Citalopram

Citalopram 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 , Citrol, Seropram,Talam (Europe and Australia), Recital (Israel, Thrima Inc. for Unipharm Ltd.), Zetalo (India), Celepram, Ciazil (Australia), Zentius (South America, Roemmers), Cilift (South Africa) and Cipram (Denmark, H. Lundbeck A/S).

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History

Citalopram was originally created in 1989,^[1] by the pharmaceutical company Lundbeck. The patent expired in 2003, allowing other companies legally to 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.

Indications

Approved

Citalopram is primarily used to treat the symptoms of depression but can also be prescribed for social anxiety disorder, panic disorder or obsessive-compulsive disorder. Also prescribed in Huntington's disease and premenstrual dysphoric disorder.

Unapproved/Off-label/Investigational

Citalopram has been found to significantly reduce the symptoms of diabetic neuropathy,^[2] and premature ejaculation.^[3] There is also evidence that citalopram may be effective in the treatment of post-stroke pathological crying.^[4]

While on its own Citalopram is less effective than amitriptyline in the prevention of migraines, in refractory cases combination therapy may be more effective.^[5]

Side effects and drug interactions

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.^[6] Citalopram should be taken with caution when using St John's wort.^[7]

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, 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 changes, 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 is bruxism (teeth grinding).^[8] When patients start using citalopram they may experience a feeling similar to electricity or minor shocks in their upper body and in their hands. This is caused by the chemical changes occurring in the brain and they pass with time. Occasionally, panic attacks, thoughts of suicide or self-injury may occur or increase in the first few weeks, before the antidepressant effect starts.^[9]

Citalopram and other SSRIs have been shown to cause sexual side effects in some patients, both males and females.^[10] Although usually reversible, these sexual side effects can sometimes last for months, years or possibly indefinitely even after the drug has been completely withdrawn. This disorder is known as Post SSRI Sexual Dysfunction.

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.^[11]

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.

Stereochemistry

Citalopram has a 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.

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).^[12] In both cases, the salt forms of the amine makes these otherwise lipophilic compounds water-soluble.

References

Lunbeck's official websites for citalopram under the trade name Cipramil:

• Cipramil.com

Forest's official websites for citalopram under the trade name Celexa:

• Celexa.com
• Celexa product page on Forest Laboratories web site
• Cipramil Patient Information Leaflet Cipramil Patient Information Leaflet