Pharmacokinetic consequences of a citalopram treatment discontinuation

In this pilot study, the pharmacokinetics of citalopram (CIT) were examined in five hospitalized depressed patients after an abrupt discontinuation of a treatment with 40 mg/d of this selective serotonin reuptake inhibitor (S SRI). During the 8-day study period, clinical ratings were regularly carrie d out. Between days 5 and 8, the patients were treated with clomipramine (7 5 mg/d). The enantiomers of CIT and its metabolites, demethyl-CIT (DCIT) an d CIT-propionic acid derivative (CIT-PROP), were measured repeatedly from d ay 0 to day 8 by a stereoselective high-performance liquid chromatography ( HPLC) procedure. The following drug plasma half-lives were measured (means +/- SD): R-CIT: 66 +/- 11 h; S-CIT: 42 +/- 13 h; R-DCIT: 228 +/- 148 h; S-D CIT: 93 +/- 35 h; R-CIT-PROP: 82 +/- 31 h; S-CIT-PROP: 186 +/- 93 h.