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.
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 and are dose related.
Ventricular Arrhythmias
Serious Adverse Reactions
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%. Incidence of Torsade de Pointes arrhythmias in patients with VT/VF are shown in Table 3 below.
Table 3: Percent Incidence of Torsade de Pointes and Mean QTc Interval by Dose For Patients With Sustained VT/VF( ) Number of patients assessed *highest on-therapy value |
Daily Dose (mg) | Torsade de Pointes Incidence | Mean QTc * (msec) |
80 | 0 (69) | 463 (17) |
160 | 0.5 (832) | 467 (181) |
320 | 1.6 (835) | 473 (344) |
480 | 4.4 (459) | 483 (234) |
640 | 3.7 (324) | 490 (185) |
>640 | 5.8 (103) | 512 (62) |
Table 4 below relates the incidence of Torsade de Pointes to on-therapy QTc and change in QTc from baseline in patients with ventricular arrhythmias. 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 4: Relationship Between QTc Interval Prolongation and Torsade de Pointes| ( ) Number of patients assessed |
On-Therapy QTc Interval (msec) | Incidence of Torsade de Pointes | Change from Baseline in QTc (msec) | Incidence of Torsade de Pointes |
<500 | 1.3% (1787) | <65 | 1.6% (1516) |
500-525 | 3.4% (236) | 65-80 | 3.2% (158) |
525-550 | 5.6% (125) | 80-100 | 4.1% (146) |
>550 | 10.8% (157) | 100-130 | 5.2% (115) |
| | >130 | 7.1% (99) |
Table 5: Incidence (%) of Common Adverse Reactions (≥ 2% in the Placebo group and less frequent than in the Betapace groups) in a Placebo-controlled Parallel-group Comparison Study of Patients with Ventricular EctopyBody System/Adverse Reaction (Preferred Term) | Placebo | Betapace Total Daily Dose |
|---|
N = 37 (%) | 320 mg N = 38 (%) | 640 mg N = 39 (%) |
|---|
CARDIOVASCULAR | | | |
Chest Pain | 5.4 | 7.9 | 15.4 |
Dyspnea | 2.7 | 18.4 | 20.5 |
Palpitation | 2.7 | 7.9 | 5.1 |
Vasodilation | 2.7 | 0.0 | 5.1 |
NERVOUS SYSTEM | | | |
Asthenia | 8.1 | 10.5 | 20.5 |
Dizziness | 5.4 | 13.2 | 17.9 |
Fatigue | 10.8 | 26.3 | 25.6 |
Headache | 5.4 | 5.3 | 7.7 |
Lightheaded | 8.1 | 15.8 | 5.1 |
Sleep Problem | 2.7 | 2.6 | 7.7 |
RESPIRATORY | | | |
Upper Respiratory Tract Problem | 2.7 | 2.6 | 12.8 |
SPECIAL SENSES | | | |
Visual Problem | 2.7 | 5.3 | 0.0 |
The most common adverse reactions leading to discontinuation of Betapace in trials of patients with ventricular arrhythmias are: fatigue 4%, bradycardia (less than 50 bpm) 3%, dyspnea 3%, proarrhythmia 3%, asthenia 2%, and dizziness 2%. Incidence of discontinuation for these adverse reactions was dose related.
One case of peripheral neuropathy that resolved on discontinuation of Betapace and recurred when the patient was rechallenged with the drug was reported in an early dose tolerance study.
Pediatric Patients
In an unblinded multicenter trial of 25 pediatric 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 prolongation (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.
Atrial Fibrillation/Atrial Flutter
Placebo-controlled Clinical Trials
In a pooled clinical trial population consisting of 4 placebo-controlled studies with 275 patients with atrial fibrillation (AFIB)/atrial flutter (AFL) treated with 160 to 320 mg doses of Betapace AF, the following adverse reactions presented in Table 6 occurred in at least 2% of placebo-treated patients and at a lesser rate than Betapace-treated patients. The data are presented by incidence of reactions in the Betapace AF and placebo groups by body system and daily dose.
Table 6: Incidence (%) of Common Adverse Reactions (≥ 2% in the Placebo group and less frequent than in the Betapace AF groups) in Four Placebo-controlled Studies of Patients with AFIB/AFLBody System/Adverse Reaction (Preferred Term) | Placebo | Betapace AF Total Daily Dose |
|---|
N = 282 (%) | 160-240 mg N = 153 (%) | > 240-320 mg N = 122 (%) |
|---|
CARDIOVASCULAR | | | |
Bradycardia | 2.5 | 13.1 | 12.3 |
GASTROINTESTINAL | | | |
Diarrhea | 2.1 | 5.2 | 5.7 |
Nausea/Vomiting | 5.3 | 7.8 | 5.7 |
Pain abdomen | 2.5 | 3.9 | 2.5 |
GENERAL | | | |
Fatigue | 8.5 | 19.6 | 18.9 |
Hyperhidrosis | 3.2 | 5.2 | 4.9 |
Weakness | 3.2 | 5.2 | 4.9 |
MUSCULOSKELETAL/CONNECTIVE TISSUE | | | |
Pain musculoskeletal | 2.8 | 2.6 | 4.1 |
NERVOUS SYSTEM | | | |
Dizziness | 12.4 | 16.3 | 13.1 |
Headache | 5.3 | 3.3 | 11.5 |
RESPIRATORY | | | |
Cough | 2.5 | 3.3 | 2.5 |
Dyspnea | 7.4 | 9.2 | 9.8 |
Overall, discontinuation because of unacceptable adverse events 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 Betapace AF were: fatigue 4.6%, bradycardia 2.4%, proarrhythmia 2.2%, dyspnea 2%, and QT interval prolongation 1.4%.