Ondansetron, Oral

What are other names for this medicine?

Generic and brand names: ondansetron, oral; Zofran

What is this medicine used for?

This medicine is taken by mouth to prevent nausea and vomiting during cancer chemotherapy, during radiation treatments, and after surgery. It may be prescribed with very strong chemotherapy medicines and for other conditions as determined by your health care provider. It comes in tablet and liquid forms.

What should my health care provider know before I take this medicine?

If you have had an allergic reaction to this medicine in the past, be sure to tell your health care provider.

Females of childbearing age: Tell your health care provider if you are pregnant or breast-feeding.

How do I use it?

To prevent nausea and vomiting during cancer chemotherapy, the usual dosage for children over 12 years of age and adults is one 8-mg tablet (or two 4-mg tablets) or 2 teaspoonfuls (10 mL) of the liquid twice a day. Take the first dose of the day 30 minutes before receiving the chemotherapy and the second dose 8 hours after the first dose. For 1 or 2 days after chemotherapy, your health care provider may want you to take the same dosage every 12 hours. Follow your health care provider's directions exactly.

The usual dosage for children 4 to 11 years old is one 4-mg tablet or 1 teaspoonful of the liquid 3 times a day. Take the first dose of the day 30 minutes before receiving chemotherapy and the other two doses 4 and 8 hours after the first dose. For 1 or 2 days after chemotherapy the health care provider may prescribe the same dosage every 8 hours. Follow your health care provider's directions exactly.

For the prevention of nausea and vomiting caused by radiation in adults, the dosage depends on the extent of the radiation. For prevention of nausea and vomiting after surgery, your health care provider will determine the proper dosage. Follow your health care provider's directions exactly.

If you are not sure of your dosage, ask your health care provider or pharmacist.

What should I watch out for?

If you have an allergic reaction (hives, itching, a rash, trouble breathing or tightness in your chest), contact your health care provider right away or get emergency medical help.

What are the possible side effects?

Along with its needed effects, your medicine may cause some unwanted side effects. Some side effects may be very serious. Some side effects may go away as your body adjusts to the medicine. Tell your health care provider if you have any side effects that continue or get worse.

Serious (report these to your health care provider right away): Hives, itching, a rash, trouble breathing, tightness in your chest.

Other: Headache, sick feeling, tiredness, constipation, diarrhea, dizziness, abdominal pain, dry mouth.

What products might interact with this medicine?

No significant drug interactions have been reported.

The effects of this medicine may be increased if you take it with grapefruit juice. Discuss this with your health care provider.

Keep a list of all your medicines (prescription, nonprescription, supplements, natural remedies, and vitamins) with you. Be sure that you tell all health care providers who treat you about all the products you are taking.

This advisory includes selected information only and may not include all side effects of this medicine or interactions with other medicines. Ask your health care provider or pharmacist for more information or if you have any questions.

Ask your pharmacist for the best way to dispose of outdated medicine or medicine you have not used. Do not throw medicine in the trash.

Keep all medicines out of the reach of children.

Do not share medicines with other people.