Is Lexapro (escitalopram) contraindicated in QT (quantum time) prolongation?

Escitalopram (Lexapro) is Contraindicated in Patients with QT Prolongation

Escitalopram (Lexapro) is contraindicated in patients with pre-existing QT prolongation due to its potential to further prolong the QT interval and increase the risk of torsades de pointes. 1, 2

Evidence for QT Prolongation with Escitalopram

Escitalopram has been documented to cause QT interval prolongation in a dose-dependent manner:

• The FDA label for escitalopram specifically mentions that it can cause QTc prolongation 1
• In clinical studies, escitalopram at 10mg daily caused a mean QTcF change of 4.5 msec from placebo, while a 30mg dose caused a 10.7 msec change 1
• Based on established exposure-response relationship, the predicted QTcF change at the maximum recommended therapeutic dose of 20mg is 6.6 msec 1
• Post-marketing reports have identified torsade de pointes as an adverse reaction with escitalopram 1

Risk Stratification

The risk of QT prolongation and torsades de pointes with escitalopram is significantly higher in patients with:

• Pre-existing QT prolongation
• Female sex
• Age >65 years
• Electrolyte abnormalities (especially hypokalemia, hypomagnesemia)
• Concurrent use of other QT-prolonging medications
• Bradycardia
• Heart failure
• Recent conversion from atrial fibrillation
• Congenital long QT syndrome 3, 2

Management Recommendations

1. For patients with pre-existing QT prolongation:

   • Avoid escitalopram completely 3, 2
   • According to ACC/AHA/ESC guidelines, removal of offending agents is indicated in drug-induced LQTS (Class I recommendation) 3

2. For patients requiring an SSRI who have risk factors for QT prolongation:

   • Consider alternative SSRIs with lower risk of QT prolongation, such as fluoxetine, fluvoxamine, or paroxetine 4
   • Paroxetine appears to have the lowest risk of QT prolongation among SSRIs 4

3. If escitalopram must be used in patients without pre-existing QT prolongation:

   • Obtain baseline ECG before starting treatment 2
   • Monitor ECG at 2 weeks, then monthly thereafter 2
   • Obtain additional ECG after adding any new QT-prolonging medication 2
   • Maintain potassium in high-normal range (4.5-5 mmol/L) 2
   • Ensure magnesium levels are above 1.8 mg/dL 2
   • Use lower doses when possible 1, 5

Clinical Evidence of Risk

Several case reports have documented QT prolongation and torsades de pointes with escitalopram:

• QT prolongation has been reported even with low-dose escitalopram (5 mg/day) after just 2 days of treatment 5
• Overdose cases have shown significant QT prolongation requiring ECG monitoring for at least 2 days 6
• Similar SSRIs like citalopram have been associated with QT prolongation and torsades de pointes at therapeutic doses 7

Monitoring Recommendations

If a patient is already on escitalopram:

• Perform ECG monitoring to assess QT interval
• Consider discontinuation if QTc is ≥500 ms or increases by >60 ms from baseline 2, 1
• Monitor electrolytes regularly, especially potassium and magnesium 2
• Be vigilant for symptoms of arrhythmias (palpitations, dizziness, syncope)
• Avoid adding other QT-prolonging medications 2

Conclusion

Based on the most recent and highest quality evidence, escitalopram should be avoided in patients with pre-existing QT prolongation due to the increased risk of torsades de pointes and sudden cardiac death. Alternative antidepressants with lower risk of QT prolongation should be considered for these patients.