Review of pharmacokinetic and pharmacodynamic interaction studies with citalopram.

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Brosen K, Naranjo CA

Review of pharmacokinetic and pharmacodynamic interaction studies with citalopram.

Eur Neuropsychopharmacol. 2001 Aug;11(4):275-83.

PubMed ID

11532381 [ View in PubMed

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Abstract

Citalopram is a selective serotonin reuptake inhibitor that is N-demethylated to N-desmethylcitalopram partially by CYP2C19 and partially by CYP3A4 and N-desmethylcitalopram is further N-demethylated by CYP2D6 to the likewise inactive metabolite di-desmethylcitalopram. The two metabolites are not active. The fact that citalopram is metabolised by more than one CYP means that inhibition of its biotransformation by other drugs is less likely. Besides citalopram has a wide margin of safety, so even if there was a considerable change in serum concentration then this would most likely not be of clinical importance. In vitro citalopram does not inhibit CYP or does so only very moderately. A number of studies in healthy subjects and patients have confirmed, that this also holds true in vivo. Thus no change in pharmacokinetics or only very small changes were observed when citalopram was given with CYP1A2 substrates (clozapine and therophylline), CYP2C9 (warfarin), CYP2C19 (imipramine and mephenytoin), CYP2D6 (sparteine, imipramine and amitriptyline) and CYP3A4 (carbamazepine and triazolam). At the pharmacodynamic level there have been a few documented cases of serotonin syndrome with citalopram and moclobemide and buspirone. It is concluded that citalopram is neither the source nor the cause of clinically important drug-drug interactions.

DrugBank Data that Cites this Article

Drug Enzymes

Drug	Enzyme	Kind	Organism	Pharmacological Action	Actions
Citalopram	Cytochrome P450 2C19	Protein	Humans	No	Substrate Inhibitor	Details
Citalopram	Cytochrome P450 3A4	Protein	Humans	No	Substrate Inhibitor	Details