What are the management steps for an 88-year-old lady with an incidental overdose of sotalol (beta blocker) 80mg pills, presenting with prolonged QTc (corrected QT) interval of 508ms?

From the Guidelines

For an 88-year-old lady with an incidental sotalol overdose and prolonged QTc of 508 ms, immediate discontinuation of sotalol and close monitoring in a hospital setting is crucial to prevent torsades de pointes and other life-threatening arrhythmias. The patient should be continuously monitored with cardiac telemetry until QTc normalizes. According to the guidelines outlined in 1, removal of the offending agent, in this case, sotalol, is indicated for patients with drug-induced long QT syndrome.

Key steps in management include:

• Discontinuing sotalol immediately
• Monitoring the patient in a hospital setting with continuous cardiac telemetry until QTc normalizes
• Checking electrolytes, particularly potassium, magnesium, and calcium, and correcting any abnormalities promptly
• Maintaining potassium above 4.0 mEq/L and magnesium above 2.0 mg/dL
• Obtaining serial ECGs to track QTc changes
• Avoiding all other QT-prolonging medications
• Considering activated charcoal if the overdose was very recent (within 1-2 hours)
• Watching for signs of Torsades de Pointes (TdP), such as dizziness, syncope, or palpitations

If TdP occurs, preparation for administering IV magnesium sulfate (1-2g), temporary overdrive pacing, or isoproterenol is essential, as suggested by 1. The patient should remain monitored until QTc returns to baseline, typically 2-4 days after sotalol discontinuation due to its 12-hour half-life. Sotalol causes QT prolongation in a dose-dependent manner by blocking potassium channels, and elderly patients are at higher risk due to decreased renal clearance and higher sensitivity to the drug's effects, as noted in 1 and 1.

From the FDA Drug Label

OVERDOSAGE Intentional or accidental overdosage with sotalol has rarely resulted in death. Symptoms and Treatment of Overdosage The most common signs to be expected are bradycardia, congestive heart failure, hypotension, bronchospasm and hypoglycemia In cases of massive intentional overdosage (2 to 16 grams) of sotalol the following clinical findings were seen: hypotension, bradycardia, cardiac asystole, prolongation of QT interval, Torsade de Pointes, ventricular tachycardia, and premature ventricular complexes. If overdosage occurs, therapy with Sotalol AF should be discontinued and the patient observed closely Because of the lack of protein binding, hemodialysis is useful for reducing sotalol plasma concentrations. Patients should be carefully observed until QT intervals are normalized and the heart rate returns to levels >50 bpm Torsade de Pointes: DC cardioversion, transvenous cardiac pacing, epinephrine, magnesium sulfate.

The patient should be closely observed until QT intervals are normalized and the heart rate returns to levels >50 bpm. Given the prolonged QTC interval of 508, there is a risk of Torsade de Pointes. The following therapeutic measures are suggested:

• DC cardioversion
• Transvenous cardiac pacing
• Epinephrine
• Magnesium sulfate 2

From the Research

Management of Sotalol Overdose

• The patient has taken an incidental overdose of sotalol 80mg pills, resulting in a prolonged QTc interval of 508ms, which increases the risk of torsade de pointes 3, 4.
• Torsade de pointes is a life-threatening arrhythmia that requires immediate attention and treatment 5, 6.
• The management of sotalol-induced torsade de pointes includes correcting any underlying electrolyte imbalances, such as hypokalaemia or hypomagnesiaemia, and administering magnesium infusion or lidocaine to suppress the arrhythmia 5, 6.

Risk Factors for Torsade de Pointes

• The patient's age and prolonged QTc interval increase the risk of torsade de pointes 4.
• Other risk factors for torsade de pointes include reduced left ventricular function, bradycardia, and daily doses of sotalol exceeding 320mg 4.
• The patient's renal function should also be assessed, as sotalol is renally excreted and reduced renal function can increase the risk of torsade de pointes 4.

Treatment Options

• Magnesium infusion has been shown to be effective in treating sotalol-induced torsade de pointes 6.
• Lidocaine may also be used to suppress torsade de pointes, especially if magnesium infusion is not effective 5.
• The patient should be closely monitored for any signs of torsade de pointes, and the treatment should be adjusted accordingly 3, 4.