SN instructed patient / caregiver on Zofran - ondansetron. This medication blocks the actions of chemicals in the body that can trigger nausea and vomiting. Zofran is used to prevent nausea and vomiting that may be caused by surgery, cancer chemotherapy, or radiation treatment. Serious side effects include blurred vision or temporary vision loss ( lasting from only a few minutes to several hours ), slow heart rate, trouble breathing, anxiety, agitation, shivering, feeling like you might pass out, and urinating less than usual or not at all. Stop taking Zofran and call your doctor at once if you have any of these side effects. Ondansetron may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert. Zofran side effects get emergency medical help if you have signs of an allergic reaction to Zofran: rash, hives, fever, chills, difficult breathing, swelling of your face, lips, tongue, or throat. Call your doctor at once if you have: severe constipation, stomach pain, or bloating, headache with chest pain and severe dizziness, fainting, fast or pounding heartbeats, fast or pounding heartbeats, jaundice ( yellowing of the skin or eyes ); blurred vision or temporary vision loss ( lasting from only a few minutes to several hours ); high levels of serotonin in the body - agitation, hallucinations, fever, fast heart rate, overactive reflexes, nausea, vomiting, diarrhea, loss of coordination, fainting. Patient / caregiver verbalized understanding. Instruct to call agency for questions or concerns.