2.1 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.
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
Dose
Volume of SOTYLIZE
5 mg/mL solution
80 mg
16 mL
120 mg
24 mL
160 mg
32 mL
240 mg
48 mL
320 mg
64 mL
2.2 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 [see Dosage and Administration (2.1)]. 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 × 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 × 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.
2.3 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 [see Dosage and Administration (2.1)]. If that dose level at steady-state does not acceptably reduce the time to 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.
2.4 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.