To minimize the risk of induced arrhythmia, patients initiated or reinitiated on sotalol hydrochloride tablets should be placed for a minimum of three days (on their maintenance dose) in a facility that can provide cardiac resuscitation and continuous electrocardiographic monitoring. Creatinine clearance should be calculated prior to dosing. For detailed instructions regarding dose selection and special cautions for people with renal impairment, see DOSAGE AND ADMINISTRATION. Sotalol is also 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 and is marketed under the brand name Betapace AF®. Sotalol hydrochloride tablets, USP are not approved for the AFIB/AFL indication and should not be substituted for Betapace AF because only Betapace AF is distributed with a patient package insert that is appropriate for patients with AFIB/AFL.
Sotalol hydrochloride tablets, USP are an antiarrhythmic drug with Class II (beta-adrenoreceptor blocking) and Class III (cardiac action potential duration prolongation) properties. It is supplied as a white to off-white, capsule-shaped, scored tablet for oral administration. Sotalol hydrochloride is a white, crystalline solid with a molecular weight of 308.8. It is hydrophilic, soluble in water, propylene glycol and ethanol, but is only slightly soluble in chloroform. Chemically, sotalol hydrochloride is d,l-N-[4-[1-hydroxy-2-[(1-methylethyl) amino]ethyl]phenyl]methane-sulfonamide monohydrochloride. The molecular formula is C12H20N203S•HCl and is represented by the following structural formula:
Each tablet, for oral administration, contains 80 mg, 120 mg, 160 mg or 240 mg of sotalol hydrochloride. In addition, each tablet also contains the following inactive ingredients: magnesium stearate and microcrystalline cellulose.
Sotalol hydrochloride tablets, USP are indicated for the treatment of documented ventricular arrhythmias, such as sustained ventricular tachycardia, that in the judgment of the physician are life-threatening. Because of the proarrhythmic effects of sotalol hydrochloride tablets, USP (see WARNINGS), 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.
Initiation of sotalol hydrochloride treatment or increasing doses, as with other antiarrhythmic agents used to treat life-threatening arrhythmias, should be carried out in the hospital. The response to treatment should then be evaluated by a suitable method (e.g., PES or Holter monitoring) prior to continuing the patient on chronic therapy. Various approaches have been used to determine the response to antiarrhythmic therapy, including sotalol hydrochloride tablets, USP.
In the ESVEM Trial, response by Holter monitoring was tentatively defined as 100% suppression of ventricular tachycardia, 90% suppression of nonsustained VT, 80% suppression of paired VPCs, and 75% suppression of total VPCs in patients who had at least 10 VPCs/hour at baseline; this tentative response was confirmed if VT lasting 5 or more beats was not observed during treadmill exercise testing using a standard Bruce protocol. The PES protocol utilized a maximum of three extrastimuli at three pacing cycle lengths and two right ventricular pacing sites. Response by PES was defined as prevention of induction of the following: 1) monomorphic VT lasting over 15 seconds; 2) non-sustained polymorphic VT containing more than 15 beats of monomorphic VT in patients with a history of monomorphic VT; 3) polymorphic VT or VF greater than 15 beats in patients with VF or a history of aborted sudden death without monomorphic VT; and 4) two episodes of polymorphic VT or VF of greater than 15 beats in a patient presenting with monomorphic VT. Sustained VT or NSVT producing hypotension during the final treadmill test was considered a drug failure.
In a multicenter open-label long-term study of sotalol in patients with life-threatening ventricular arrhythmias which had proven refractory to other antiarrhythmic medications, response by Holter monitoring was defined as in ESVEM. Response by PES was defined as non-inducibility of sustained VT by at least double extrastimuli delivered at a pacing cycle length of 400 msec. Overall survival and arrhythmia recurrence rates in this study were similar to those seen in ESVEM, although there was no comparative group to allow a definitive assessment of outcome.
Antiarrhythmic drugs have not been shown to enhance survival in patients with ventricular arrhythmias.
Sotalol is also 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 and is marketed under the brand name Betapace AF (sotalol hydrochloride, tablets, USP). Sotalol hydrochloride tablets, USP is not approved for the AFIB/AFL indication and should not be substituted for Betapace AF because only Betapace AF is distributed with a patient package insert that is appropriate for patients with AFIB/AFL.
DOSAGE AND ADMINISTRATION
As with other antiarrhythmic agents, sotalol hydrochloride tablets, USP should be initiated and doses increased in a hospital with facilities for cardiac rhythm monitoring and assessment (see INDICATIONS AND USAGE). Sotalol hydrochloride tablets, USP should be administered only after appropriate clinical assessment (see INDICATIONS AND USAGE), and the dosage of sotalol hydrochloride tablets, USP must be individualized for each patient on the basis of therapeutic response and tolerance. Proarrhythmic events can occur not only at initiation of therapy, but also with each upward dosage adjustment.
Dosage of sotalol hydrochloride tablets, USP should be adjusted gradually, allowing 3 days between dosing increments in order to attain steady-state plasma concentrations, and to allow monitoring of QT intervals. Graded dose adjustment will help prevent the usage of doses which are higher than necessary to control the arrhythmia. The recommended initial dose is 80 mg twice daily. This dose may be increased, if necessary, after appropriate evaluation to 240 or 320 mg/day (120 to 160 mg twice daily). In most patients, a therapeutic response is obtained at a total daily dose of 160 to 320 mg/day, given in two or three divided doses. Some patients with life-threatening refractory ventricular arrhythmias may require doses as high as 480 to 640 mg/day; however, these doses should only be prescribed when the potential benefit outweighs the increased risk of adverse events, in particular proarrhythmia. Because of the long terminal elimination half-life of sotalol, dosing on more than a BID regimen is usually not necessary.
As in adults the following precautionary measures should be considered when initiating sotalol treatment in children: initiation of treatment in the hospital after appropriate clinical assessment; individualized regimen as appropriate; gradual increase of doses if required; careful assessment of therapeutic response and tolerability; and frequent monitoring of the QTc interval and heart rate.
For Children Aged About 2 Years and Greater
For children aged about 2 years and greater, with normal renal function, doses normalized for body surface area are appropriate for both initial and incremental dosing. Since the Class III potency in children (see CLINICAL PHARMACOLOGY) is not very different from that in adults, reaching plasma concentrations that occur within the adult dose range is an appropriate guide. From pediatric pharmacokinetic data the following is recommended.
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. Titration should be guided by clinical response, heart rate and QTc, with increased dosing being preferably carried out in-hospital. At least 36 hours should be allowed between dose increments to attain steadystate plasma concentrations of sotalol in patients with age-adjusted normal renal function.
For Children Aged About 2 Years or Younger
For children aged about 2 years or younger, the above pediatric dosage should be reduced by a factor that depends heavily upon age, as shown in the following graph, age plotted on a logarithmic scale in months.
For a child aged 20 months, the dosing suggested for children with normal renal function aged 2 years or greater should be multiplied by about 0.97; the initial starting dose would be (30 X 0.97)=29.1 mg/m², administered three times daily. For a child aged 1 month, the starting dose should be multiplied by 0.68; the initial starting dose would be (30 X 0.68)=20 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. Similar calculations should be made for increased doses as titration proceeds. Since the half-life of sotalol decreases with decreasing age (below about 2 years), time to steady-state will also increase. Thus, in neonates the time to steady-state may be as long as a week or longer.
In all children, individualization of dosage is required. As in adults Betapace (sotalol hydrochloride) should be used with particular caution in children if the QTc is greater than 500 msec on therapy, and serious consideration should be given to reducing the dose or discontinuing therapy when QTc exceeds 550 msec.
Dosage In Renal Impairment
Because sotalol is excreted predominantly in urine and its terminal elimination half-life is prolonged in conditions of renal impairment, the dosing interval (time between divided doses) of sotalol should be modified (when creatinine clearance is lower than 60 mL/min) according to the following table.
|Creatinine Clearance mL/min||Dosinga Interval (hours)|
|< 10||Dose should be individualized|
|aThe initial dose of 80 mg and subsequent doses should be administered at these intervals. See following paragraph for dosage escalations.|
Since the terminal elimination half-life of sotalol hydrochloride is increased in patients with renal impairment, a longer duration of dosing is required to reach steady-state. Dose escalations in renal impairment should be done after administration of at least 5 to 6 doses at appropriate intervals (see table above). Extreme caution should be exercised in the use of sotalol in patients with renal failure undergoing hemodialysis. The half-life of sotalol is prolonged (up to 69 hours) in anuric patients. Sotalol, however, can be partly removed by dialysis with subsequent partial rebound in concentrations when dialysis is completed. Both safety (heart rate, QT interval) and efficacy (arrhythmia control) must be closely monitored.
The use of sotalol hydrochloride in children with renal impairment has not been investigated. 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 more important and it will take much longer to reach steady-state with any dose and/or frequency of administration.
Transfer To Sotalol Hydrochloride Tablets, USP
Before starting sotalol hydrochloride tablets, USP, previous antiarrhythmic therapy should generally be withdrawn under careful monitoring for a minimum of 2 to 3 plasma half-lives if the patient's clinical condition permits (see DRUG INTERACTIONS). Treatment has been initiated in some patients receiving I.V. lidocaine without ill effect. After discontinuation of amiodarone, sotalol hydrochloride tablets, USP should not be initiated until the QT interval is normalized (see WARNINGS).
Preparation Of Extemporaneous Oral Solution
Information relating to the preparation of an extemporaneous oral solution of sotalol is approved for Berlex Laboratories' sotalol hydrochloride tablets. However, due to Berlex's marketing exclusivity rights, this drug product is not labeled with that information.
Transfer To Betapace AF From Sotalol Hydrochloride Tablets, USP
Patients with a history of symptomatic AFIB/AFL who are currently receiving sotalol hydrochloride tablets, USP for the maintenance of normal sinus rhythm should be transferred to Betapace AF because of the significant differences in labeling (i.e., patient package insert for Betapace AF, dosing administration, and safety information).
Sotalol Hydrochloride Tablets, USP 80 mg are available for oral administration as white to off-white capsule shaped, scored tablets, imprinted “APO” on one side and “SO” bisect “80” on the other side; supplied in bottles of 100 (NDC 60505-0080-0) and bottles of 1000 (NDC 60505-0080-1).
Sotalol Hydrochloride Tablets, USP 120 mg are available for oral administration as white to off-white capsule shaped, scored tablets, imprinted “APO” on one side and “SOT” bisect “120” on the other side; supplied in bottles of 100 (NDC 60505-0159-0) and bottles of 1000 (NDC 60505-0159-1).
Sotalol Hydrochloride Tablets, USP 160 mg are available for oral administration as white to off-white capsule shaped, scored tablets, imprinted “APO” on one side and “SOT” bisect “160” on the other side; supplied in bottles of 100 (NDC 60505-0081-0) and bottles of 1000 (NDC 60505-0081-1).
Sotalol Hydrochloride Tablets, USP 240 mg are available for oral administration as white to off-white capsule shaped, scored tablets, imprinted “APO” on one side and “SOT” bisect “240” on the other side; supplied in bottles of 100 (NDC 60505-0082-0) and bottles of 1000 (NDC 60505-0082-1).
Store at 20° to 25°C (68° to 77°F); excursions permitted from 15° to 30°C (59° to 86°F) [see USP Controlled Room Temperature].
Dispense in tight, light-resistant container [see USP].
Manufactured by : Apotex Inc. Toronto, Ontario, Canada M9L 1T9. Manufactured for : Apotex Corp. Weston, Florida. 33326. Revised: April 2015
During premarketing trials, 3186 patients with cardiac arrhythmias (1363 with sustained ventricular tachycardia) received oral sotalol, of whom 2451 received the drug for at least two weeks. The most important adverse effects are Torsade de Pointes and other serious new ventricular arrhythmias (see WARNINGS), occurring at rates of almost 4% and 1%, respectively, in the VT/VF population. Overall, discontinuation because of unacceptable side-effects was necessary in 17% of all patients in clinical trials, and in 13% of patients treated for at least two weeks. The most common adverse reactions leading to discontinuation of sotalol are as follows: fatigue 4%, bradycardia (less than 50 bpm) 3%, dyspnea 3%, proarrhythmia 3%, asthenia 2%, and dizziness 2%.
Occasional reports of elevated serum liver enzymes have occurred with sotalol therapy but no cause and effect relationship has been established. 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.
The following table lists as a function of dosage the most common (incidence of 2% or greater) adverse events, regardless of relationship to therapy and the percent of patients discontinued due to the event, as collected from clinical trials involving 1292 patients with sustained VT/VF.
Incidence (%) of Adverse Events and Discontinuations DAILY
|Incidence (%) of Adverse Events and Discontinuations
|Body System||160 mg
|% Patients Discontinued
|Body as a whole|
|localized pain||1||1||2||2||2||3||< 1|
|chest pain||4||3||10||10||14||16||< 1|
|proarrhythmia||< 1||< 1||2||4||5||5||3|
|peripheral vascular disorder||1||2||1||1||2||3||< 1|
|cardiovascular disorder||1||< 1||2||2||2||3||< 1|
|vasodilation||1||< 1||1||2||1||3||< 1|
|AICD discharge||< 1||2||2||2||2||3||< 1|
|hypertension||< 1||1||1||1||2||2||< 1|
|sleep problem||1||1||5||5||6||8||< 1|
|altered consciousness||2||3||1||2||3||4||< 1|
|mood change||< 1||< 1||1||3||2||3||< 1|
|appetite disorder||1||2||2||1||3||3||< 1|
|stroke||< 1||< 1||1||1||< 1||1||< 1|
|abdominal pain||< 1||< 1||2||2||2||3||< 1|
|colon problem||2||1||1||< 1||2||3||< 1|
|flatulence||1||< 1||1||1||2||2||< 1|
|pulmonary problem||3||3||5||3||4||8||< 1|
|upper respiratory tract problem||1||1||3||4||3||5||< 1|
|asthma||1||< 1||1||1||1||2||< 1|
|genitourinary disorder||1||0||1||1||2||3||< 1|
|sexual dysfunction||< 1||1||1||1||3||2||< 1|
|abnormal lab value||1||2||3||2||1||4||< 1|
|weight change||1||1||1||< 1||2||2||< 1|
|extremity pain||2||2||4||5||3||7||< 1|
|back pain||1||< 1||2||2||2||3||< 1|
|Skin and Appendages|
|bleeding||1||< 1||1||< 1||2||2||< 1|
|visual problem||1||1||2||4||5||5||< 1|
|a Because patients are counted at each dose level tested, the Any Dose column cannot be determined by adding across the doses.|
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 AEs 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.
Potential Adverse Effects
Foreign marketing experience with sotalol hydrochloride shows an adverse experience 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 lability, slightly clouded sensorium, incoordination, vertigo, paralysis, thrombocytopenia, eosinophilia, leukopenia, photosensitivity reaction, fever, pulmonary edema, hyperlipidemia, myalgia, pruritis, alopecia.
The oculomucocutaneous syndrome associated with the beta-blocker practolol has not been associated with sotalol during investigational use and foreign marketing experience.
Drugs Undergoing CYP450 Metabolism
Sotalol is primarily eliminated by renal excretion; therefore, drugs that are metabolized by CYP450 are not expected to alter the pharmacokinetics of sotalol. Sotalol is not expected to inhibit or induce any CYP450 enzymes; therefore, it is not expected to alter the PK of drugs that are metabolized by these enzymes.
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 (see WARNINGS). There is only limited experience with the concomitant use of Class Ib or Ic antiarrhythmics. Additive Class II effects would also be anticipated with the use of other beta-blocking agents concomitantly with sotalol.
Single and multiple doses of sotalol do not substantially affect serum digoxin levels. 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 CHF, a known risk factor for proarrhythmia, in the patients receiving digoxin. Both digitalis glycosides and beta-blockers slow atrioventricular conduction and decrease heart rate. Concomitant use can increase the risk of bradycardia.
Sotalol should be administered with caution in conjunction with calcium-blocking drugs because of possible additive effects on atrioventricular conduction or ventricular function. Additionally, concomitant use of these drugs may have additive effects on blood pressure, possibly leading to hypotension.
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. Patients treated with sotalol plus a catecholamine depletor should therefore be closely monitored for evidence of hypotension and/or marked bradycardia which may produce syncope.
Insulin and Oral Antidiabetics
Hyperglycemia may occur, and the dosage of insulin or antidiabetic drugs may require adjustment. Symptoms of hypoglycemia may be masked.
Beta-agonists such as salbutamol, terbutaline and isoprenaline may have to be administered in increased dosages when used concomitantly with sotalol.
Beta-blocking drugs may potentiate the rebound hypertension sometimes observed after discontinuation of clonidine; therefore, caution is advised when discontinuing clonidine in patients receiving sotalol.
No pharmacokinetic interactions were observed with hydrochlorothiazide or warfarin.
Administration of 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 sotalol has no effect on the pharmacokinetics or pharmacodynamics of sotalol.
Drugs Prolonging the QT Interval
Sotalol should be administered with caution in conjunction with other drugs known to prolong the QT interval such as Class I and Class III antiarrhythmic agents, phenothiazines, tricyclic antidepressants, astemizole, bepridil, certain oral macrolides, and certain quinolone antibiotics (see WARNINGS).
Drug/Laboratory Test Interactions
The presence of sotalol in the urine may result in falsely elevated levels of urinary metanephrine when measured by fluorimetric or photometric methods. In screening patients suspected of having a pheochromocytoma and being treated with sotalol, a specific method, such as a high performance liquid chromatographic assay with solid phase extraction (e.g., J. Chromatogr. 385:241, 1987) should be employed in determining levels of catecholamines.
Included as part of the "PRECAUTIONS" Section
QT Prolongation And Proarrhythmia
Betapace/Betapace AF can cause serious and potentially fatal ventricular arrhythmias such as sustained VT/VF, primarily Torsade de Pointes (TdP) type ventricular tachycardia, a polymorphic ventricular tachycardia associated with QT interval prolongation. Factors such as reduced creatinine clearance, female sex, higher doses, reduced heart rate, and history of sustained VT/VF or heart failure 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 [see DOSAGE AND ADMINISTRATION].
Correct hypokalemia or hypomagnesemia prior to initiating Betapace/Betapace AF, as these conditions can exaggerate the degree of QT prolongation, and 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.
Proarrhythmic events must be anticipated not only on initiating therapy, but with every upward dose adjustment [see DOSAGE AND ADMINISTRATION].
Avoid use with other drugs known to cause QT prolongation [see DRUG INTERACTIONS].
Bradycardia/Heart Block/Sick Sinus Syndrome
Sinus bradycardia (heart rate less than 50 bpm) occurred in 13% of patients receiving sotalol in clinical trials, and led to discontinuation in about 3% of patients. Bradycardia itself increases the risk of Torsade de Pointes. Sinus pause, sinus arrest and sinus node dysfunction occur in less than 1% of patients. The incidence of 2nd- or 3rd-degree AV block is approximately 1%.
Betapace/Betapace AF is contraindicated in patients with sick sinus syndrome because it may cause sinus bradycardia, sinus pauses, or sinus arrest.
Sotalol produces significant reductions in both systolic and diastolic blood pressures and may result in hypotension. Monitor hemodynamics in patients with marginal cardiac compensation.
New onset or worsening heart failure may occur during initiation or uptitration of sotalol because of its beta-blocking effects. Monitor for signs and symptoms of heart failure and discontinue treatment if symptoms occur.
Cardiac Ischemia after Abrupt Discontinuation
Following abrupt cessation of therapy with beta-adrenergic blockers, exacerbations of angina pectoris and myocardial infarction may occur. When discontinuing chronically administered Betapace/Betapace AF, particularly in patients with ischemic heart disease, gradually reduce the dosage over a period of 1 to 2 weeks, if possible, and monitor the patient. If angina markedly worsens or acute coronary ischemia develops, treat appropriately and consider use of an alternative beta-blocker. Warn patients not to interrupt therapy without their physician’s advice. Because coronary artery disease is common, but may be unrecognized, the abrupt discontinuation of sotalol may unmask latent coronary insufficiency.
Patients with bronchospastic diseases (for example chronic bronchitis and emphysema) should not receive beta-blockers. If Betapace/Betapace AF is to be administered, use the smallest effective dose, to minimize inhibition of bronchodilation produced by endogenous or exogenous catecholamine stimulation of beta-2-receptors.
Masked Signs Of Hypoglycemia In Diabetics
Beta-blockers may mask tachycardia occurring with hypoglycemia, but other manifestations such as dizziness and sweating may not be significantly affected. Elevated blood glucose levels and increased insulin requirements can occur in diabetic patients.
Avoid abrupt withdrawal of beta-blockade in patients with thyroid disease because it may lead to an exacerbation of symptoms of hyperthyroidism, including thyroid storm. Beta-blockade may mask certain clinical signs (for example, tachycardia) of hyperthyroidism.
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.
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.
Carcinogenesis, 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 to 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 to 7122 mg/kg/day (approximately 450 to 750 times the MRHD as mg/kg or 36 to 63 times the MRHD as mg/m2).
Sotalol has not been evaluated in any specific assay of mutagenicity or clastogenicity.
Use In Specific Populations
Both the untreated underlying condition in pregnancy and the use of sotalol in pregnancy cause adverse outcomes to the mother and fetus/neonate (see Clinical Considerations). In animal reproduction studies in rats,early resorptions were increased at 15 times the maximum recommended human dose (MRHD). In rabbits anincrease in fetal death was observed at 2 times the MRHD administered as a single dose. Sotalol did not revealany teratogenic potential in rats or rabbits at 15 and 2 times the MRHD respectively (see Data).
All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. The estimatedbackground risk of major birth defects and miscarriage for the indicated population is unknown. In the UnitedStates (U.S.) general population, the estimated background risk of major birth defects and miscarriage inclinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.
The incidence of VT is increased and may be more symptomatic during pregnancy. Most tachycardia episodes are initiated by ectopic beats and the occurrence of arrhythmia episodes may, therefore, increase during pregnancy. Breakthrough arrhythmias may also occur during pregnancy, as therapeutic treatment levels may be difficult to maintain due to the increased volume of distribution and increased drug metabolism inherent in the pregnant state.
Fetal/Neonatal Adverse Reactions
Sotalol has been shown to cross the placenta and is found in amniotic fluid. From published observational studies, the potential fetal adverse effects of sotalol use during pregnancy are growth restriction, transient fetal bradycardia, hyperbilirubinemia, hypoglycemia, uterine contractions, and possible intrauterine death. Sotalol may have a greater effect on QT prolongation in the immature heart than in the adult heart, and therefore, conveys an increased risk of serious fetal arrhythmia and/or possible intrauterine death. Monitor the newborn for symptoms of beta blockade.
Labor or Delivery
Generally, risk of arrhythmias increases during the labor and delivery process; therefore, considering the proarrhythmia potential of the drug, patients treated with sotalol should be monitored continuously during labor and delivery.
Reproduction studies in rats and rabbits administered sotalol during organogenesis at 15 times and 2 times the MRHD as mg/m2, respectively, did not reveal any teratogenic potential associated with sotalol.
In pregnant rats, sotalol doses administered during organogenesis at approximately 15 times the MRHD as mg/m2, increased the number of early resorptions, while no increase in early resorptions was noted at 2 times the MRHD as mg/m2.
In reproductive studies in rabbits, a sotalol dose (160 mg/kg/day) at 5 times the MRHD as mg/m2 produced a slight increase in fetal death, and maternal toxicity. However, one study from published data reported an increase in fetal deaths in rabbits receiving a single dose (50 mg/kg) at 2 times the MRHD as mg/m2 on gestation day 14.
Limited available data from published literature report that sotalol is present in human milk. The estimated daily infant dose of sotalol received from breastmilk is 0.8-3.4 mg/kg, estimated at 22 to 25.5% of the maternal weight-adjusted dosage of Betapace (see Data). The amount of the drug in breast milk is similar to the neonatal therapeutic dosage. Therefore, there is potential for bradycardia and other symptoms of beta blockade such as dry mouth, skin or eyes, diarrhea or constipation in the breastfed infant. There is no information regarding the effects of sotalol on milk production. Because of the potential serious adverse reactions to the breastfed child and the high level of sotalol in breast milk, advise women not to breastfeed while on treatment with Betapace.
Sotalol is present in human milk in high levels. A prospective study evaluated 20 paired samples of breast milk and maternal blood from 5 mothers who elected to breastfeed. Breast milk samples had a mean sotalol concentration of 10.5 μg/mL (± 1.1 μg/mL; range: 4.8 to 20.2 μg/mL) compared to a simultaneous mean maternal plasma concentration of 2.3 μg/mL (± 0.3 μg/mL; range: 0.8 to 5.0 μg/mL). The mean milk plasma ratio was 5.4:1 (range: 2.2 to 8.8). The estimated daily infant dose was 0.8-3.4 mg/kg, estimated at 22 to 25.5% of the maternal weight-adjusted dosage of sotalol. This is similar to recommended therapeutic dose in neonates. None of the mothers reported any adverse reactions in the breastfed infant.
Females And Males Of Reproductive Potential
Based on the published literature, beta blockers (including sotalol) may cause erectile dysfunction.
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 [see DOSAGE AND ADMINISTRATION and CLINICAL PHARMACOLOGY].
Associated side effects of sotalol use in pediatric patients are those typical of a beta-blocking agent, and lead to discontinuation of the drug in 3 to 6% of patients. As in adults, the Class III antiarrhythmic action of sotalol in pediatric patients is associated with a significant proarrhythmic potential for adverse effects. In pediatric patients, the incidence of proarrhythmic side effects of sotalol varies from 0 to 22%; however, sotalol-induced Torsade de Pointes tachycardias are observed less frequently in the pediatric population.
Proarrhythmic effects of sotalol in pediatric patients included increased ventricular ectopy and exacerbation of bradycardia, the latter predominantly in patients sinus node dysfunction following surgery for congenital cardiac defects. Bradycardia may require emergency pacemaker implantation. Close in-patient monitoring is recommended for several days.
Sotalol is mainly eliminated via the kidneys. Adjust dosing intervals based on creatinine clearance [see DOSAGE AND ADMINISTRATION].
Intentional or accidental overdosage with sotalol hydrochloride has rarely 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 to 16 grams) of sotalol hydrochloride 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
(second and third degree) transvenous cardiac pacemaker.
(depending on associated factors) epinephrine rather than isoproterenol or norepinephrine may be useful.
Aminophylline or aerosol beta-2-receptor stimulant.
Torsade de Pointes
DC cardioversion, transvenous cardiac pacing, epinephrine, magnesium sulfate.
Sotalol hydrochloride is contraindicated in patients with bronchial asthma, sinus bradycardia, second and third degree AV block, unless a functioning pacemaker is present, congenital or acquired long QT syndromes, cardiogenic shock, uncontrolled congestive heart failure, and previous evidence of hypersensitivity to sotalol.
Mechanism Of Action
Sotalol hydrochloride has both betaadrenoreceptor blocking (Vaughan Williams Class II) and cardiac action potential duration prolongation (Vaughan Williams Class III) antiarrhythmic properties. Sotalol hydrochloride is a racemic mixture of d- and l-sotalol. Both isomers 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 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-blockade 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 electrophysiologic effect can be seen at daily doses of 210 mg/m² 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/m² in children.
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 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 to 100 msec in QT and 10 to 40 msec in QTc (see WARNINGS for description of relationship between QTc and Torsade de Pointes type arrhythmias). No significant alteration in QRS interval is 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 to 15 joules) compared to a mean of 16 joules for a nonrandomized 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/m² with dosing every 8 hours for a total 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 steadystate 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 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.
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 hydrochloride 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 nonsignificant 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 hydrochloride produces significant reductions in both systolic and diastolic blood pressures. Although sotalol hydrochloride is usually well-tolerated hemodynamically, caution should be exercised in patients with marginal cardiac compensation as deterioration in cardiac performance may occur (see WARNINGS, Congestive Heart Failure).
Sotalol hydrochloride has been studied in life-threatening and less severe arrhythmias. In patients with frequent premature ventricular complexes (VPC), sotalol hydrochloride was significantly superior to placebo in reducing VPCs, paired VPCs and non-sustained ventricular tachycardia (NSVT); the response was dose-related through 640 mg/day with 80 to 85% of patients having at least a 75% reduction of VPCs. Sotalol hydrochloride was also superior, at the doses evaluated, to propranolol (40 to 80 mg TID) and similar to quinidine (200 to 400 mg QID) in reducing VPCs. In patients with lifethreatening arrhythmias [sustained ventricular tachycardia/fibrillation (VT/VF)], sotalol hydrochloride 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 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] comparing 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). 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 VPC pairs, and at least 70% suppression of VPCs), 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 sotalol hydrochloride in this trial were 320 to 480 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 (e.g., in patients with implanted defibrillators) whether sotalol response causes improved survival or identifies a population with a good prognosis.
In a large double-blind, placebo controlled secondary prevention (postinfarction) trial (n=1,456), sotalol hydrochloride was given as a non-titrated initial dose of 320 mg once daily. Sotalol did not produce a significant increase in survival (7.3% mortality on sotalol vs. 8.9% on placebo, p=0.3), but overall did not suggest an adverse effect on survival. There was, however, a suggestion of an early (i.e., first 10 days) excess mortality (3% on sotalol vs. 2% on placebo). In a second small trial (n=17 randomized to sotalol) where sotalol was administered at high doses (e.g., 320 mg twice daily) to high-risk post-infarction patients (ejection fraction < 40% and either > 10 VPC/hr or VT on Holter), there were 4 fatalities and 3 serious hemodynamic/electrical adverse events within two weeks of initiating sotalol.
In healthy subjects, the oral bioavailability of sotalol hydrochloride is 90 to 100%. After oral administration, peak plasma concentrations are reached in 2.5 to 4 hours, and steady-state plasma concentrations are attained within 2 to 3 days (i.e., after 5 to 6 doses when administered twice daily). Over the dosage range 160 to 640 mg/day sotalol hydrochloride 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 hydrochloride does not bind to plasma proteins and is not metabolized. Sotalol hydrochloride shows very little intersubject variability in plasma levels. The pharmacokinetics of the d and l enantiomers of sotalol are essentially identical. Sotalol hydrochloride 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 (see DOSAGE AND ADMINISTRATION). Age per se does not significantly alter the pharmacokinetics of sotalol hydrochloride, but impaired renal function in geriatric patients can increase the terminal elimination half-life, resulting in increased drug accumulation. The absorption of sotalol hydrochloride was reduced by approximately 20% compared to fasting when it was administered with a standard meal. Since sotalol hydrochloride 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 q 8h in the multi-dose study. After rapid absorption with peak levels occurring on average between 2 to 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. 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%.
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