Assalamu alaikum,

If the medication is truly this needed to be taken in such interval, this is permissible.

However, I very much doubt that you can’t take it at sunset and before the break of dawn only in Ramadan. Check with another doctor.

I am on medication I have to take every 12hrs, the doctor says its a lifetime medication. I cant fast ramadan because the hours of fasting are 17. Can I make ramadan up durning the winter hrs when the days are short enough?