I have an attack of diverticulitis. Taking metronidazole and cipro (ciprofloxacin). The nausea is killing me and I wanted to know if I could take Zofran or bonine?

Nausea. Most likely the Metronidazole is the culprit. Try to take the medicine after eating something. Zofran (ondansetron) may help as well.
Prescriptions. Anti emetics like phenergan, (promethazine) and zofran need a prescription. Okay to call your doc and make this request. If you are vomiting, get evaluated. If you are not vomiting and no fever, okay to try tea, broth, juices in small frequent amounts.