PURPOSE: 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.
RCT Entities:
PURPOSE: This is the first report comparing intrasubject lamotrigine (LTG) plasma concentrations between hormonal contraceptive (HC) intake and week-off phases in epilepsypatients 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.