title: Influence of CYP3A4 induction/inhibition on the pharmacokinetics of vilazodone in healthy subjects.
abstract: OBJECTIVE
  Vilazodone is a serotonin reuptake inhibitor and 5-HT1A partial agonist approved for the treatment of major depressive disorder in adults. Vilazodone seems to be metabolized primarily by the cytochrome P-450 (CYP) 3A4 isozyme and non-CYP-mediated pathways; concomitant use of drugs that affect CYP3A4 activity could potentially alter systemic exposure to vilazodone. The present studies evaluated whether CYP3A4 inhibition (study 1) or induction (study 2) affected the pharmacokinetics of vilazodone.
  
  
  METHODS
  Participants were healthy adult volunteers. Study 1 was conducted in 2 parts and evaluated the pharmacokinetics of single-dose vilazodone administered with multiple-dose (200 mg once daily) ketoconazole, a CYP3A4 inhibitor. Part 1 was an open-label pharmacokinetic assessment of a single 5-mg vilazodone dose with or without ketoconazole. Part 2 was a randomized, double-blind, placebo-controlled, crossover study comparing vilazodone pharmacokinetics after a single 10-mg dose alone or co-administered with ketoconazole or placebo. Study 2 was an open-label, multiple-dose, single-sequence study evaluating the effect of steady-state carbamazepine, a CYP3A4 substrate and inducer, on the pharmacokinetics of steady-state vilazodone (40 mg once daily). Primary pharmacokinetic parameters for both studies were AUC and Cmax for vilazodone. Lack of pharmacokinetic interaction was concluded if the 90% CIs of the ratio of vilazodone plus the CYP3A4 inhibitor/inducer relative to vilazodone alone (or plus placebo) for AUC and Cmax were within the 80% to 125% range. Subject-reported and investigator-identified adverse events (AEs), laboratory values, vital signs, and 12-lead ECG parameters were recorded.
  
  
  RESULTS
  In study 1/parts 1 and 2 (n = 15 and 22 enrolled, respectively), mean vilazodone AUC increased 42% and 51%, respectively, in the presence of ketoconazole (expected to be at steady state) versus vilazodone alone (part 1) or with placebo (part 2). The upper limit of the 90% CIs for the vilazodone AUC and Cmax geometric mean ratios exceeded 125%. In study 2 (n = 30 enrolled), co-administration of vilazodone and the carbamazepine extended-release formulation decreased mean steady-state vilazodone exposure ~45%, and the 90% CIs for the vilazodone AUC and Cmax geometric mean ratios were not within the range of 80% to 125%. In both studies, most AEs were of mild intensity, and gastrointestinal AEs predominated.
  
  
  CONCLUSIONS
  These results suggest that up to a 50% decrease of vilazodone dosage should be considered when it is given in combination with strong CYP3A4 inhibitors; conversely, increasing the vilazodone dosage up to a maximum of 80 mg/d should be considered when it is given in combination with strong CYP3A4 inducers. (Study registration numbers: SB-659746/029; VLZ-PK-02.).
authors.affiliation: Forest Research Institute, Inc, Harborside Financial Center, Jersey City, New Jersey. Electronic address: ramesh.boinpally@frx.com.
authors.forename: Ramesh
authors.initials: R
authors.lastname: Boinpally
authors.affiliation: Forest Research Institute, Inc, Harborside Financial Center, Jersey City, New Jersey.
authors.forename: Nayra
authors.initials: N
authors.lastname: Gad
authors.affiliation: Forest Research Institute, Inc, Harborside Financial Center, Jersey City, New Jersey.
authors.forename: Samir
authors.initials: S
authors.lastname: Gupta
authors.affiliation: Forest Research Institute, Inc, Harborside Financial Center, Jersey City, New Jersey.
authors.forename: Antonia
authors.initials: A
authors.lastname: Periclou
mesh_terms: D000293:Adolescent; D000328:Adult; D002220:Carbamazepine / Q000494:pharmacology*; D018592:Cross-Over Studies; D065701:Cytochrome P-450 CYP3A Inducers / Q000494:pharmacology*; D065692:Cytochrome P-450 CYP3A Inhibitors / Q000494:pharmacology*; D003865:Major Depressive Disorder; D004311:Double-Blind Method; D004347:Drug Interactions; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007654:Ketoconazole / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D000069503:Vilazodone Hydrochloride / Q000008:administration & dosage / Q000493:pharmacokinetics*; D055815:Young Adult
chemical_list: D065701:Cytochrome P-450 CYP3A Inducers; D065692:Cytochrome P-450 CYP3A Inhibitors; D002220:Carbamazepine; D007654:Ketoconazole; D000069503:Vilazodone Hydrochloride
keywords: CYP3A4; carbamazepine; depression; ketoconazole; pharmacokinetics; vilazodone