Article: Citalopram

Citalopram
Systematic (IUPAC) name
1-(3-dimethylaminopropyl)-1-(4-fluorophenyl)-1,3-dihydroisobenzofuran-5-carbonitrile
Identifiers
CAS number	59729-33-8
ATC code	N06AB04 N06AB10
PubChem	2771
DrugBank	APRD00147
Chemical data
Formula	C20H22N2FO
Mol. weight	324.392 g/mol
Pharmacokinetic data
Bioavailability	80%
Metabolism	hepatic (CYP3A4 & CYP2C19)
Half life	35 hours
Excretion	Mostly as unmetabolized Citalopram, partly DCT and traces of DDCT
Therapeutic considerations
Pregnancy cat.	C
Legal status	℞ Prescription only
Routes	Oral

Citalopram or nitalapram is an antidepressant drug used to treat 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., Forest Laboratories, Inc.), Cipramil™ (Europe and Australia).

History

Citalopram was originally created by the pharmaceutical company Lundbeck although the patent for it expired in 2003, allowing other companies to legally produce generic versions.

Lundbeck has recently released a new SSRI drug called escitalopram oxalate (also known as Cipralex™ or Lexapro™) derived from the citalopram molecule.

Indications

Approved

Citalopram is primarily used to treat the symptoms of depression but can also be prescribed for panic disorder.

Unapproved/Off-label/Investigational

Citalopram has been found to significantly reduce the symptoms of diabetic neuropathy^[1] and premature ejaculation^[2].

There is also evidence that citalopram may be effective in the treatment of post-stroke pathological crying^[3].

Side effects

Citalopram is 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.[1]

Citalopram can have a number of adverse effects. In clinical trials, over 10% of patients reported fatigue, drowsiness, dry mouth, increased sweating (Hyperhidrosis), trembling, headache and/or dizziness, sleep disturbances, arrythmia, blood pressure and ejaculatory problems. In rare cases (around over 1% of cases), some allergic reactions, convulsions, mood changes, anxiety and confusion have been reported. Occasionally, panic attacks, thoughts of suicide or self-harm may occur or increase in the first few weeks, before the antidepressant effect starts.[2]

Citalopram is contraindicated in individuals taking MAOIs. It is considered relatively safe in overdose, although fatal cases of dosages 840 mg to 1960 mg have been reported.[3]

Stereochemistry

Citalopram has a chiral carbon atom, to which a 4-fluorophenyl group and an N,N-dimethyl-3-aminopropyl group are bonded. This stereocentre leads to the existence of two enantiomers of citalopram. They are termed S-(+)-citalopram and R-(−)-citalopram.

S-(+)-citalopram	R-(−)-citalopram

Citalopram is sold as a racemic mixture, consisting of 50% R-(−)-citalopram and 50% S-(+)-citalopram. Only the S-(+) enantiomer has the desired antidepressant effect. Lundbeck now markets the pure S-(+) enantiomer, the generic name of which is escitalopram. Escitalopram is sold as the oxalate - that is, the nitrogen atoms of the tertiary amine functional groups of two S-(+)-citalopram molecules are protonated by oxalic acid to form two escitalopram ammonium cations and an oxalate anion.

→