Letter to the editor
Editor, – Reference is made to the article 'Inside the isomers: the tale of chiral switches' (Aust Prescr 2004;27:109-13). In this article it is asserted that &aos;in overdose, there is a concern about the potential for sudden death, possibly related to QT prolongation due to a secondary metabolite formed from (R)-citalopram. (S)-citalopram (escitalopram) was therefore developed with the aim of a better harm: benefit ratio compared to (R)-citalopram'.
Significantly, the authors of this article have not referenced any of the statements in this paragraph. I would like to advise that the statement regarding the propensity of a metabolite of the (R)-enantiomer of citalopram to cause sudden death as a result of QT prolongation is completely unfounded.
A survey has investigated the effects of citalopram, at therapeutic doses, on ECG parameters.1 The authors concluded that citalopram has no significant effects on PQ, QRS or QTc intervals, during short-or long-term treatment. Nor were there any deaths or clinically significant arrhythmias reported among all pure citalopram intoxications (n=108 with doses up to 5.2 g) over a two-year period in Sweden.2
Since there is absolutely no basis to the assertion that a metabolite of (R)-citalopram is associated with sudden death as a result of QT prolongation, the reason given for the development of (S)-citalopram is also purely speculative and quite simply, untrue.
Medical Department Manager
Baulkham Hills, NSW
- Rasmussen SL, Overo KF, Tanghoj P. Cardiac safety of citalopram: prospective trials and retrospective analyses. J Clin Pyschopharmacol 1999;19:407-15.
- Personne M, Persson H, Sjoberg G. Citalopram toxicity [letter]. Lancet 1997;350:518-9.
- Ostrom M, Eriksson A, Thorson J, Spigset O. Fatal overdose with citalopram [letter]. Lancet 1996;348:339-40.
- Catalano G, Catalano MC, Epstein MA, Tsambiras PE. QTc interval prolongation associated with citalopram overdose: a case report and literature review. Clin Neuropharmacol 2001;24:158-62.
- Eichelbaum M, Testa B, Somogyi A, editors. Stereochemical aspects of drug action and disposition. Handbook of Experimental Pharmacology, Vol 153. Berlin, New York: Springer; 2003.
- Meuleman C, Jourdain P, Bellorini M, Sadeg N, Loiret J, Guillard N, et al. [Citalopram and torsades de pointes. A case report] [French]. Arch Mal Coeur Vaiss 2001;94:1021-4.
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