BETAPACE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for BETAPACE (BETAPACE).
Class III antiarrhythmic agent; prolongs cardiac action potential duration and refractory period by blocking potassium channels, primarily IKr.
| Metabolism | Not metabolized; excreted unchanged in urine (80-90%) via renal tubular secretion; no significant hepatic metabolism. |
| Excretion | Renal: >90% unchanged drug (sotalol) in urine; biliary/fecal: <10% |
| Half-life | 12 hours (10-20 hours) in patients with normal renal function; prolonged in renal impairment, requiring dose adjustment |
| Protein binding | 0% (not bound to plasma proteins) |
| Volume of Distribution | 2-3 L/kg; distributes into extracellular fluid and myocardium |
| Bioavailability | Oral: 90-100% |
| Onset of Action | Oral: 1-2 hours; IV: within 5 minutes |
| Duration of Action | Oral: 12-24 hours; IV: 4-12 hours; clinically significant beta-blockade persists for at least 12 hours after oral dose |
Oral: 80 mg twice daily; may increase up to 160 mg twice daily as needed.
| Dosage form | TABLET |
| Renal impairment | CrCl 30-50 mL/min: 80 mg once daily; CrCl <30 mL/min: 80 mg every 48 hours; contraindicated if CrCl <10 mL/min. |
| Liver impairment | No adjustment required for mild to moderate impairment; severe impairment (Child-Pugh C): use with caution, consider dose reduction. |
| Pediatric use | Not FDA-approved; limited data: 1-4 mg/kg/day divided twice daily, with close monitoring. |
| Geriatric use | Start at 40 mg twice daily; increase cautiously due to increased sensitivity and renal decline. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for BETAPACE (BETAPACE).
| Breastfeeding | Sotalol is excreted into human breast milk. The milk-to-plasma (M/P) ratio is approximately 3.5 to 5.6, indicating significant accumulation in breast milk. Because of its potential for adverse effects in nursing infants, including bradycardia and hypotension, breastfeeding is generally not recommended during sotalol therapy. If used, monitor the infant for signs of beta-blockade. |
| Teratogenic Risk | Betapace (sotalol) is classified as FDA Pregnancy Category B. Animal studies have shown no evidence of teratogenicity, but there are no adequate and well-controlled studies in pregnant women. Sotalol crosses the placenta and may cause fetal bradycardia, reduced placental perfusion, and hypoglycemia. Use during the first trimester is associated with a potential risk of congenital anomalies, though data are limited. During the second and third trimesters, risks include fetal growth restriction, preterm labor, and neonatal effects such as bradycardia, hypotension, and hypoglycemia. Sotalol should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. |
■ FDA Black Box Warning
Because of its potential to cause life-threatening proarrhythmias (e.g., torsades de pointes), BETAPACE is indicated only for the treatment of documented, life-threatening ventricular arrhythmias.
| Serious Effects |
Sinus bradycardia, sick sinus syndrome, second- or third-degree AV block (unless pacemaker is present), cardiogenic shock, decompensated heart failure, concurrent use with other Class III antiarrhythmics (e.g., amiodarone), hypokalemia, lactation.
| Precautions | Proarrhythmia (torsades de pointes), heart failure exacerbation, electrolyte disturbances (hypokalemia, hypomagnesemia), bradycardia, renal impairment requiring dose adjustment, bronchospasm in patients with asthma/COPD, masking of hypoglycemia in diabetic patients. |
| Food/Dietary | Avoid grapefruit and grapefruit juice as they may increase sotalol concentrations and risk of toxicity. Take on an empty stomach (1 hour before or 2 hours after meals) to avoid food-related absorption interference. Maintain stable intake of potassium and magnesium; avoid excessive dietary changes. |
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| Fetal Monitoring | Monitor maternal heart rate, blood pressure, ECG for QT interval prolongation, and signs of heart failure. Assess fetal heart rate and growth via ultrasound. Monitor for preterm labor. Newborns should be monitored for bradycardia, hypotension, hypoglycemia, and respiratory depression for at least 48 hours after delivery. |
| Fertility Effects | Sotalol has no known direct effects on human fertility. Animal studies have not shown impaired fertility. However, any drug that affects hemodynamics may theoretically influence reproductive function, but no specific data are available. |
| Clinical Pearls | Betapace (sotalol) is a class III antiarrhythmic with non-cardioselective beta-blockade. Use with caution in renal impairment (dose adjustment required for CrCl <60 mL/min). QT prolongation risk increases with hypokalemia, hypomagnesemia, bradycardia, or concurrent QT-prolonging drugs. Initiate and titrate in hospitalized monitored setting due to proarrhythmia risk (including torsades de pointes). Monitor creatinine, electrolytes, and ECG (QTc) regularly. |
| Patient Advice | Take exactly as prescribed; do not skip doses or stop suddenly without talking to your doctor. · Avoid grapefruit juice and grapefruit products as they may increase side effects. · Report symptoms like fainting, fast or irregular heartbeat, dizziness, or shortness of breath immediately. · Do not take other medications (including OTC) without consulting your doctor, especially those for cold, allergy, or asthma. · Keep all appointments for blood tests and ECGs; electrolyte imbalances (low potassium or magnesium) increase risk of dangerous heart rhythms. |