What patient counseling information should be provided to a patient receiving ondansetron (Zofran) for nausea and vomiting?

Patient Information for Ondansetron (Zofran) for Nausea and Vomiting

Ondansetron is a highly effective medication that prevents nausea and vomiting by blocking serotonin receptors in your body, and you should take it exactly as prescribed—typically 30 minutes before chemotherapy or 1-2 hours before radiation therapy. 1

How to Take Your Medication

Orally Disintegrating Tablets (ODT)

• Do not remove the tablet from the blister pack or bottle until you are ready to take it 1
• With completely dry hands, peel back the paper backing of one blister or remove from bottle 1
• Gently push the tablet through the foil and remove it 1
• Immediately place the tablet on top of your tongue where it will dissolve in seconds 1
• Swallow with your saliva—you do not need water 1

Standard Tablets

• Can be taken with or without food 1
• Taking the medication before bedtime may help reduce nausea 2

Dosing Based on Your Treatment

For Chemotherapy-Induced Nausea and Vomiting

High-risk chemotherapy (like cisplatin):

• Take 24 mg (three 8 mg tablets) 30 minutes before chemotherapy starts 1
• This is a single-day dose only 1

Moderate-risk chemotherapy:

• Take 8 mg 30 minutes before chemotherapy 1
• Take another 8 mg dose 8 hours after the first dose 1
• Continue taking 8 mg twice daily (every 12 hours) for 1-2 days after chemotherapy ends 1

For Radiation Therapy

Total body irradiation:

• Take 8 mg 1-2 hours before each radiation session 1

Single high-dose abdominal radiation:

• Take 8 mg 1-2 hours before radiation 1
• Continue taking 8 mg every 8 hours for 1-2 days after completion 1

Daily fractionated abdominal radiation:

• Take 8 mg 1-2 hours before each radiation session 1
• Continue taking 8 mg every 8 hours on each day you receive radiation 1

For Surgery-Related Nausea

• Take 16 mg (two 8 mg tablets) 1 hour before anesthesia 1

What to Expect

Effectiveness

• Ondansetron works better at preventing vomiting than nausea—you may still feel some nausea even if you don't vomit 3, 4
• The medication typically reduces nausea scores by about 4 points on a 10-point scale 5
• In clinical studies, 96-98% of patients receiving ondansetron had no vomiting episodes 4
• The intravenous form works slightly faster than oral forms, but oral tablets are highly effective 5

When It Starts Working

• Oral tablets begin working within 30 minutes to 2 hours 1
• The orally disintegrating tablets may work slightly faster since they dissolve immediately 1

Possible Side Effects

Common Side Effects

• Headache (occurs in about 3 out of 100 patients) 3
• Elevated liver enzymes (occurs in about 3 out of 100 patients, usually temporary) 3, 4
• Fatigue (occurs in about 4 out of 100 patients) 4
• Constipation 1

Important Safety Information

Heart rhythm concerns:

• Ondansetron can prolong the QT interval on your heart rhythm, particularly at high doses (32 mg IV) 6
• Tell your doctor if you have any heart rhythm problems or take medications that affect heart rhythm 6

Do not use ondansetron if:

• You are taking apomorphine (for Parkinson's disease)—this combination can cause severe low blood pressure and loss of consciousness 1

Special considerations:

• If you have phenylketonuria (PKU): Each 4 mg orally disintegrating tablet contains 3.93 mg phenylalanine; each 8 mg tablet contains 7.86 mg phenylalanine 1
• If you have severe liver disease: Your doctor may limit your dose to 8 mg per day 1
• If you have kidney disease: No dose adjustment is typically needed, but inform your doctor 1

When to Contact Your Doctor

Call your doctor if:

• You continue to vomit despite taking ondansetron—alternative medications can be added 7, 8
• You develop severe abdominal pain or distension (ondansetron does not stimulate bowel movement and may mask intestinal blockage) 1
• You experience irregular heartbeat, dizziness, or fainting 6
• You develop a rash, itching, or difficulty breathing 5

Drug Interactions

Tell your doctor if you take:

• Phenytoin, carbamazepine, or rifampin (these may reduce ondansetron effectiveness) 1
• Tramadol (ondansetron may reduce tramadol's pain-relieving effects) 1
• Any medications that affect heart rhythm 6

Additional Tips for Managing Nausea

• Take ondansetron before you feel nauseated—it works best as prevention rather than treatment 1
• If breakthrough nausea occurs despite ondansetron, contact your healthcare team within 48 hours if hospitalized or within 1 month if outpatient 7
• Your doctor may add other medications like dexamethasone or lorazepam for better control 9, 10
• Taking the medication with food or at bedtime may help reduce nausea as a side effect 2

Storage

• Keep tablets in their original packaging until ready to use 1
• Store at room temperature away from moisture 1
• Keep out of reach of children 1