Survey of Anticonvulsant Drugs and Lithium Prescription in Women of Childbearing age in Japan Using a Public National Insurance Claims Database

Abstract

Purpose: Pharmacological treatments with some anticonvulsants, including valproate, and lithium should be avoided where possible in childbearing-aged and pregnant women with epilepsy and bipolar disorder be- cause they increase the risk of major congenital malformations. We surveilled real-world prescriptions of an- ticonvulsants and lithium in childbearing-aged female and male outpatients in Japan, using the first public National Insurance Claims Database of Japan. Methods: We performed a summary statistical analysis of the numbers of the most prescribed 11 anticonvul- sants and lithium tablets in female and male outpatients aged 15-29 (younger childbearing age), 30-49 (older childbearing age), and >50 (non-childbearing age) years from April 2014 to March 2015. We deter- mined the association between anticonvulsant or lithium use and sex at childbearing age, and the odds ratio (OR) and 95% confidence intervals (CIs) were estimated using logistic regression analysis. Results: Valproate (number of tablets = 273,135,937) was the most prescribed among the 12 investigated drugs, and 125,451,907 tablets were prescribed for women (younger, older, and non-childbearing ages, 19,296,528, 47,826,746, and 58,328,63, respectively), compared to 147,684,031 tablets for men (24,534,648, 57,229,981, and 65,919,402, respectively). Valproate prescription was only slightly lower in childbearing- aged women than in the same-aged men (i.e., 15-29 years of age, OR = 0.889 [95% CI, 0.888-0.890]; 30-49 years of age, OR = 0.944 [95% CI, 0.944-0.945]). Discussion: This study demonstrated valproate was highly prescribed for childbearing-aged women in Japan in 2014-2015. Physicians should prescribe valproate with considerable caution in girls and childbearing-aged women.