Key takeaways
Promethazine (Phenergan) and Palonosetron (Aloxi) are both used to treat nausea and vomiting, but they work differently and have different uses. Promethazine is an antihistamine that also blocks dopamine and acetylcholine, making it useful for allergies, motion sickness, and pre-surgery relaxation. It comes in various forms, including tablets, syrup, suppositories, and injections. Palonosetron, on the other hand, is a serotonin antagonist specifically used to prevent nausea and vomiting from chemotherapy and surgery. It is only available as an injection and must be administered by a healthcare professional. Promethazine can cause drowsiness and dizziness, while Palonosetron's common side effects include headache and constipation. Promethazine is not recommended for children under 2 years old due to serious breathing risks, whereas Palonosetron can be used in children as young as 1 month for chemotherapy-related nausea.
