Atrialside effects

Ventricular Arrhythmia Sotalol (AF) 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 dose of sotalol (AF). 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 (AF) dose according to creatinine clearance and by monitoring the ECG for excessive increases in the QT interval. Treatment with sotalol (AF) must therefore be started only in patients observed for a minimum of three days on their maintenance dose in a facility that can provide electrocardiographic monitoring and in the presence of personnel trained in the management of serious ventricular arrhythmias. Calculation of the creatinine clearance must precede administration of the first dose of sotalol (AF). For detailed instructions regarding dose selection, see DOSAGE AND ADMINISTRATION. Proarrhythmia in Atrial Fibrillation/Atrial Flutter Patients In eight controlled trials of patients with AFIB/AFL and other supraventricular arrhythmias (N=659) there were four cases of Torsade de Pointes reported (0.6%) during the controlled phase of treatment with sotalol (AF). The incidence of Torsade de Pointes was significantly lower in those patients receiving total daily doses of 320 mg or less (0.3%), as summarized in Table 5 below. Both patients who had Torsade de Pointes in the group receiving >320 mg/day were receiving 640 mg/day. In the group receiving ≤320 mg daily, one case of TdP occurred at a daily dose of 320 mg on day 4 of treatment and one case occurred on a daily dose of 160 mg on day 1 of treatment. Table 5 Incidence of Torsade de Pointes in Controlled Trials of AFIB and Other Supraventricular Arrhythmias Sotalol Hydrochloride (AF) (Daily Dose) Any Dose (N=659) >320 mg/day (N=62) ≤320 mg/day (N=597) ≤240 mg/day (N=340) Placebo (N=358) n(%) n(%) n(%) n(%) n(%) Torsade de Pointes 4(0.6%) 2(3.2%) 2(0.3%) 1(0.3%) 0 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 clinical dose-response study. In this clinical trial sotalol (AF) treatment was not initiated if the QT interval was greater than 450 msec and during therapy the dose was reduced or discontinued if the QT interval was ≥520 msec. Experience in patients with ventricular arrhythmias is also pertinent to the risk of Torsade de Pointes in patients with AFIB/AFL (see below). Proarrhythmia in Ventricular Arrhythmia Patients In patients with a history of sustained ventricular tachycardia, the incidence of Torsade de Pointes during sotalol treatment was 4% and worsened VT in about 1%; in patients with other less serious ventricular arrhythmias the incidence of Torsade de Pointes was 1% and new or worsened VT in 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 (QT c ) interval, as shown in Table 6 below. Table 6 Percent Incidence of Torsade de Pointes and Mean QT c Interval by Dose For Patients With Sustained VT/VF Daily Dose (mg) Incidence of Torsade de Pointes Mean QT C * (msec) 80 0 463 160 0.5 467 320 1.6 473 480 4.4 483 640 3.7 490 >640 5.8 512 Number of patients assessed * highest on-therapy value Table 7 below relates the incidence of Torsade de Pointes to on-therapy QT c and change in QT c from baseline. It should be noted, however, that the highest on therapy QT c 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 QT c. Table 7 Relationship Between QT c Interval Prolongation and Torsade de Pointes On-Therapy QT C Interval (msec) Incidence of Torsade de Pointes Change in QT C Interval From Baseline (msec) Incidence of Torsade de Pointes less than 500 1.3% less than 65 1.6% 500 to 525 3.4% 65 to 80 3.2% 525 to 550 5.6% 80 to 100 4.1% >550 10.8% 100 to 130 5.2% >130 7.1% Number of patients assessed 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 QT c 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 (see OVERDOSAGE ). 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. Use with Drugs that Prolong QT Interval and Antiarrhythmic Agents The use of sotalol (AF) 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, bepridil, tricyclic antidepressants, and certain oral macrolides. Class I or Class III antiarrhythmic agents should be withheld for at least three half-lives prior to dosing with sotalol (AF). In clinical trials, sotalol (AF) 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 (AF), because of their potential to prolong refractoriness (see WARNINGS ). There is only limited experience with the concomitant use of Class Ib or Ic antiarrhythmics. Congestive Heart Failure Sympathetic stimulation is necessary in supporting circulatory function in congestive heart failure, and beta-blockade carries the potential hazard of further depressing myocardial contractility and precipitating more severe failure. In patients who have heart failure controlled by digitalis and/or diuretics, sotalol (AF) should be administered cautiously. Both digitalis and sotalol slow AV conduction. As with all beta-blockers, caution is advised when initiating therapy in patients with any evidence of left ventricular dysfunction. In a pooled data base of four placebo-controlled AFIB/AFL and PSVT studies, new or worsening CHF occurred during therapy with sotalol (AF) in 5 (1.2%) of 415 patients. In these studies patients with uncontrolled heart failure were excluded (i.e., NYHA Functional Classes III or IV). In other premarketing sotalol studies, new or worsened congestive heart failure (CHF) occurred in 3.3% (n=3257) of patients and led to discontinuation in approximately 1% of patients receiving sotalol. The incidence was higher in patients presenting with sustained ventricular tachycardia/fibrillation (4.6%, n=1363), or a prior history of heart failure (7.3%, n=696). Based on a life-table analysis, the one-year incidence of new or worsened CHF was 3% in patients without a prior history and 10% in patients with a prior history of CHF. NYHA Classification was also closely associated to the incidence of new or worsened heart failure while receiving sotalol (1.8% in 1395 Class I patients, 4.9% in 1254 Class II patients and 6.1% in 278 Class III or IV patients). Electrolyte Disturbances Sotalol (AF) should not be used in patients with hypokalemia or hypomagnesemia prior to correction of imbalance, 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. Bradycardia/Heart Block The incidence of bradycardia (as determined by the investigators) in the supraventricular arrhythmia population treated with sotalol (AF) (N = 415) was 13%, and led to discontinuation in 2.4% of patients. Bradycardia itself increases the risk of Torsade de Pointes. Recent Acute MI Sotalol has been used in a controlled trial following an acute myocardial infarction without evidence of increased mortality (see Safety in Patients with Structural Heart Disease ). 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. The following warnings are related to the beta-blocking activity of sotalol AF. 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, it is prudent when discontinuing chronically administered sotalol (AF), particularly in patients with ischemic heart disease, to carefully monitor the patient and consider the temporary use of an alternate beta-blocker if appropriate. If possible, the dosage of sotalol (AF) 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 (AF), abrupt discontinuation in patients with arrhythmias may unmask latent coronary insufficiency. Non-Allergic Bronchospasm (e.g., chronic bronchitis and emphysema) PATIENTS WITH BRONCHOSPASTIC DISEASES SHOULD IN GENERAL NOT RECEIVE BETA-BLOCKERS. It is prudent, if sotalol hydrochloride (AF) is to be administered, to use the smallest effective dose, so that inhibition of bronchodilation produced by endogenous or exogenous catecholamine stimulation of beta 2 receptors may be minimized. 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. Diabetes In patients with diabetes (especially labile diabetes) or with a history of episodes of spontaneous hypoglycemia, sotalol (AF) should be given with caution since beta-blockade may mask some important premonitory signs of acute hypoglycemia; e.g., tachycardia. Sick Sinus Syndrome Sotalol (AF) should be used only with extreme caution 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, the risk of Torsade de Pointes with sotalol (AF) therapy is increased, especially after cardioversion. Bradycardia following cardioversion in these patients is associated with QT c interval prolongation which is augmented due to the reverse use dependence of the Class III effects of sotalol (AF). Patients with AFIB/AFL associated with the sick sinus syndrome may be treated with sotalol (AF) if they have an implanted pacemaker for control of bradycardia symptoms. Thyrotoxicosis Beta-blockade may mask certain clinical signs (e.g., tachycardia) of hyperthyroidism. Patients suspected of developing thyrotoxicosis should be managed carefully to avoid abrupt withdrawal of beta-blockade which might be followed by an exacerbation of symptoms of hyperthyroidism, including thyroid storm. The beta-blocking effects of sotalol (AF) may be useful in controlling heart rate in AFIB associated with thyrotoxicosis but no study has been conducted to evaluate this.

Sotalol hydrochloride/Sotalol hydrochloride (AF) tablets are contraindicated in patients with: Sinus bradycardia, sick sinus syndrome, second and third degree AV block, unless a functioning pacemaker is present Congenital or acquired long QT syndromes Cardiogenic shock or decompensated heart failure Serum potassium <4 mEq/L Bronchial asthma or related bronchospastic conditions Hypersensitivity to sotalol For the treatment of AFIB/AFL, sotalol hydrochloride/sotalol hydrochloride AF tablets are also contraindicated in patients with: Baseline QT interval >450 msec For the treatment of AFIB/AFL or ventricular arrythmias Sinus bradycardia, 2 nd or 3 rd degree AV block, sick sinus syndrome Congenital or acquired long QT syndrome Serum potassium <4 mEq/L Cardiogenic shock, decompensated heart failure Bronchial asthma or related bronchospastic conditions Hypersensitivity to sotalol For the treatment of AFIB/AFL also contraindicated for: QT interval >450 msec