title: Oral contraceptives reduce lamotrigine plasma levels.
abstract: The mean steady-state plasma concentration of lamotrigine (LTG) was 13 micro mol/L in 22 women taking LTG in combination oral contraceptives (OC) compared with 28 micro mol/L among 30 women on LTG who did not take OC (p < 0.0001). The LTG dose/body weight/plasma concentration was 2.1 L/kg/day in women on OC compared with 0.8 L/kg/day in women without OC (p < 0.0001), indicating that LTG plasma levels are reduced by >50% during OC co-medication. It is advisable to monitor LTG plasma levels in conjunction with initiation or withdrawal of OC in women on LTG therapy.
authors.affiliation: Danish Epilepsy Hospital, University of Aarhus, Denmark. anns@glostruphosp.kbhamt.dk
authors.forename: Anne
authors.initials: A
authors.lastname: Sabers
authors.forename: Inger
authors.initials: I
authors.lastname: Ohman
authors.forename: Jakob
authors.initials: J
authors.lastname: Christensen
authors.forename: Torbjörn
authors.initials: T
authors.lastname: Tomson
mesh_terms: D000293:Adolescent; D000328:Adult; D000927:Anticonvulsants / Q000097:blood* / Q000493:pharmacokinetics; D003277:Contraceptives, Oral, Combined / Q000494:pharmacology*; D003278:Contraceptives, Oral, Hormonal / Q000494:pharmacology*; D003718:Denmark; D004347:Drug Interactions; D005260:Female; D014453:Glucuronosyltransferase / Q000378:metabolism; D006801:Humans; D008658:Inactivation, Metabolic; D000077213:Lamotrigine; D008297:Male; D012189:Retrospective Studies; D013548:Sweden; D014227:Triazines / Q000097:blood* / Q000493:pharmacokinetics
chemical_list: D000927:Anticonvulsants; D003277:Contraceptives, Oral, Combined; D003278:Contraceptives, Oral, Hormonal; D014227:Triazines; C019787:bilirubin glucuronoside glucuronosyltransferase; D014453:Glucuronosyltransferase; D000077213:Lamotrigine