Buying medicine for epilepsy in Japan

Hello, i have epilepsy and use a medicine called Topamax 200mg.

I was curious how do i buy this in Japan when i come there as an international student? Do health insurance cover any percentage of this? I'm scared that it will be expensive because it is expensive here in my country but insurance pays most of it.

If You want to buy medicine in japan,youmust
join japan health insurance programme then you will pay 30% of total cost and remaining 70% provided by japanese government

Actually joining health insurance in Japan is mandatory.
You will need to go to a doctor in Japan to get a new prescription. So best probably to bring a supply for 1 month and arrange for your a doctor visit as soon as you arrive so you can get your refill.
You university may have some assistance programm to explain Japanese health insurance and health system. Just ask them.