Citalopram

General Information

Citalopram is a member of the group of selective serotonin reuptake inhibitors (SSRIs) that includes fluoxetine, paroxetine and sertraline and has been used clinically as an antidepressant since 1984. Adult doses of 20 - 60 mg are to be taken once daily. The S-enantiomer, escitalopram, is also available as a pharmaceutical agent.

Citalopram is known to undergo biotransformation via mono- and di-N-demethylation, oxidative deamination, N-oxide formation and glucoronide conjugation. The mono-N-desmethyl metabolite (desmethylcitalopram) has 25-50% of the pharmacological activity of the parent drug.

Adverse effects associated with citalopram therapy include drowsiness, somnolence, hyponatremia, dizziness and tachycardia. Hepatotoxicity has also been reported. The coadministration of monoamine oxidase inhibitors (MAOIs, e.g. hydrazines) is contraindicated due to the possibility of developing serotonin syndrome. Serotonin syndrome has also occured in patients receiving fentanyl, linezolid, meperidine or tramadol. Acute overdosage of 600 mg or more of citalopram may cause EKG abnormalities, whereas doses in excess of 1900 mg may often result in seizures.