On August 15, 2002, it was announced by Forest Laboratories, Inc. that their new antidepressant Lexapro (escitalopram oxalate) had received FDA approval. Lexapro, the single-isomer of Celexa, is reported to be well-tolerated and may offer some distinct advantages over the drug it is derived from.

How It Is Different from Celexa?

At the chemical level, Celexa is a mixture of two mirror image halves called S- and R-enantiomers. The R-enantiomer does not contribute to the antidepressant effect so it was removed, leaving only the therapeutically active S-enantiomer. The new drug that this process created is Lexapro.

Advantages of Lexapro Over Celexa

Lexapro is reported to have a few advantages over its predecessor, Celexa.

The first is its potency. The recommended dose is 10 mg per day. In clinical trials, this was comparable to the higher titrated dose of Celexa at 40 mg daily.

Another benefit noted was rapid response. Patients taking this drug had a significant improvement in symptoms within one to two weeks of beginning therapy.

Clinical Trials

Lexapro's approval was based upon efficacy and safety data gathered from clinical trials involving 1,100 people, including men and women aged 18-65 with moderate to severe depression.

In a pooled analysis of three eight-week studies of Lexapro, Celexa and placebo, it was found that Lexapro was statistically superior to placebo beginning at week one and continuing throughout the study period.

It was well-tolerated and had a drop out rate comparable to placebo at the 10 mg dosage. The most common adverse events (number given in parentheses are Lexapro vs. placebo) were: nausea (15% vs. 7%), insomnia (9% vs. 4%), ejaculation disorder (9% vs. <1%), somnolence (6% vs. 2%), sweating increased (5% vs. 2%) and fatigue (5% vs. 2%).