LAMOTRIGINE CONCENTRATIONS ACROSS THE MENSTRUAL CYCLE IN WOMEN WITH CATAMENIAL EPILEPSY
Abstract number :
1.328
Submission category :
Year :
2004
Submission ID :
4356
Source :
www.aesnet.org
Presentation date :
12/2/2004 12:00:00 AM
Published date :
Dec 1, 2004, 06:00 AM
Authors :
Silvia B. Neme, and Nancy R. Foldvary-Schaefer
An estimated 2/3rd of women with epilepsy have seizure exacerbations in association with the menstrual cycle, a condition known as catamenial epilepsy. Seizure exacerbations during the days prior to menstruation have been attributed to the abrupt withdrawal of progesterone metabolites that have anticonvulsant properties. The preovulatory exacerbation has been attributed to the midcycle surge of estrogen, a proconvulsant. The relationship between catamenial seizure exacerbation and antiepileptic drug (AED) serum concentrations is unknown. We report preliminary data on changes in lamotrigine (LTG) concentrations across the menstrual cycle in women with catamenial epilepsy. Participants are part of an IRB-approved study investigating the efficacy of progesterone for the treatment of catamenial seizures. All women in this study had the perimenstrual pattern (C1) of seizure exacerbation described by Herzog et al. This was defined as a two-fold or greater increase in seizures during the perimenstrual (M phase; days -3 to +3) compared to the midfollicular (F phase;days +4 to + 9) and midluteal (L phase; days -12 to -4) phases in ovulatory cycles. Ovulation was documented by urinary LH and midluteal progesterone [gt] 5 ng/ml. LTG concentrations were obtained during each phase for two consecutive cycles during which AED therapy remained constant. Average daily seizure frequency (ADSF) during each phase was calculated and correlated with LTG concentrations. Complete data were available for 7 cycles in 4 women (1 LTG monotherapy; 3 on combination therapy with phenytoin topiramate and valproic acid). ADSF was significantly greater during M phase: 0.31 (0.16-0.42) compared to F: 0.07 (0-0.33); O: 0.11(0-0.33); and L: 0.09 (0-0.44). Mean LTG for M: 5.2 ug/ml (3.1 -14); O: 7.6 ug/ml (5.0 -19.1); and L: 5.3 ug/ml (2.8 -17). Overall, there was a 31% reduction in LTG concentrations during M phase compared to O and 1% reduction during M phase compared to L phase.(Figure1).[figure1] Alterations in AED pharmacokinetics may play a role in seizure expression surrounding menses in some women with epilepsy. Herzog AG, Klein P, Ransil BJ. Three patterns of catamenial epilepsy. Epilepsia 1997; 38(10): 1082-1088
