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Escitalopram (Lexapro)

Escitalopram in Brief

Generic name : Escitalopram oxalate
Brand names: Lexapro, Lexaprin, Cipralex, Sipralexa, Seroplex
Therapeutic class: Antidepressant
Pharmacologic class: Selective serotonin reuptake inhibitor (SSRI)
FDA Approved: August 14, 2002
Patent expiration date: March 14, 2012
Chemical Formula: C20H21N2FO
Pregnancy Category: C
Habit forming? No
Originally discovered: 1997, Denmark

Based on "Essential Psychopharmacology"
written by Stephen M. Stahl, MD, PhD

History

Escitalopram was developed in a short time space of 3.5 years by the Danish pharmaceutical company Lundbeck. By comparison, new drug development process normally takes 5-6 years. Escitalopram oxalate was developed by isolating a part of the citalopram HBr molecule, known as an isomer.

In the summer of 1997, H. Lundbeck A/S and Forest Laboratories, Inc. decided to develop escitalopram for the treatment of depression. Two years later, in August 1999, the first patients participated in the clinical studies which provide the clinical documentation for marketing authorisation. The pivotal clinical phase III studies were already completed in June 2000, and the first clinical results were publicly presented in December 2000 2.

In December 2001, Lundbeck received Swedish approval for the treatment of depression and panic disorder, and in January 2002, the product was approved in Switzerland for the treatment of depression. By May 2002 it had been approved in Belgium, Denmark, the UK, France, Iceland, Luxembourg, Norway and Austria, as a result of the European Mutual Recognition Procedure.

In the US, Forest submitted an NDA in March 2001 and in January 2002, Forest received an approvable letter from the FDA for escitalopram. By March 2002, Lundbeck had started to supply escitalopram to Forest 9. The FDA issued the approval of escitalopram for major depression in August 2002 and for generalized anxiety disorder in December 2003.

On March 14, 2012 Teva Pharmaceutical Industries/IVAX Pharmaceuticals gained U.S. FDA approval for the first generic Lexapro (escitalopram) tablets.

FDA approved indications

Major Depressive Disorder
Generalized Anxiety Disorder

In March 2009, the US FDA approved Lexapro for the acute and maintenance treatment of depression in adolescents between 12 and 17 years of age.

Off-label & Investigational uses

obsessive-compulsive disorder 11
panic disorder 13
social anxiety disorder 14
posttraumatic stress disorder
premenstrual dysphoric disorder 15
pathological gambling 12
menopause-related symptoms in women 16

Escitalopram "pros" and "cons"

Advantages:

high rates of remission 3
fast onset of antidepressant effect, ususally within 2 weeks 5, 6
significantly reduces relapse rates in depression and generalized anxiety disorder 7, 8
well-tolerated (discontinuation rate < 2% in clinical trials)
low potential for clinically significant drug interactions
superior to other SSRIs in severe depression 4, 10
fewer discontinuation symptoms than with paroxetine and venlafaxine 8
less severe weight gain and sexual problems

Disadvantages:

High costs despite generic availability
Causes sexual dysfunction17 and weight gain

Mechanism of action

Escitalopram is the S-enantiomer of the racemate (citalopram). Pharmacological studies have shown that the R-enantiomer is not inert but counteracts the serotonin-enhancing properties of the S-enantiomer in citalopram.

The antidepressant action of escitalopram is presumably linked to the potentiation of serotonergic activity in the central nervous system resulting from its inhibitory effect on the reuptake of 5-HT from the synaptic cleft. Escitalopram is a highly selective serotonin reuptake inhibitor. Escitalopram has no, or minimal effect on noradrenaline, dopamine and gamma-amino butyric acid (GABA) uptake.

Time to clear out the system

The elimination half-life of escitalopram is about 27-33 hours and is consistent with once-daily administration.

Onset of action

The pharmacokinetics of escitalopram are linear over the clinical dosage range. Steady state plasma levels are achieved within 7-10 days of administration.

Escitalopram tends to work faster than other SSRIs. In clinical studies, many patients treated with Lexapro began to feel better within 1 or 2 weeks 5, 6, although the full antidepressant effect may take 4 to 6 weeks.