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™ , Seropram™ (Europe and Australia), Celepram™ and Ciazil™ (Australia).

History

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

Lundbeck has recently released an updated formulation called escitalopram oxalate (also known as Cipralex™ or Lexapro™), which is simply the S-enantiomer of the racemic citalopram (see below), and acquired a new patent for it.

Indications

Approved

Citalopram is primarily used to treat the symptoms of depression but can also be prescribed for panic disorder or obsessive- compulsive disorders.

Unapproved/Off-label/Investigational

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.

Side effects and drug interactions

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.

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, nausea/vomiting, heightened orgasmic latency in females, impotence 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.

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.

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.The salt form makes these otherwise lipophilic compounds watersoluble.