Which medication is primarily used to treat nausea and vomiting?

The medication primarily used to treat nausea and vomiting is ondansetron. It belongs to a class of drugs known as 5-HT3 receptor antagonists, which work by blocking the action of serotonin, a neurotransmitter that can trigger nausea and vomiting when it binds to its receptors in the central nervous system and gastrointestinal tract. Ondansetron is commonly used to prevent nausea and vomiting caused by chemotherapy, radiation therapy, and surgery.

Ranitidine, on the other hand, is used primarily to reduce stomach acid and treat conditions like gastroesophageal reflux disease (GERD) and peptic ulcers. Loperamide is an antidiarrheal medication that slows gut movement, thus is not useful for nausea and vomiting. Docusate sodium is a stool softener used to prevent or treat constipation, making it unrelated to the treatment of nausea. Understanding the specific uses of these medications highlights why ondansetron is the most appropriate choice for managing nausea and vomiting.