Ondansetron is used to prevent nausea and vomiting that is caused by cancer medicines (chemotherapy) or radiation therapy. It is also used to prevent nausea and vomiting that may occur after surgery. Ondansetron works in the stomach to block the signals to the brain that cause nausea and vomiting.

This medicine is available only with your doctor's prescription.

Take this medicine only as directed by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered.

To use the oral disintegrating tablet:

• Make sure your hands are dry.
• Do not push the tablet through the foil backing of the package. Instead, gently peel back the foil backing and remove the tablet.
• Immediately place the tablet on top of the tongue. The tablet will dissolve in seconds, and you may swallow it with your saliva. You do not need to drink water or other liquid to swallow the tablet.

To use the oral soluble film:

• Make sure your hands are clean and dry before and after using this medicine.
• Fold the pouch along the dotted line to expose the tear notch.
• While still folded, tear the pouch carefully along the edge and remove the film out from the pouch.
• Put the soluble film immediately on top of your tongue where it will dissolve in 4 to 20 seconds. Do not chew or swallow the film whole.
• Once the film is dissolved, you may swallow with or without water.

If you vomit within 30 minutes after using this medicine, take the same amount of medicine again. If vomiting continues, check with your doctor.

This medicine comes with patient instructions. Read and follow these instructions carefully. Ask your doctor if you have any questions.

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

More common

Confusion

dizziness

fast heartbeat

fever

headache

shortness of breath

weakness

Less common

Decrease in the frequency of urination

decrease in the urine volume

difficulty with passing urine (dribbling)

painful urination

Rare

Arm, back, or jaw pain

chest pain or discomfort

chest tightness or heaviness

convulsions

cough

decreased urine

difficulty with breathing

difficulty with swallowing

dry mouth

fast, pounding, or irregular heartbeat or pulse

increased thirst

loss of appetite

loss of bladder control

loss of consciousness

mood changes

muscle pain or cramps

nausea or vomiting

noisy breathing

numbness or tingling in the hands, feet, or lips

puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue

skin rash, hives, or itching

sweating

tightness in the chest

total body jerking

unusual tiredness or weakness

wheezing

Incidence not known

Blurred vision

dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position

fixed position of the eye

heart stops

hoarseness

inability to move the eyes

increased blinking or spasms of the eyelid

large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs

no breathing

no pulse or blood pressure

noisy breathing

pounding heartbeat

slow or irregular breathing

sticking out of the tongue

sweating

trouble with speaking

unconscious

uncontrolled twisting movements of the neck, trunk, arms, or legs

unusual facial expressions

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

Anxiety

difficulty having a bowel movement (stool)

dry mouth

general feeling of discomfort or illness

hyperventilation

irritability

restlessness

shaking

trouble sleeping

Rare

Difficulty with speaking

drooling

loss of balance control

muscle trembling, jerking, or stiffness

shuffling walk

stiffness of the limbs

twisting movements of the body

uncontrolled movements, especially of the face, neck, and back

Incidence not known

Feeling of warmth

hiccups

redness of the face, neck, arms, and occasionally, upper chest

redness of the skin

welts

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Check with your doctor if severe nausea and vomiting continue after leaving the hospital or cancer treatment center.

Do not use this medicine if you are receiving apomorphine (Apokyn®). Using these medicines together may increase risk for more serious problems.

This medicine may cause serious allergic reactions, including anaphylaxis. Anaphylaxis can be life-threatening and requires immediate medical attention. Call your doctor right away if you have a rash, itching, hoarseness, trouble breathing, trouble swallowing, or any swelling of your hands, face, or mouth while you are using this medicine.

Contact your doctor right away if you have any changes to your heart rhythm. You might feel dizzy or faint, or you might have a fast, pounding, or uneven heartbeat. Make sure your doctor knows if you or anyone in your family has ever had a heart rhythm problem such as QT prolongation.

Check with your doctor right away if you start to have pain or swelling in your stomach area. These may be signs of a serious stomach or bowel problem.

This medicine may make you dizzy. Do not drive or do anything else that could be dangerous until you know how this medicine affects you.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.