Warnings for Betapace AF
Included as part of the "PRECAUTIONS" Section
Precautions for Betapace AF
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.
Hypotension
Sotalol produces significant reductions in both systolic and diastolic blood pressures and may result in hypotension. Monitor hemodynamics in patients with marginal cardiac compensation.
Heart Failure
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.
Bronchospasm
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.
Thyroid Abnormalities
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.
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.
Nonclinical Toxicology
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
Pregnancy
Risk Summary
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.
Clinical Considerations
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.
Data
Animal Data
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.
Lactation
Risk Summary
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.
Data
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
Infertility
Based on the published literature, beta blockers (including sotalol) may cause erectile dysfunction.
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 [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.
Renal Impairment
Sotalol is mainly eliminated via the kidneys. Adjust dosing intervals based on creatinine clearance [see DOSAGE AND ADMINISTRATION].