General
Description & Use
Escitalopram (trade names Lexapro, Cipralex) is the pure (S) enantiomer
of citalopram and is a selective serotonin reuptake inhibitor
(SSRI). Escitalopram is used in the treatment of depression and
anxiety.
Escitalopram
(Lexapro, Cipralex, Citadep S, Feliz S, Sipralexa and Seroplex)
is an antidepressant of the selective serotonin reuptake inhibitor
(SSRI) class. It is approved for the treatment of major depressive
disorder and generalized anxiety disorder; other indications include
social anxiety disorder, panic disorder and obsessive-compulsive
disorder. Escitalopram is the S-stereoisomer (enantiomer) of the
earlier Lundbeck drug citalopram (Celexa), hence the name escitalopram.
Escitalopram is noted for its high selectivity of serotonin reuptake
inhibition and, as a result has fewer side effects not related
to its serotonergic activity. Escitalopram acts by increasing
intrasynaptic levels of the neurotransmitter serotonin by blocking
the reuptake of the neurotransmitter into the neuron. Of the SSRIs
currently on the market escitalopram has the highest affinity
for the human serotonin transporter (SERT). Another enantiomer
of citalopram (R-citalopram) counteracts to a certain degree the
serotonin-enhancing action of escitalopram. As a result, escitalopram
is a more potent antidepressant than citalopram, which is a mixture
of escitalopram and R-citalopram. In order to explain this phenomenon,
researchers from Lundbeck proposed that escitalopram enhances
its own binding via an additional interaction with another allosteric
site on the transporter. Further research by the same group showed
that R-citalopram also enhances binding of escitalopram, and therefore
the allosteric interaction cannot explain the observed counteracting
effect. However, in the most recent paper the same authors again
reversed their findings and reported that R-citalopram decreases
binding of escitalopram to the transporter. Although allosteric
binding of escitalopram to the serotonin transporter is of unquestionable
research interest, its clinical relevance is unclear since the
binding of escitalopram to the allosteric site is at least 1000
times weaker than to the primary binding site.
In vitro studies using human liver microsomes
indicated that CYP3A4 and CYP2C19 are the primary isozymes involved
in the N-demethylation of escitalopram.
Citalopram
(Celexa) is an antidepressant
drug used to treat major depression associated with mood disorders.
It is also used on occasion in the treatment of body dysmorphic
disorder and anxiety.
Citalopram
belongs to a class of drugs known as selective serotonin reuptake
inhibitors (SSRIs). It is sold under the brand-names Celexa (U.S.
and Canada, Forest Laboratories, Inc.), Cipramil (Australia),
Citrol, Seropram,Talam (Europe and Australia), Citabax, Citaxin
(Poland), Citalec (Slovakia), Recital (Israel, Thrima Inc. for
Unipharm Ltd.), Zetalo (India), Celapram, Ciazil (Australia),
Zentius (South America, Roemmers), Ciprapine (Ireland), Cilift
(South Africa), Citox (Mexico), and Cipram (Denmark, H. Lundbeck
A/S).
Citalopram
is used to treat the symptoms of major depression, social anxiety
disorder and panic disorder.
Citalopram
is a Pgp substrate and is actively transported by that protein
from the brain. The efficacy of citalopram in people possessing
a certain version of Pgp (genetic TT-allele) is likely to be diminished.
This suggests that in non-responders to citalopram a switch to
antidepressant which is not a Pgp substrate, such as fluoxetine
(Prozac) or mirtazapine (Remeron) but not to venlafaxine (Effexor),
amitriptyline (Elavil) or paroxetine (Paxil), which are Pgp substrates,
may be beneficial.
Citalopram has been found to significantly reduce the symptoms
of diabetic neuropathy, and premature ejaculation. There is also
evidence that citalopram may be effective in the treatment of
post-stroke pathological crying. While on its own Citalopram is
less effective than amitriptyline in the prevention of migraines,
in refractory cases combination therapy may be more effective.
Side effects and drug interactions
Citalopram is generally considered safe and well-tolerated in
the therapeutic dose range of 20 to 60 mg/day. Distinct from some
other agents in its class, citalopram exhibits linear pharmacokinetics
and minimal drug interaction potential, making it a better choice
for the elderly or comorbid patients. Citalopram should be taken
with caution when using St John's wort.
Citalopram can have a number of adverse effects. In clinical trials,
over 10% of patients reported one or more of the following side
effects: fatigue, drowsiness, dry mouth, increased sweating (hyperhidrosis),
trembling, headache, dizziness, sleep disturbances, insomnia,
cardiac arrhythmia, hallucinations, blood pressure changes, nausea
and/or vomiting, diarrhea, heightened anorgasmia in females, impotence
and ejaculatory problems in males. In rare cases (around over
1% of cases), some allergic reactions, convulsions, mood swings,
anxiety and confusion have been reported. Also sedation may be
present during treatment of citalopram. If this occurs it is advisable
to take the dose at bedtime instead of in the morning.
Another
uncommon side effect of some anti-depressant medications is bruxism
(teeth grinding). However there is no evidence directly implicating
Citalopram with teeth grinding. Citalopram and other SSRIs have
been shown to cause sexual side effects in some patients, both
males and females. Citalopram is contraindicated in individuals
taking MAOIs. SSRI discontinuation syndrome has been reported
when treatment is stopped. Tapering off citalopram therapy, as
opposed to abrupt discontinuation, is recommended in order to
diminish the occurrence of discontinuation symptoms.
