8 weeks pregnant with third baby with extreme vomiting. Have zofran (ondansetron) 8 mg. What's the correct dose to take for pregnancy? Exhausted all other options

Talk to your OB. Zofran (ondansetron) is dosed one every 12-24 hours but if your vomiting is that severe talk to your OB. Adequate nutrition is absolutely essential for a healthy baby and mom and at times hyperalimentation can be necessary. You also want to be sure that there isn't something else going on causing the nausea. Hope this helps and you are feeling better soon.