title: Variation in lamotrigine plasma concentrations with hormonal contraceptive monthly cycles in patients with epilepsy.
abstract: OBJECTIVE
  This is the first report comparing intrasubject lamotrigine (LTG) plasma concentrations between hormonal contraceptive (HC) intake and week-off phases in epilepsy patients receiving combined LTG and HC treatment. We describe the variation in LTG plasma concentrations with hormonal contraceptive (HC) monthly intake cycles in a series of eight patients with epilepsy.
  
  
  METHODS
  Venous blood samples were prospectively drawn from patients before their first morning dose of LTG, once between days 18 and 21 of HC intake and once between days 5 and 7 of the HC-free week.
  
  
  RESULTS
  Median LTG plasma concentrations were significantly higher during the HC washout week than during the phase of HC intake (p = 0.02). The median value of intrasubject percentage increase was 27%, with a wide interpatient variability.
  
  
  CONCLUSIONS
  These findings are in line with a preliminary report on healthy volunteers. Standardization of blood sampling in relation to HC intake cycles is advisable when planning LTG therapeutic monitoring in patients receiving HC.
authors.affiliation: Neurology Clinic, Department of Neurological Sciences, University of Bologna, Bologna, Italy. manuela.contin@unibo.it
authors.forename: Manuela
authors.initials: M
authors.lastname: Contin
authors.forename: Fiorenzo
authors.initials: F
authors.lastname: Albani
authors.forename: Giovanni
authors.initials: G
authors.lastname: Ambrosetto
authors.forename: Patrizia
authors.initials: P
authors.lastname: Avoni
authors.forename: Francesca
authors.initials: F
authors.lastname: Bisulli
authors.forename: Roberto
authors.initials: R
authors.lastname: Riva
authors.forename: Paolo
authors.initials: P
authors.lastname: Tinuper
authors.forename: Agostino
authors.initials: A
authors.lastname: Baruzzi
mesh_terms: D000293:Adolescent; D000328:Adult; D000927:Anticonvulsants / Q000097:blood* / Q000493:pharmacokinetics / Q000627:therapeutic use*; D003278:Contraceptives, Oral, Hormonal / Q000008:administration & dosage* / Q000493:pharmacokinetics; D004334:Drug Administration Schedule; D004347:Drug Interactions; D016903:Drug Monitoring; D004827:Epilepsy / Q000097:blood* / Q000188:drug therapy*; D005260:Female; D006801:Humans; D000077213:Lamotrigine; D008875:Middle Aged; D010507:Periodicity; D011446:Prospective Studies; D014227:Triazines / Q000097:blood* / Q000493:pharmacokinetics / Q000627:therapeutic use*
chemical_list: D000927:Anticonvulsants; D003278:Contraceptives, Oral, Hormonal; D014227:Triazines; D000077213:Lamotrigine