title: Effect of grapefruit juice on bioavailability of montelukast.
abstract: OBJECTIVE
  The aim of this study was to investigate possible interactions between grapefruit juice and montelukast for up to 4 hours.
  
  
  METHODS
  A prospective, crossover study with 23 healthy volunteers was performed in two sessions.
  
  
  METHODS
  In the first session, volunteers were treated with oral montelukast 10 mg once daily with 250 ml water. After a 10-day washout period, the same volunteers were treated with 10 mg montelukast with 250 ml grapefruit juice. Blood samples were collected 2, 3, and 4 hours after drug administration and kept at -80°C after both applications. Plasma samples were analyzed for montelukast concentration.
  
  
  RESULTS
  The mean plasma concentration of montelukast across all time intervals was significantly greater (P = 0.0001) for those given grapefruit juice (517, 484, and 440) versus those treated with water (366, 356, and 292). Moreover, with respect to the time the sample was collected, there was no significant difference (P = 0.13) in the mean total plasma concentration up to 4 hours after montelukast ingestion for either group. There was a significant difference between the groups according to the area under curve with regard to marginal and cumulative values for all different time intervals (P < 0.05).
  
  
  CONCLUSIONS
  Plasma concentration of montelukast was higher when administered with grapefruit juice, as compared to with water. This may have been due to the effect of grapefruit on liver metabolism of montelukast and the cytochrome P450 system.
authors.affiliation: Department of Otorhinolaryngology, Osmangazi University, Medical Faculty, Eskisehir, Turkey.
authors.forename: Cemal
authors.initials: C
authors.lastname: Cingi
authors.forename: Sema Zer
authors.initials: SZ
authors.lastname: Toros
authors.forename: Melek Kezban
authors.initials: MK
authors.lastname: Gürbüz
authors.forename: Iskender
authors.initials: I
authors.lastname: Ince
authors.forename: Hamdi
authors.initials: H
authors.lastname: Cakli
authors.forename: Nagehan
authors.initials: N
authors.lastname: Erdogmus
authors.forename: Ercument
authors.initials: E
authors.lastname: Karasulu
authors.forename: Ercan
authors.initials: E
authors.lastname: Kaya
mesh_terms: D000085:Acetates / Q000493:pharmacokinetics*; D000328:Adult; D018927:Anti-Asthmatic Agents / Q000493:pharmacokinetics*; D001628:Beverages / Q000009:adverse effects*; D001682:Biological Availability; D032083:Citrus paradisi; D018592:Cross-Over Studies; D003521:Cyclopropanes; D005260:Female; D018565:Food-Drug Interactions; D006801:Humans; D008297:Male; D011446:Prospective Studies; D011804:Quinolines / Q000493:pharmacokinetics*; D013440:Sulfides; D055815:Young Adult
chemical_list: D000085:Acetates; D018927:Anti-Asthmatic Agents; D003521:Cyclopropanes; D011804:Quinolines; D013440:Sulfides; C093875:montelukast