Citalopram
Citalopram. Racemic SSRI. The S-enantiomer (escitalopram) is the pharmacologically active form; R-enantiomer may antagonise activity via… Oral half-life 37 h.
Racemic SSRI. The S-enantiomer (escitalopram) is the pharmacologically active form; R-enantiomer may antagonise activity via allosteric SERT site. Dose-dependent QT prolongation.
PK: ITS CITATION WAS A BIOEQUIVALENCE ABSTRACT REPORTING ONLY AUC, Cmax AND tmax — none of the four stored values. F 0.8 is nevertheless RIGHT, verbatim in a real intravenous-and-oral study: "The absolute bioavailability of citalopram tablets in healthy subjects was 80%", which also gives 36.8 h against an unsourced 35. ka 1.5 IS A BACK-DERIVATION: against the old half-life it reproduces 2.92 h, and the cited abstract states "3 (1-6) hours (reference)". V 840 L survives only because deleting it would invoke a resolver default twenty-fold too small; it is 12 L/kg x 70, hand-scaled, and it under-predicts its own citation AUC by 40%. Two published quantities disagree about what should replace it — the paper own exposure implies about 530 L, an independent oral clearance implies about 1100 — so no number is invented. THE ENANTIOMER PAIR IS INTERNALLY INCONSISTENT: this racemate transporter affinity is stored as equal to pure escitalopram, which would require the R-enantiomer to be equipotent, while escitalopram own citation says it "was approximately 30-fold more potent than R-citalopram".
Pharmacokinetics
- Oral — t½ 36.8 h · F 80% · Vd 840 L
Related compounds
- Escitalopram — synergistic
Sources: PMID:10674711, PMID:9681666