Antiepileptic drug use by pregnant women enrolled in Florida Medicaid

Abstract

Objective: The study aims were to investigate secular trends in antiepileptic drug (AED) use in women during pregnancy, and to compare the use of first- and second-generation AEDs.

Methods: Study participants consisted of female Florida Medicaid beneficiaries, older than 15 years, and pregnant within the time period 1999 to 2009. Fifteen AEDs were categorized into first and second generation of AEDs. Continuous use of AEDs was defined as at least 2 consecutive AED prescriptions totaling more than a 30-day supply. Polytherapy was defined as 2 or more AEDs continuously used for at least 30 overlapping days. Annual prevalence was estimated and compared.

Results: We included 2,099 pregnant women who were enrolled in Florida Medicaid from 1999 to 2009 and exposed to AEDs during pregnancy. Although there were fluctuations, overall AED use in the study cohort did not increase from 2000 to 2009 (β ± standard error [SE]: -0.07 ± 0.06, p = 0.31). The use of first-generation AEDs decreased (β ± SE: -6.21 ± 0.47, p < 0.0001), whereas the use of second-generation AEDs increased (β ± SE: 6.27 ± 0.52, p < 0.0001) from 2000 to 2009. AED use in polytherapy did not change through the study period. Valproate use reduced from 23% to 8% in the study population (β ± SE: -1.61 ± 0.36, p = 0.0019), but this decrease was only for women receiving an AED for epilepsy and was not present for other indications.

Conclusion: The second-generation AEDs are replacing first-generation AEDs in both monotherapy and polytherapy. Valproate use has declined for epilepsy but not other indications. Additional changes in AED use are expected in future years.

Figure 1. Percentage of AED use in pregnant women in Florida Medicaid

β = 0.07, SE = 0.06, p = 0.31. AED = antiepileptic drug.

Figure 2. Percentage of first- and second-generation AED use from 2000 to 2009

β = −6.21, SE = 0.47, p < 0.0001 for first-generation AED use; β = 6.27, SE = 0.52, p < 0.0001 for second-generation AED use. AED = antiepileptic drug.

Figure 3. Percentage of most frequently used first- and second-generation AEDs

(A) First-generation AEDs from 2000 to 2009: β = −1.17, SE = 0.34, p = 0.009 for carbamazepine use; β = −2.97, SE = 0.29, p < 0.0001 for phenytoin use; β = −1.61, SE = 0.36, p = 0.0019 for valproate use; and β = −1.13, SE = 0.24, p = 0.0015 for phenobarbital use. (B) Second-generation AEDs from 2000 to 2009: β = 3.48, SE = 0.51, p = 0.0001 for lamotrigine use; β = 2.48, SE = 0.28, p < 0.0001 for levetiracetam use; and β = 0.31, SE = 0.97, p = 0.36 for topiramate use. AED = antiepileptic drug.

Figure 4. Percentage of valproate use in overall study cohort or patients with different indications

β = −1.61, SE = 0.36, p = 0.002 for VPA use in overall study cohort; β = −3.65, SE = 0.95, p = 0.005 for VPA use in patients with epilepsy; β = 0.67, SE = 1.66, p = 0.70 for VPA use in patients with psychiatric disorders only. AED = antiepileptic drug; VPA = valproate.