For those who took zofran for vommiting, What mg were y'all taking?

I take phenegrin

4mg didn't work so they switch to phenegrin

I started with 4mg but it's not helping so one of my doctors nurses prescribed me 8mg of it now but I went to the pharmacy to pick it up and they said my insurance refuses to cover it bc it's too high of a dosage and goes over max daily dosage and bc I got some not too long ago. It's only 20 without insurance but idk if I feel comfortable taking the higher dosage now

4 MG