Variation in lamotrigine plasma concentrations with hormonal contraceptive monthly cycles in patients with epilepsy.
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.
Contin
Manuela
M
Neurology Clinic, Department of Neurological Sciences, University of Bologna, Bologna, Italy. manuela.contin@unibo.it
Albani
Fiorenzo
F
Ambrosetto
Giovanni
G
Avoni
Patrizia
P
Bisulli
Francesca
F
Riva
Roberto
R
Tinuper
Paolo
P
Baruzzi
Agostino
A
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*
D000927:Anticonvulsants; D003278:Contraceptives, Oral, Hormonal; D014227:Triazines; D000077213:Lamotrigine