Key takeaways
Promethazine (Phenergan) and dolasetron (Anzemet) are both prescription medications used to treat nausea and vomiting, but they have some important differences. Promethazine is an antihistamine and anticholinergic that also blocks dopamine, while dolasetron is an antiemetic that works by blocking serotonin. Promethazine is used for a variety of conditions, including nausea, motion sickness, and allergy symptoms, and is available in multiple forms such as tablets, oral solution, suppositories, and injections. Dolasetron is specifically FDA-approved for preventing nausea and vomiting caused by chemotherapy and is only available as an oral tablet. Promethazine is available as a lower-cost generic, while dolasetron is only available as a brand-name medication. Common side effects of promethazine include drowsiness and dizziness, whereas dolasetron can cause headaches and fatigue. Promethazine can interact with medications like MAOIs, while dolasetron can affect heart rhythm and serotonin levels.
