Valproate effects on kinetics of lamotrigine in pregnancy and treatment with oral contraceptives.
In eight women treated with lamotrigine monotherapy, the lamotrigine dose/plasma concentration (D/C) ratio increased by 295% from baseline outside pregnancy to midgestation, whereas in six women treated with lamotrigine in combination with valproate, the increase was only 60%. No difference in lamotrigine D/C ratio was found between users and nonusers of oral contraceptives comedicated with valproate. Valproate seems to reduce the induction of lamotrigine metabolism associated with pregnancy or use of contraceptives.
Tomson
T
T
Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden. torbjorn.tomson@karolinska.se
Luef
G
G
Sabers
A
A
Pittschieler
S
S
Ohman
I
I
D000927:Anticonvulsants / Q000008:administration & dosage; D003276:Contraceptives, Oral / Q000008:administration & dosage*; D004338:Drug Combinations; D004827:Epilepsy / Q000097:blood / Q000188:drug therapy; D005260:Female; D006801:Humans; D007700:Kinetics; D000077213:Lamotrigine; D008657:Metabolic Clearance Rate / Q000187:drug effects; D011247:Pregnancy / Q000097:blood* / Q000187:drug effects*; D011248:Pregnancy Complications / Q000097:blood / Q000188:drug therapy; D014227:Triazines / Q000008:administration & dosage / Q000097:blood* / Q000493:pharmacokinetics*; D014635:Valproic Acid / Q000008:administration & dosage*
D000927:Anticonvulsants; D003276:Contraceptives, Oral; D004338:Drug Combinations; D014227:Triazines; D014635:Valproic Acid; D000077213:Lamotrigine