This medication is used to prevent and treat nausea and vomiting. Ondansetron is in a class of medications called serotonin 5-HT3 receptor antagonists. It works by blocking the action of serotonin, a natural substance that may cause nausea and vomiting.

Famotidine belongs to a class of drugs known as H2 blockers. It works by decreasing the amount of acid your stomach produces. It relieves symptoms such as cough that doesn't go away, stomach pain, heartburn, gastritis, and other conditions in which acid backs up from the stomach into the esophagus, causing heartburn.