Ondansetron 4mg
Generic For: Zofran
Ondansetron 4mg (brand name Zofran) is a prescription anti-nausea tablet in the 5-HT3 receptor antagonist class. It is used to prevent nausea and vomiting caused by chemotherapy, radiation therapy, and surgery. After a licensed provider reviews your prescription, your order ships from a licensed U.S. pharmacy.
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Ondansetron (Zofran) is a 5-HT3 antagonist antiemetic used to prevent nausea and vomiting from chemotherapy, radiation therapy, and surgery.
Ondansetron 4mg Quick Facts
| Drug class | 5-HT3 receptor antagonist |
|---|---|
| Treats | Chemotherapy-induced nausea, radiation-induced nausea, post-surgery nausea and vomiting |
| Form | Tablet |
| Typical dosing | Take 1 tablet by mouth every 4 to 6 hours as needed for nausea. If nausea occurs with food or pills, take 1 tablet 30 minutes before. |
| Prescription required | Yes — prescription only |
What Is Ondansetron 4mg?
Ondansetron is a prescription medication known by the brand name Zofran. It belongs to a class of drugs called 5-HT3 receptor antagonists, which work by blocking serotonin signals in the gut and brain that trigger nausea and vomiting. Ondansetron 4mg tablets are FDA-approved to prevent nausea and vomiting caused by cancer chemotherapy, radiation therapy, and surgery. It does not treat the underlying cause of nausea and is taken on a schedule around treatment or surgery as directed by a provider.
What Does Ondansetron 4mg Treat?
Prevention of nausea and vomiting from moderately emetogenic chemotherapy
Prevention of nausea and vomiting from highly emetogenic chemotherapy
Prevention of nausea and vomiting from radiation therapy
Prevention of postoperative nausea and vomiting
Prevention of nausea from total body irradiation
Prevention of nausea from single high-dose radiotherapy to the abdomen
Ondansetron 4mg Dosage
Chemotherapy (moderately emetogenic): 8 mg PO 30 minutes before chemo, then 8 mg 8 hours later; then 8 mg PO every 12 hours for 1-2 days after chemo
Radiation therapy: 8 mg PO 1-2 hours before each fraction of radiotherapy
Postoperative: 16 mg PO 1 hour before induction of anesthesia
Your prescriber will determine the dose and duration that are right for you. Always follow the directions on your prescription label.
Ondansetron 4mg Side Effects
Common side effects
- Headache
- Constipation
- Diarrhea
- Fatigue or drowsiness
- Dizziness
- Fever
- Malaise
Serious side effects
Stop taking this medication and seek medical attention right away if you experience:
- QT prolongation and abnormal heart rhythms (torsade de pointes)
- Serotonin syndrome (agitation, rapid heart rate, fever, muscle rigidity)
- Severe allergic reactions, including anaphylaxis
- Masking of progressive ileus or gastric distension after abdominal surgery
Warnings & Interactions
Do not use with apomorphine (risk of severe low blood pressure and loss of consciousness)
Contraindicated in patients with known hypersensitivity to ondansetron
Can prolong the QT interval; avoid in congenital long QT syndrome
Use caution with other QT-prolonging drugs and in patients with electrolyte abnormalities
Risk of serotonin syndrome when combined with serotonergic drugs (e.g., SSRIs, SNRIs, MAOIs)
May mask symptoms of bowel obstruction after abdominal surgery
Dose adjustment needed in severe hepatic impairment (max 8 mg/day)
Tell your prescriber about all medications, supplements, and health conditions before starting ondansetron 4mg.
Sources & References
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