Key takeaways
Dimenhydrinate (Dramamine) and ondansetron (Zofran) can both be used to prevent nausea and vomiting, but they belong to different medication classes. Dimenhydrinate is an antihistamine and anticholinergic, while ondansetron is an antiemetic that works by blocking serotonin. Dimenhydrinate is available over-the-counter in forms like tablets, chewable tablets, and syrup, and is typically taken every 4 to 6 hours. Ondansetron, on the other hand, is a prescription medication available as tablets, orally disintegrating tablets, and liquid, and is usually taken every 8 to 12 hours. Dimenhydrinate can cause drowsiness, dizziness, and constipation, while ondansetron may lead to headaches, fatigue, and either constipation or diarrhea. Dimenhydrinate is not recommended for people with glaucoma or urinary problems, and it can interact with other antihistamines. Ondansetron can interact with medications that affect serotonin levels and may cause serious heart rhythm problems
