Synopsis: Escitalopram (Lexapro) is the active s-enantiomer of the selective serotonin reuptake inhibitor (SSRI), citalopram (Celexa). It is labeled for the treatment of major depressive disorder.

Safety: To date, no serious adverse effects have been associated with escitalopram. One study¹ demonstrated a slightly greater likelihood of activation of mania/hypomania in the treatment group as compared with the placebo group (0.1 percent versus zero percent). Therefore, as with other antidepressants, escitalopram should be used with caution in patients with a history of mania or hypomania. Escitalopram has not been evaluated in patients with seizure disorder or in patients with recent myocardial infarction or unstable heart disease. Because escitalopram has weak or negligible effects on the cytochrome P450 system, the potential for drug interactions is low.² However, as with other SSRIs, escitalopram should not be used in combination with a monoamine oxidase inhibitor (MAOI), or within 14 days of discontinuing an MAOI. It also should not be given with citalopram because it is the active isomer of that drug. Escitalopram is classified in pregnancy category C, and there have been no studies evaluating the risk of its use in nursing mothers.¹

Tolerability: The tolerability profile of escitalopram is predictable and similar to that of citalopram.³ In research trials, pooled dropout rates because of adverse events in patients taking escitalopram, 10 mg daily, were similar to those in patients receiving placebo (4.2 versus 2.5 percent; P = .5).⁴ Nausea, insomnia, somnolence, and sexual dysfunction (ejaculation disorder) are more common than with placebo and are dosage related.

Effectiveness: In comparison with placebo, escitalopram at dosages of both 10 mg and 20 mg daily decreases scores from baseline in the MADRS (Montgomery Asberg Depression Rating Scale), HAM-D (Hamilton Rating Scale for Depression), and CGI-S (Clinical Global Impression-Severity Scale) more than placebo.⁴ Of note, citalopram, in a dosage of 40 mg daily, was not more effective than escitalopram at 10 mg daily on the majority of the major efficacy outcome variables.² While there are limited data comparing escitalopram to other SSRIs or other classes of antidepressants, one would expect it to be as effective as citalopram, which is in turn similar in efficacy to fluoxetine (Prozac).⁵ In people who respond to treatment, escitalopram is more effective than placebo in preventing relapse over 36 weeks of continued therapy (26 versus 40 percent, absolute risk reduction: 14 percent; number needed to treat: 7.)² Escitalopram has not been studied in patients younger than 18 years.

Price: A one-month supply of escitalopram (10 mg daily) costs approximately $67, compared with $72 for citalopram (20 mg daily), $80 for generic fluoxetine (20 mg daily), $80 for sertraline (Zoloft; 50 mg daily), and $84 for paroxetine (Paxil; 20 mg daily). Prices are based on the starting dosage for each drug, as listed in Red Book, Montvale, N.J.: Medical Economics Data, 2003.⁶

Simplicity: Escitalopram is available as scored 10-mg and 20-mg tablets. The recommended starting dosage is 10 mg once daily.

Bottom line: While escitalopram has proved to be an effective treatment for major depression, it has not been shown to be significantly more effective, safer, or better tolerated than citalopram or other antidepressants.