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Citalopram
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Systematic (IUPAC) name | |
1-[3-(dimethylamino)propyl]-1-(4-fluorophenyl)- 1,3-dihydro[3,4]benzofuran-5-carbonitrile |
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Identifiers | |
CAS number | |
ATC code | N06 | N06AB10
PubChem | |
DrugBank | |
ChemSpider | |
Chemical data | |
Formula | C20H21FN2O |
Mol. mass | 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 in urine |
Therapeutic considerations | |
Pregnancy cat. |
C(US) |
Legal status |
℞ Prescription only |
Routes | Oral |
Citalopram 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, Sweden), Citrol, Seropram, Talam (Europe and Australia), Citabax, Citaxin (Poland), Citalec (Slovakia), Recital (Israel, Thrima Inc. for Unipharm Ltd.), Zetalo (India), Celapram, Ciazil (Australia, New Zealand), Zentius (South America, Roemmers), Ciprapine (Ireland), Cilift (South Africa), Citox (Mexico), and Cipram (Denmark, H. Lundbeck A/S).
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Citalopram (sī-'tal-ǝ-וpram)[1] was originally created in 1989,[2] by the pharmaceutical company Lundbeck. The patent expired in 2003, allowing other companies to legally produce generic versions.
Lundbeck has recently released an updated formulation called escitalopram (also known as Cipralex or Lexapro), which is the S-enantiomer of the racemic citalopram (see below), and acquired a new patent for it. In the United States, Forest Laboratories licenses the rights for both Celexa and Lexapro from Lundbeck, which is based in Denmark.
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.[3]
Citalopram has been found to significantly reduce the symptoms of diabetic neuropathy,[4] and premature ejaculation.[5] There is also evidence that citalopram may be effective in the treatment of post-stroke pathological crying.[6]
While on its own Citalopram is less effective than amitriptyline in the prevention of migraines, in refractory cases combination therapy may be more effective.[7]
Citalopram is generally considered safe and well-tolerated in the therapeutic dose range of 20 to 60 mg/day. A doctor must always monitor a patient taking an SSRI like citalopram. 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.[8] Citalopram should be taken with caution when using St John's wort.[9]
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 antidepressant medications is bruxism (teeth grinding). However there is no evidence directly implicating Citalopram with teeth grinding.[10]
Citalopram and other SSRIs have been shown to cause a preoccupation with sexual content in some patients, both males and females.[11]
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.[12]
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 and severity of discontinuation symptoms.
Citalopram has one stereocenter, to which a 4-fluorophenyl group and an N,N-dimethyl-3-aminopropyl group bind. Due to this chirality the molecule exists in (two) enantiomeric forms (mirror images). They are termed S-(+)-citalopram and R-(−)-citalopram.
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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 S-(+) enantiomer, the generic name of which is escitalopram. Whereas citalopram is supplied as the hydrobromide, escitalopram is sold as the oxalate salt (hydrooxalate).[13] In both cases, the salt forms of the amine makes these otherwise lipophilic compounds water-soluble.
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