BETAPACE AF
Clinical safety rating: caution
Comprehensive clinical and safety monograph for BETAPACE AF (BETAPACE AF).
Sotalol is a class III antiarrhythmic agent that also has non-cardioselective beta-adrenergic receptor blocking activity. It prolongs the cardiac action potential duration by blocking potassium channels (IKr), thereby prolonging the QT interval and refractory periods.
| Metabolism | Sotalol is not metabolized; it is excreted unchanged by the kidneys via glomerular filtration and tubular secretion. No metabolites have been identified. |
| Excretion | Primarily renal (unchanged drug and metabolites); approximately 40% excreted as unchanged sotalol in urine, with additional metabolites via fecal route (~10%). Biliary excretion minimal (<5%). |
| Half-life | Terminal elimination half-life: 12 hours (range 10–20 hours) in patients with normal renal function; prolonged in renal impairment (up to 42 hours in severe impairment). |
| Protein binding | ~30% bound to plasma proteins (mainly albumin). |
| Volume of Distribution | 1.6–2.4 L/kg, indicating extensive extravascular distribution. |
| Bioavailability | Oral: 90–100% (well absorbed, minimal first-pass effect). |
| Onset of Action | Oral: 2–4 hours (max effect at steady state). |
| Duration of Action | Duration: ~24 hours for antiarrhythmic effect, sustained with once-daily dosing due to long half-life. |
80 mg orally twice daily. For atrial fibrillation/flutter, initiate at 80 mg twice daily; may increase after 2-3 days to 120 mg twice daily if needed. Maximum 120 mg twice daily.
| Dosage form | TABLET |
| Renal impairment | Contraindicated if CrCl < 40 mL/min. For CrCl 40-60 mL/min: start at 80 mg once daily. For CrCl > 60 mL/min: no adjustment needed. |
| Liver impairment | No specific Child-Pugh based guidelines; use caution in severe hepatic impairment due to reduced clearance. |
| Pediatric use | Not approved for pediatric use; safety and efficacy not established. |
| Geriatric use | Initiate at lower doses (e.g., 80 mg once daily) due to age-related renal impairment; monitor heart rate and ECG closely. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for BETAPACE AF (BETAPACE AF).
| Breastfeeding | Sotalol is excreted in breast milk with a milk-to-plasma ratio of approximately 5.4. The relative infant dose is estimated at 0.3-0.7 mg/kg/day (about 30-70% of maternal weight-adjusted dose). Risk of infant bradycardia and hypoglycemia; caution advised. Monitor infant for signs of beta-blockade. |
| Teratogenic Risk | FDA Pregnancy Category D. First trimester: risk of fetal bradycardia, hypotonia, and hypoglycemia. Second and third trimesters: risk of intrauterine growth restriction (IUGR), placental insufficiency, and preterm delivery. Neonatal effects include bradycardia, hypoglycemia, and respiratory depression lasting 24-72 hours. |
■ FDA Black Box Warning
Sotalol can cause life-threatening ventricular arrhythmias (e.g., torsade de pointes) due to QT interval prolongation. Initiation or dose increases must be carried out in a hospital setting with continuous ECG monitoring. Electrolyte abnormalities, especially hypokalemia and hypomagnesemia, increase the risk.
| Serious Effects |
["Sinus bradycardia (<50 bpm)","Heart block greater than first degree (unless pacemaker)","Congestive heart failure (NYHA Class III or IV)","Cardiogenic shock","QT interval >450 msec (males) or >470 msec (females) at baseline","Hypokalemia (<4 mEq/L) or hypomagnesemia","Concurrent use with other QT-prolonging drugs","Bronchial asthma or COPD with bronchospasm","Diabetes mellitus prone to hypoglycemia (relative)"]
| Precautions | ["Proarrhythmic effects (torsade de pointes) especially with hypokalemia, hypomagnesemia, or bradycardia","Exacerbation of heart failure or hypotension","Bradycardia and heart block","Bronchospasm in patients with asthma or COPD","Masking of hypoglycemia in diabetic patients","Renal impairment requires dose adjustment","Abrupt withdrawal may exacerbate angina or precipitate myocardial infarction"] |
| Food/Dietary |
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| Fetal Monitoring | Monitor maternal heart rate, blood pressure, ECG (QTc interval), and serum potassium and magnesium levels. Fetal monitoring includes fetal heart rate, growth via ultrasound, and nonstress testing in third trimester. Neonatal monitoring for bradycardia, hypoglycemia, and respiratory distress after delivery. |
| Fertility Effects | No specific human studies on fertility. In animal studies, no adverse effects on fertility at clinically relevant doses. Beta-blockers may theoretically impair uterine contractility during labor, but no conclusive data on fertility. |
| Avoid grapefruit and grapefruit juice. Limit alcohol intake. Maintain consistent potassium and magnesium intake; avoid excessive dietary changes or supplements without monitoring. No specific restrictions beyond these. |
| Clinical Pearls | BETAPACE AF (sotalol) is a class III antiarrhythmic with beta-blocker activity. Used specifically for maintenance of normal sinus rhythm in patients with symptomatic atrial fibrillation/flutter. Must be initiated in a setting with continuous ECG monitoring and cardiac resuscitation capabilities due to risk of proarrhythmia (torsades de pointes). Correct hypokalemia and hypomagnesemia before use. Renal function dictates dosing; adjust CrCl <60 mL/min. Avoid with other QT-prolonging drugs. Monitor QTc interval; discontinue if >500 msec. |
| Patient Advice | Take exactly as prescribed; do not skip doses or double up. · Do not stop suddenly; abrupt cessation can worsen heart rhythm. · Report dizziness, fainting, palpitations, or shortness of breath immediately. · Avoid grapefruit juice as it may increase drug levels. · Avoid alcohol and other medications without doctor approval. · Notify healthcare provider of any new medications (prescription, OTC, herbal). · Have regular blood tests to monitor kidney function and electrolyte levels. · May cause fatigue, weakness, or slow heart rate; caution when driving. |