Too much zofran?

Nova

I finally got my doctor to get me a prescription after trying ginger, unisom, and B12. But now I’m nervous about taking it. I can definitely tell when it wears off so I feel like I need to take 2 a day which technically follows the prescribed way to take it.

I’m just curious if I should try to tough it out when I can? Can you take too much zofran? Is there a reason doctors don’t prescribe it more?