses increase the risk of TdP.

Proarrhythmia in Atrial Fibrillation Patients

In eight controlled trials of patients with AFIB/AFL and other supraventricular arrhythmias (N=659) there were four cases of TdP reported (0.6%) during the controlled phase of treatment with oral sotalol.

Prolongation of the QT interval is dose related, increasing from baseline an average of 25, 40, and 50 msec in the 80, 120, and 160 mg groups, respectively, in the oral dose-response study.

Proarrhythmia in Ventricular Arrhythmia Patients

In patients with a history of sustained ventricular tachycardia, the incidence of Torsade de Pointes during oral sotalol treatment was 4% and worsened VT was about 1%; in patients with other less serious ventricular arrhythmias the incidence of Torsade de Pointes was 1% and new or worsened VT was about 0.7%. Additionally, in approximately 1% of patients, deaths were considered possibly drug related; such cases, although difficult to evaluate, may have been associated with proarrhythmic events. Torsade de Pointes arrhythmias in patients with VT/VF were dose related, as was the prolongation of QT (QTc) interval, as shown in Table 2 below.

Table 2: Percent Incidence of Torsade de Pointes and Mean QTc Interval by Dose For Patients With Sustained VT/VF

Table 3 below relates the incidence of Torsade de Pointes to on-therapy QTc and change in QTc from baseline. It should be noted, however, that the highest on-therapy QTc was in many cases the one obtained at the time of the Torsade de Pointes event, so that the table overstates the predictive value of a high QTc.

Table 3: Relationship Between QTc Interval Prolongation and Torsade de Pointes

In addition to dose and presence of sustained VT, other risk factors for Torsade de Pointes were gender (females had a higher incidence), excessive prolongation of the QTc interval and history of cardiomegaly or congestive heart failure. Patients with sustained ventricular tachycardia and a history of congestive heart failure appear to have the highest risk for serious proarrhythmia (7%). Of the ventricular arrhythmia patients experiencing Torsade de Pointes, approximately two-thirds spontaneously reverted to their baseline rhythm. The others were either converted electrically (D/C cardioversion or overdrive pacing) or treated with other drugs. It is not possible to determine whether some sudden deaths represented episodes of Torsade de Pointes, but in some instances sudden death did follow a documented episode of Torsade de Pointes. Although sotalol therapy was discontinued in most patients experiencing Torsade de Pointes, 17% were continued on a lower dose.

Other Adverse Reactions

In a pooled clinical trial population consisting of four placebo-controlled studies with 275 patients with AFIB/AFL treated with 160-320 mg of oral sotalol, the following adverse events were reported at least 2% more frequently in the 160-240 mg sotalol treated patients than in placebo patients (see Table 4). The data are presented by incidence of events in the oral sotalol and placebo groups by body system and daily dose.

Table 4: Incidence (%) of Common Adverse Reactions ( ≥ 2% more frequent in patients treated in the 160-240 mg group than on placebo) in Four Placebo-Controlled Studies of Patients with AFIB/AFL Treated with Oral Sotalol

In AFIB/AFL patients, discontinuation because of unacceptable adverse reactions was necessary in 17% of the patients, and occurred in 10% of patients less than two weeks after starting treatment. The most common adverse reactions leading to discontinuation of sotalol were: fatigue 4.6%, bradycardia 2.4%, proarrhythmia 2.2%, dyspnea 2%, and QT interval prolongation 1.4%.

In clinical trials involving 1292 patients with sustained VT/VF, the common adverse events were similar to those described for the AFIB/AFL population.

One case of peripheral neuropathy which resolved on discontinuation of sotalol and recurred when the patient was rechallenged with the drug was reported in an early dose tolerance study. Elevated blood glucose levels and increased insulin requirements can occur in diabetic patients.

Pediatric Patients

In an unblinded multicenter trial of 25 patients with SVT and/or VT receiving daily doses of 30, 90 and 210 mg/m² with dosing every 8 hours for a total of 9 doses, no Torsade de Pointes or other serious new arrhythmias were observed. One (1) patient, receiving 30 mg/m² daily, was discontinued because of increased frequency of sinus pauses/bradycardia. Additional cardiovascular adverse events were seen at the 90 and 210 mg/m² daily dose levels. They included QT prolongations (2 patients), sinus pauses/bradycardia (1 patient), increased severity of atrial flutter and reported chest pain (1 patient). Values for QTc ≥ 525 msec were seen in 2 patients at the 210 mg/m² daily dose level. Serious adverse events including death, Torsade de Pointes, other proarrhythmias, high-degree A-V blocks and bradycardia have been reported in infants and/or children.

Postmarketing Experience

The following adverse reactions have been identified during post-approval use of sotalol. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to estimate reliably their frequency or establish a causal relationship to drug exposure.

Postmarketing experience with sotalol shows an adverse event profile similar to that described above from clinical trials. Voluntary reports since introduction include rare reports (less than one report per 10,000 patients) of: emotional liability, slightly clouded sensorium, incoordination, vertigo, paralysis, thrombocytopenia, eosinophilia, leukopenia, photosensitivity reaction, fever, pulmonary edema, hyperlipidemia, myalgia, pruritus, alopecia.

DRUG INTERACTIONS

Digoxin

Proarrhythmic events were more common in sotalol treated patients also receiving digoxin; it is not clear whether this represents an interaction or is related to the presence of heart failure, a known risk factor for proarrhythmia, in the patients receiving digoxin.

Calcium-Blocking Drugs

Sotalol and calcium blocking drugs can be expected to have additive effects on atrioventricular conduction, ventricular function, and blood pressure.

Catecholamine-Depleting Agents

Concomitant use of catecholamine-depleting drugs, such as reserpine and guanethidine, with a beta-blocker may produce an excessive reduction of resting sympathetic nervous tone. Monitor such patients for hypotension and marked bradycardia which may produce syncope.

Insulin And Oral Antidiabetic Agents

Hyperglycemia may occur, and the dosage of insulin or antidiabetic drugs may require adjustment. Symptoms of hypoglycemia may be masked.

Beta-2-Receptor Stimulants

Beta-agonists such as albuterol, terbutaline and isoproterenol may have to be administered in increased dosages when used concomitantly with sotalol.

Clonidine

Beta-blocking drugs may potentiate the rebound hypertension sometimes observed after discontinuation of clonidine.

Drugs That Prolong QT Interval And Antiarrhythmic Agents

Sotalol has not been studied with other drugs that prolong the QT interval such as antiarrhythmics, some phenothiazines, tricyclic antidepressants, certain oral macrolides and certain quinolone antibiotics. Class I or Class III antiarrhythmic agents should be withheld for at least three half-lives prior to dosing with sotalol. In clinical trials, sotalol was not administered to patients previously treated with oral amiodarone for > 1 month in the previous three months. Class Ia antiarrhythmic drugs such as disopyramide, quinidine and procainamide and other Class III drugs (e.g., amiodarone) are not recommended as concomitant therapy with sotalol because of their potential to prolong refractoriness. There is only limited experience with the concomitant use of Class Ib or Ic antiarrhythmics.

Antacids

Administration of oral sotalol within 2 hours of antacids containing aluminum oxide and magnesium hydroxide should be avoided because it 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.

Pregnancy Category B

There are no adequate and well controlled studies in pregnant women. Sotalol crosses the placenta. In animal studies there was no increase in congenital anomalies, but an increase in early resorptions occurred at sotalol doses 18 times the maximum recommended human dose (MRHD, based on body surface area). Animal reproduction studies are not always predictive of human response.

Reproduction studies in rats and rabbits during organogenesis at sotalol doses 9 and 7 times the MRHD (based on body surface area), respectively, did not reveal any increase in congenital abnormalities. In rabbits, a sotalol dose 6 times the MRHD produced a slight increase in fetal death, but this was associated with maternal toxicity. This effect did not occur at a sotalol dose 3 times the MRHD. In rats, a sotalol dose 18 times the MRHD increased the number of early resorptions, while a dose of 2.5 times the MRHD produced no increase in early resorptions.

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

Adults

Adverse reactions that are clearly related to sotalol are those which are typical of its Class II (beta-blocking) and Class III (cardiac action potential duration prolongation) effects. The common documented beta-blocking adverse reactions (bradycardia, dyspnea, and fatigue) and Class III effects (QT interval prolongation) are dose related.

Serious Adverse Reactions

SOTYLIZE can cause serious ventricular arrhythmias, primarily Torsade de Pointes (TdP) type ventricular tachycardia, a polymorphic ventricular tachycardia associated with QT interval prolongation. QT interval prolongation is directly related to the plasma level of sotalol. Factors such as reduced creatinine clearance, gender (female) and larger doses increase the risk of TdP.

Proarrhythmia in Atrial Fibrillation Patients

In eight controlled trials of patients with AFIB/AFL and other supraventricular arrhythmias (N=659) there were four cases of TdP reported (0.6%) during the controlled phase of treatment with oral sotalol.

Prolongation of the QT interval is dose related, increasing from baseline an average of 25, 40, and 50 msec in the 80, 120, and 160 mg groups, respectively, in the oral dose-response study.

Proarrhythmia in Ventricular Arrhythmia Patients

In patients with a history of sustained ventricular tachycardia, the incidence of Torsade de Pointes during oral sotalol treatment was 4% and worsened VT was about 1%; in patients with other less serious ventricular arrhythmias the incidence of Torsade de Pointes was 1% and new or worsened VT was about 0.7%. Additionally, in approximately 1% of patients, deaths were considered possibly drug related; such cases, although difficult to evaluate, may have been associated with proarrhythmic events. Torsade de Pointes arrhythmias in patients with VT/VF were dose related, as was the prolongation of QT (QTc) interval, as shown in Table 2 below.

Table 2: Percent Incidence of Torsade de Pointes and Mean QTc Interval by Dose For Patients With Sustained VT/VF

Table 3 below relates the incidence of Torsade de Pointes to on-therapy QTc and change in QTc from baseline. It should be noted, however, that the highest on-therapy QTc was in many cases the one obtained at the time of the Torsade de Pointes event, so that the table overstates the predictive value of a high QTc.

Table 3: Relationship Between QTc Interval Prolongation and Torsade de Pointes

In addition to dose and presence of sustained VT, other risk factors for Torsade de Pointes were gender (females had a higher incidence), excessive prolongation of the QTc interval and history of cardiomegaly or congestive heart failure. Patients with sustained ventricular tachycardia and a history of congestive heart failure appear to have the highest risk for serious proarrhythmia (7%). Of the ventricular arrhythmia patients experiencing Torsade de Pointes, approximately two-thirds spontaneously reverted to their baseline rhythm. The others were either converted electrically (D/C cardioversion or overdrive pacing) or treated with other drugs. It is not possible to determine whether some sudden deaths represented episodes of Torsade de Pointes, but in some instances sudden death did follow a documented episode of Torsade de Pointes. Although sotalol therapy was discontinued in most patients experiencing Torsade de Pointes, 17% were continued on a lower dose.

Other Adverse Reactions

In a pooled clinical trial population consisting of four placebo-controlled studies with 275 patients with AFIB/AFL treated with 160-320 mg of oral sotalol, the following adverse events were reported at least 2% more frequently in the 160-240 mg sotalol treated patients than in placebo patients (see Table 4). The data are presented by incidence of events in the oral sotalol and placebo groups by body system and daily dose.

Table 4: Incidence (%) of Common Adverse Reactions ( ≥ 2% more frequent in patients treated in the 160-240 mg group than on placebo) in Four Placebo-Controlled Studies of Patients with AFIB/AFL Treated with Oral Sotalol

In AFIB/AFL patients, discontinuation because of unacceptable adverse reactions was necessary in 17% of the patients, and occurred in 10% of patients less than two weeks after starting treatment. The most common adverse reactions leading to discontinuation of sotalol were: fatigue 4.6%, bradycardia 2.4%, proarrhythmia 2.2%, dyspnea 2%, and QT interval prolongation 1.4%.

In clinical trials involving 1292 patients with sustained VT/VF, the common adverse events were similar to those described for the AFIB/AFL population.

One case of peripheral neuropathy which resolved on discontinuation of sotalol and recurred when the patient was rechallenged with the drug was reported in an early dose tolerance study. Elevated blood glucose levels and increased insulin requirements can occur in diabetic patients.

Pediatric Patients

In an unblinded multicenter trial of 25 patients with SVT and/or VT receiving daily doses of 30, 90 and 210 mg/m² with dosing every 8 hours for a total of 9 doses, no Torsade de Pointes or other serious new arrhythmias were observed. One (1) patient, receiving 30 mg/m² daily, was discontinued because of increased frequency of sinus pauses/bradycardia. Additional cardiovascular adverse events were seen at the 90 and 210 mg/m² daily dose levels. They included QT prolongations (2 patients), sinus pauses/bradycardia (1 patient), increased severity of atrial flutter and reported chest pain (1 patient). Values for QTc ≥ 525 msec were seen in 2 patients at the 210 mg/m² daily dose level. Serious adverse events including death, Torsade de Pointes, other proarrhythmias, high-degree A-V blocks and bradycardia have been reported in infants and/or children.

Postmarketing Experience

The following adverse reactions have been identified during post-approval use of sotalol. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to estimate reliably their frequency or establish a causal relationship to drug exposure.

Postmarketing experience with sotalol shows an adverse event profile similar to that described above from clinical trials. Voluntary reports since introduction include rare reports (less than one report per 10,000 patients) of: emotional liability, slightly clouded sensorium, incoordination, vertigo, paralysis, thrombocytopenia, eosinophilia, leukopenia, photosensitivity reaction, fever, pulmonary edema, hyperlipidemia, myalgia, pruritus, alopecia.

Intentional or accidental overdosage with sotalol has resulted in death.

Symptoms and Treatment of Overdosage

The most common signs to be expected are bradycardia, congestive heart failure, hypotension, bronchospasm and hypoglycemia. In cases of massive intentional overdosage (2-16 grams) of sotalol the following clinical findings were seen: hypotension, bradycardia, cardiac asystole, prolongation of QT interval, Torsade de Pointes, ventricular tachycardia, and premature ventricular complexes. If overdosage occurs, therapy with sotalol should be discontinued and the patient observed closely. Because of the lack of protein binding, hemodialysis is useful for reducing sotalol plasma concentrations. Patients should be carefully observed until QT intervals are normalized and the heart rate returns to levels > 50 bpm. The occurrence of hypotension following an overdose may be associated with an initial slow drug elimination phase (half-life of 30 hours) thought to be due to a temporary reduction of renal function caused by the hypotension. In addition, if required, the following therapeutic measures are suggested:

Bradycardia or Cardiac Asystole: Atropine, another anticholinergic drug, a beta-adrenergic agonist or transvenous cardiac pacing.

Heart Block: (second and third degree) transvenous cardiac pacemaker.

Hypotension: (depending on associated factors) epinephrine rather than isoproterenol or norepinephrine may be useful.

Bronchospasm: Aminophylline or aerosol beta-2-receptor stimulant.

Torsade de Pointes: DC cardioversion, magnesium sulfate, potassium replacement. Once Torsade de Pointes is terminated, transvenous cardiac pacing or an isoproterenol infusion to increase heart rate can be employed.

Electrophysiology

Sotalol 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 man, the Class II (beta-blockade) 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 40-100 msec in QT and 10-40 msec in QTc. In a study of patients with atrial fibrillation/flutter (AFIB/AFL) receiving three different oral doses of sotalol given q12h (or q24h in patients with a reduced creatinine clearance), mean increases in QT intervals measured from 12-lead ECGs of 25 msec, 40 msec and 54 msec were found in the 80 mg, 120 mg, and 160 mg dose groups, respectively. 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 2-15 joules) compared to a mean of 16 joules for a non-randomized comparative group primarily receiving amiodarone.

In a dose-response trial comparing three dose levels of sotalol, 80 mg, 120 mg, and 160 mg with placebo given every 12 hours (or every 24 hours in patients with a reduced renal creatinine clearance) for the prevention of recurrence of symptomatic atrial fibrillation (AFIB)/flutter (AFL), the mean ventricular rate during recurrence of AFIB/AFL was 125, 107, 110 and 99 beats/min in the placebo, 80 mg, 120 mg and 160 mg dose groups, respectively (p < 0.017 for each sotalol dose group versus placebo). In another placebo controlled trial in which sotalol was titrated to a dose between 160 and 320 mg/day in patients with chronic AFIB, the mean ventricular rate during recurrence of AFIB was 107 and 84 beats/min in the placebo and sotalol groups, respectively (p < 0.001).

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/m² with dosing every 8 hours for a total of 9 doses. During steady-state, the respective average increases above baseline of the QTc interval, in msec (%), were 2(+1%), 14(+4%) and 29(+7%) msec at the 3 dose levels. The respective mean maximum increases above baseline of the QTc interval, in msec (%), were 23(+6%), 36(+9%) and 55(+14%) msec at the 3 dose levels. The steady-state percent increases in the RR interval were 3, 9 and 12%. The smallest children (BSA < 0.33m²) showed a tendency for larger Class III effects (ΔQTc) and an increased frequency of prolongations of the QTc interval as compared with the larger children (BSA ≥ 0.33m²). The beta-blocking effects also tended to be greater in the smaller children (BSA < 0.33m²). 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. Pulmonary capillary wedge pressure increased significantly from 6.4 mmHg to 11.8 mmHg in the 11 patients who completed the study. One patient was discontinued because of worsening congestive heart failure. 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, in patients with marginal cardiac compensation, deterioration in cardiac performance may occur.

In healthy subjects, the oral bioavailability of sotalol is 90-100%. After oral administration, peak plasma concentrations are reached in 2.5 to 4 hours, and steady-state plasma concentrations are attained within 2-3 days (i.e., after 5-6 doses when administered twice daily). Over the oral dosage range 160-640 mg/day sotalol displays dose proportionality with respect to plasma concentrations. Distribution occurs to a central (plasma) and to a peripheral compartment, with a mean elimination half-life of 12 hours. Dosing every 12 hours results in trough plasma concentrations, which are approximately one-half of those at peak.

Sotalol does not bind to plasma proteins and is not metabolized. Sotalol shows very little intersubject variability in plasma levels. The pharmacokinetics of the d and l enantiomers of sotalol are essentially identical. Sotalol crosses the blood brain barrier poorly. Excretion is predominantly via the kidney in the unchanged form, and therefore lower doses are necessary in conditions of renal impairment. Age per se does not significantly alter the pharmacokinetics of sotalol, but impaired renal function in geriatric patients can increase the terminal elimination half-life, resulting in increased drug accumulation. The absorption of sotalol was reduced by approximately 20% compared to fasting when it was administered with a standard meal. Since sotalol is not subject to first-pass metabolism, patients with hepatic impairment show no alteration in clearance of sotalol.

The combined analysis of two unblinded, multicenter trials (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/m² of sotalol was administered in the single dose study and daily doses of 30, 90 and 210 mg/m² 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 1-2 days. The average peak to trough concentration ratio was 2. BSA was the most important covariate and more relevant than age for the pharmacokinetics of sotalol. The smallest children (BSA < 0.33m²) 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%.