Key takeaways
Ondansetron (Zofran) and promethazine (Phenergan) are both used to treat nausea and vomiting, but they work in different ways and have different uses. Ondansetron is an antiemetic that blocks serotonin in the brain, while promethazine is an antihistamine that also blocks dopamine and acetylcholine. Ondansetron is often used after surgery or cancer treatments, and it comes in various forms like tablets, dissolvable tablets, and injections. Promethazine, on the other hand, is used for a wider range of conditions, including allergies, motion sickness, and as a sedative before surgery. It is available as tablets, syrup, suppositories, and injections. Ondansetron can be used in children as young as 4 years old, while promethazine should not be given to children under 2 years old due to the risk of serious breathing problems. Both medications can cause drowsiness, but promethazine has a higher risk of causing excessive sleepiness and other side effects like dizziness and confusion.
