Escitalopram
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Escitalopram
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| Systematic (IUPAC) name | |
| S-(+)-1-[3-(dimethylamino)propyl]- 1-(p-fluorophenyl)- 5-phthalancarbonitrileoxalate |
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| Identifiers | |
| CAS number | |
| ATC code | N06 |
| PubChem | |
| DrugBank | |
| Chemical data | |
| Formula | C20H21FN2O |
| Mol. mass | 324.392 g/mol (414.40 as oxalate) |
| Pharmacokinetic data | |
| Bioavailability | 80% |
| Protein binding | ~56% |
| Metabolism | Liver, specifically the enzymes CYP3A4 and CYP2C19 |
| Half life | 27-32 hours |
| Excretion | ? |
| Therapeutic considerations | |
| Pregnancy cat. |
C |
| Legal status |
℞ Prescription only |
| Routes | Oral |
Escitalopram (Cipralex) is a medication developed by the Danish pharmaceutical company Lundbeck, that acts as a selective serotonin reuptake inhibitor (SSRI). It is approved for the treatment of major depressive disorder, generalized anxiety disorder, social anxiety disorder, panic disorder and obsessive compulsive disorder. In the United States the drug is marketed under the name Lexapro by Forest Laboratories. Elsewhere escitalopram is marketed under various brand names such as Cipralex, Lexapro, Sipralexa and Seroplex by Lundbeck. [1]
Escitalopram is the eutomer (i.e., the enantiomer of a chiral compound that is more effective for a particular action) of the racemic drug citalopram. Specifically, it consists of the S-enantiomer. Escitalopram has the highest affinity to the human serotonin transporter SERT and different from other SSRI binds to both, the primary and the allosteric binding site of the SERT.[2]. The allosteric binding has a self-potentiating effect of the binding to the primary binding site, leading to a more effecte serotonin-reuptake inhibition. However the increased activity has been argued by some experts to be statistically and clinically insignificant.
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[edit] History
Escitalopram oxalate is derived from the drug citalopram which is a mixture of two mirror-image isomers, only one of which (S-citalopram) is thought to be responsible for the antidepressive effect of the medication, while the other (R-citalopram) has been shown to counteract the antidepressive effect. Lundbeck has split the isomers apart, taken the active isomer and has licensed it as the new drug Escitalopram. Escitalopram is the pure S-enantiomer (left-handed isomer) of the racemic bicyclic phthalane derivative citalopram, and is the most selective SSRI[3].
Escitalopram was released two years before the patent for citalopram was due to expire. The expiration of a patent means other companies can legally produce cheaper generic versions. On May 23, 2006, the FDA approved a generic version of escitalopram by Teva[2]. However, on July 14th, 2006 the the US District Court of Delaware decided in favour of Lundbeck regarding a patent infringement dispute and ruled the patent on escitalopram valid.[3]
Critics have argued that escitalopram, and the subsequent marketing campaign to persuade mental health professionals to prescribe it, is a ploy to promote sales of a virtually identical but considerably more expensive drug. However preclinical as well as various clinical studies have shown differentiated effects of citalopram and escitalopram [4]. as well as a clinical superiority compared to a variety of other SSRI, such as paroxetine [5]. especially in severely depressed patients and sertraline. Compared to newer serotonin-norepinephrine reuptake inhibitors such as venlafaxine [6]. and duloxetine [7]. escitalopram has shown to be at least as effective.
[edit] Dosing
The recommended dosage of Lexapro is 10-20 mg a day. Exceptions include the elderly, who should only take up to 10 mg a day, and pregnant women in their third trimester should not use Lexapro at all.[8] As both Generalized Anxiety Disorder (GAD) and Depression are both considered chronic conditions, treatment is recommended for several months. However, the efficacy of Lexapro over long periods of time has not been studied, therefore consistent reevaluation of the treatment is recommended for longer periods of treatment.[8]
[edit] Side effects
The side effect profile of escitalopram is close to that of other SSRI with nausea, somnolence and gastronintestinal side effects, leading. SSRIs have been shown to cause sexual side effects in most patients, both males and females[9]. Although usually reversible, these sexual side effects can sometimes last after discontinuation. This disorder is known as Post SSRI Sexual Dysfunction. It may also cause weight gain in certain people. It may cause dizziness after exercise in children.
[edit] Discontinuation symptoms
Discontinuation from antidepressants, especially abruptly, has been known to cause certain withdrawal symptoms. One possible discontinuation symptom from Escitalopram is a type of spontaneous nerve pulse known as paresthesia or "electric shock sensations", described by some patients as a feeling of small electric shocks, which may be accompanied by dizziness. These pulses may be short in duration, only milliseconds long, may affect any region of the body, and recur up to several times a minute, throughout all waking hours. They can be increased by physical activity, but are not solely linked to muscular activity. Other discontinuation symptoms include extreme sensitivity to loud sounds and bright lights, chills, hot flushes, cold sweats, reddening of the face, abdominal pain, weight gain and extreme mental fatigue. Also possible is severe irritability and sadness/depression like symptoms.[10]
[edit] Footnotes
- ^ http://www.lundbeck.com/products/our_products/cipralex/default.asp
- ^ C. Sanchez (2006). "The pharmacology of citalopram enantiomers: the antagonism by R-citalopram on the effect of S-citalopram.". Basic Clin Pharmacol Toxicol 99: 91-5. PMID 16918708.
- ^ M. J. Owens and J. F. Rosenbaum (April 2002). "Escitalopram: a second-generation SSRI". CNS Spectr. 7 (4 supplement 1). PMID 15131491.
- ^ Moore N and Verdoux H and Fantino B (May 2005). "Prospective, multicentre, randomized, double-blind study of the efficacy of escitalopram versus citalopram in outpatient treatment of major depressive disorder.". Int Clin Psychopharmacol 20 (3). PMID 15812262.
- ^ Boulenger JP and Huusom AK and Florea I and Baekdal T and Sarchiapone M (Jul 2006). "A comparative study of the efficacy of long-term treatment with escitalopram and paroxetine in severely depressed patients.". Curr Med Res Opin 22 (7). PMID 16834832.
- ^ Bielski RJ and Ventura D and Chang CC (Sep 2004). "A double-blind comparison of escitalopram and venlafaxine extended release in the treatment of major depressive disorder.". J Clin Psychiatry 65 (9). PMID 15367045.
- ^ Nierenberg AA and Greist JH and Mallinckrodt JH and Prakash A and Sambunaris A and Tollefson GD and Wohlreich MM (Feb 2007). "Duloxetine versus escitalopram and placebo in the treatment of patients with major depressive disorder: onset of antidepressant action, a non-inferiority study.". Curr Med Res Opin 23 (2). PMID 17288694.
- ^ a b Forest Laboratories, [1]
- ^ A. Clayton, A. Keller and E.L. McGarvey (2006). "Burden of phase-specific sexual dysfunction with SSRIs.". J Affect Disord 91: 27-32. PMID 16430968.
- ^ Lexapro -- Warnings. RxList (12/08/2004). Retrieved on 2006-10-22.
[edit] External links
- Lexapro (Forest Laboratories) Official Lexapro Homepage
- Cipralex (Lundbeck) Official Cipralex Homepage
- Pharmacological information Lexapro
- Lexapro Feedback Depression Blog
- Lexapro Ratings and Patient Feedback Lexapro Patient Feedback
- Links to external chemical sources
