I started her on anti-seizure medication.
【翻译】我开始给她服用抗癫痫药物。

start sb. on + 某种药物：习语。意思是“医生开始在病人身上用药”。又如：

That didn't work, so the next day she saw a doctor, who started her on an antibiotic and a painkiller.
这并没有起作用，第二天她看了医生，医生给她开了抗生素和止痛药。