Citalopram vs Escitalopram for Anxiety
Escitalopram is recommended as a first-line treatment for generalized anxiety disorder over citalopram, with a starting dose of 10mg daily and a maximum dose of 20mg daily. 1
Comparative Efficacy and Pharmacology
Escitalopram is the therapeutically active S-enantiomer of racemic citalopram, while the R-enantiomer is essentially pharmacologically inactive. This distinction is important for several reasons:
- Escitalopram is more potent and selective for serotonin reuptake inhibition than citalopram 2
- Escitalopram achieves therapeutic effects at half the dosage of citalopram 2
- Escitalopram has demonstrated earlier onset of action compared to citalopram in clinical studies 3
In pooled analyses of placebo-controlled trials, escitalopram showed statistically significant improvements in anxiety symptoms after just 1 week of treatment, while citalopram required 4 weeks to show statistical separation from placebo 3.
Dosing Recommendations
For anxiety disorders:
- Escitalopram: 10mg daily initially, may increase to maximum 20mg daily 1
- Higher doses of SSRIs may be required for anxiety disorders compared to depression 1
FDA Approval and Evidence
Escitalopram has established efficacy for Generalized Anxiety Disorder (GAD) in three 8-week, multicenter, flexible-dose, placebo-controlled studies that demonstrated statistically significant greater mean improvement compared to placebo on the Hamilton Anxiety Scale (HAM-A) 4.
Clinical Considerations
Advantages of Escitalopram
- More favorable pharmacokinetic profile with once-daily dosing (27-33 hour half-life) 5
- Linear and dose-proportional pharmacokinetics 5
- Lower potential for drug interactions due to negligible effects on cytochrome P450 enzymes 6
- Low protein binding (56%), reducing likelihood of interactions with highly protein-bound drugs 5
Side Effect Profile
- Most common adverse events include nausea (mild and transient), ejaculatory problems, diarrhea, insomnia, dry mouth, and somnolence 6
- Generally well-tolerated with a low rate of discontinuation due to adverse events 6
Special Populations
No dosage adjustment is typically necessary for:
- Adolescents
- Elderly individuals
- Patients with hepatic impairment 5
Important Precautions
- Use caution when combining escitalopram with other serotonergic medications 1
- Never combine escitalopram with MAOIs (14-day washout period required) 1
- Monitor for suicidal ideation/behavior, especially during medication transitions 1
- Gradual tapering is essential when discontinuing to prevent discontinuation syndrome 1
Treatment Duration
Treatment should be continued for at least 9-12 months after symptom remission, and never discontinued abruptly due to the risk of discontinuation syndrome 1.
When discontinuing, a gradual taper is recommended:
- Reduce dose by 50% for 1 week
- Reduce by another 50% for another week before stopping 1