Long QT Syndrome Medication

Updated: Nov 30, 2017
  • Author: Ali A Sovari, MD, FACP, FACC; Chief Editor: Mikhael F El-Chami, MD  more...
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Medication

Medication Summary

No treatment addresses the cause of long QT syndrome (LQTS). Antiadrenergic therapeutic measures (eg, use of beta-blockers, left cervicothoracic stellectomy) and device therapy (eg, use of pacemakers, implantable cardioverter-defibrillators [ICD]s) aim to decrease the risk and lethality of cardiac events.

As previously mentioned, the protective effect of beta-blockers is related to their adrenergic blockade, which diminishes the risk of cardiac arrhythmias. They may also reduce the QT interval in some patients. Beta-blockers used in patients with LQTS include the following:

  • Nadolol (preferred)
  • Propranolol
  • Metoprolol
  • Atenolol

Nadolol is the preferred beta blocker to be used at a dose of 1-1.5 mg/kg/day (once a day for patients older than 12 years and divided twice a day for younger patients). [3]

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Beta-Adrenergic Blocking Agents

Class Summary

Antiadrenergic therapy effectively protects most patients with long QT syndrome (LQTS). Beta-blockers, especially propranolol, are the drugs most frequently used in patients with LQTS. Inform patients and their family members that beta-blockers should be continued indefinitely. Interruption in beta-blocker therapy may increase the risk of cardiac events.

Propranolol (Inderal LA, Inderal XL, InnoPran XL, Hemangeol)

Propranolol decreases the effect of sympathetic stimulation on the heart. It decreases conduction through the atrioventricular (AV) node and has negative chronotropic and inotropic effects. Consult a cardiologist because dosing varies and is individualized in patients with LQTS. Patients with asthma should use cardioselective beta-blockers. Patients with LQTS who cannot take beta-blockers may require an ICD as first-line therapy.

Nadolol (Corgard)

Nadolol is frequently prescribed because of its long-term effect. This agent decreases the effect of sympathetic stimulation on the heart. Nadolol decreases conduction through the AV node and has negative chronotropic and inotropic effects. Consult a cardiologist because dosing varies and is individualized in patients with LQTS. Patients with asthma should use cardioselective beta-blockers. Patients with LQTS who cannot take beta-blockers may require an ICD as first-line therapy.

Metoprolol (Lopressor, Toprol XL)

Metoprolol is a selective beta1-adrenergic receptor blocker that decreases the automaticity of contractions. During intravenous (IV) administration, carefully monitor blood pressure, heart rate, and ECG. Consult a cardiologist because dosing varies and is individualized in patients with LQTS. Patients with LQTS who cannot take beta-blockers may require an ICD as first-line therapy.

Atenolol (Tenormin)

Atenolol selectively blocks beta1-receptors with little or no effect on beta2 types. Consult a cardiologist because dosing varies and is individualized in patients with LQTS. Patients with LQTS who cannot take beta-blockers may require an ICD as first-line therapy.

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