What is stronger, Lexapro (escitalopram) or Zoloft (sertraline)?

Comparison of Escitalopram (Lexapro) and Sertraline (Zoloft)

Escitalopram (Lexapro) is generally considered stronger than sertraline (Zoloft) in terms of potency per milligram, with escitalopram 10mg showing comparable or superior efficacy to sertraline at higher doses (50-200mg). 1, 2

Potency and Efficacy Comparison

• Escitalopram is the S-enantiomer of citalopram and has been shown to have higher potency per milligram than sertraline:

  • Escitalopram 10mg daily has demonstrated similar efficacy to sertraline flexibly dosed from 50-200mg daily (with mean sertraline dosage of 144mg/day) 2
  • Escitalopram has allosteric properties in addition to SSRI effects, which may contribute to its enhanced potency 1

• Clinical response rates:

  • In comparative studies, escitalopram showed response rates of 90% at 10-20mg/day compared to 97% for sertraline at 100-150mg/day 3
  • Remission rates were 74% for escitalopram versus 77% for sertraline 3

Side Effect Profiles

• Both medications have favorable safety profiles, but with some differences:
  • Escitalopram has been associated with fewer adverse effects (45%) compared to sertraline (56%) 3
  • Sertraline has moderate drug interaction issues compared to escitalopram, which has minimal drug interactions 1
  • Both medications may cause sexual dysfunction, with weighted mean incidence across observational studies of approximately 40% 4

Pharmacokinetic Considerations

• Escitalopram:

  • Half-life of 27-33 hours, allowing once-daily dosing 5
  • Reaches steady-state concentrations within 7-10 days 5
  • Low protein binding (56%) and minimal inhibitory effects on CYP enzymes 5

• Sertraline:

  • Of the SSRIs, sertraline has been extensively studied in cardiovascular disease and appears to have a lower risk of QTc prolongation than escitalopram 4

Clinical Applications

• For severe depression:

  • Escitalopram has demonstrated superior efficacy in severe major depressive disorder compared to citalopram (its racemic parent) 6
  • Both escitalopram and sertraline are effective for major depressive disorder 4, 2

• For special populations:

  • In cardiovascular disease, sertraline may be preferable due to lower risk of QTc prolongation 4
  • For anxiety disorders, both medications are effective, with escitalopram recommended as a first-line treatment for anxiety in adolescents 7

Dosing Considerations

• Escitalopram is typically dosed at 10-20mg daily, while sertraline requires 50-200mg daily for comparable effect 2
• This difference in dosing range reflects escitalopram's higher potency per milligram

Common Pitfalls and Caveats

• QT prolongation risk: Escitalopram carries a dose-dependent risk of QT prolongation, with boxed warnings not to exceed doses of 20mg per day in adults over 60 years 4
• Drug interactions: Sertraline has moderate drug interaction potential, while escitalopram has minimal interaction issues 1
• When switching between these medications, a cross-taper approach is typically recommended to minimize withdrawal symptoms

In conclusion, while both medications are effective SSRIs, escitalopram demonstrates higher potency per milligram and potentially better tolerability, making it "stronger" in terms of therapeutic effect at lower doses compared to sertraline.