Zofran (ondansetron) is a prescription medication classified as a 5-HT3 receptor antagonist, specifically developed to manage and prevent nausea and vomiting. It is a cornerstone in therapeutic regimens for patients undergoing chemotherapy, radiation therapy, and surgery. Its mechanism of action targets the serotonin receptors in the brain and gastrointestinal tract, which are primarily responsible for triggering the vomiting reflex. By blocking these signals, Zofran provides a highly effective and targeted approach to controlling emesis, significantly improving patient comfort and quality of life during challenging medical treatments. This product card provides a comprehensive expert overview of its use, benefits, and essential safety information.

Features

• Active pharmaceutical ingredient: Ondansetron Hydrochloride Dihydrate.
• Available in multiple formulations: oral tablets, orally disintegrating tablets, and oral solution for flexible administration.
• Also available in an injectable form for hospital and clinical use.
• Rapid onset of action, typically within 1-2 hours for oral doses.
• Demonstrated high efficacy in preventing acute and delayed chemotherapy-induced nausea and vomiting (CINV).
• Standardized dosing based on clinical indication and patient factors.

Benefits

• Provides rapid and potent control of nausea and vomiting, allowing patients to maintain hydration and nutrition.
• Significantly improves tolerance to emetogenic cancer treatments, enabling adherence to critical chemotherapy regimens.
• Reduces postoperative nausea and vomiting (PONV), facilitating a smoother and more comfortable recovery.
• Offers formulation flexibility (standard tablet, orally disintegrating tablet, liquid) to suit patients who have difficulty swallowing, particularly pediatric or severely nauseated individuals.
• Helps prevent complications associated with persistent vomiting, such as dehydration, electrolyte imbalances, and esophageal tears.

Common use

Zofran is indicated for the prevention of nausea and vomiting associated with highly and moderately emetogenic cancer chemotherapy. It is also approved for the prevention of postoperative nausea and vomiting and for the prevention of nausea and vomiting associated with radiotherapy in patients receiving total body irradiation or single high-dose fractions to the abdomen. Its use is standard in oncology, anesthesiology, and postoperative care settings.

Dosage and direction

Dosage is highly dependent on the emetogenic potential of the chemotherapy regimen or the surgical procedure and must be determined by a healthcare professional.

• Chemotherapy-induced (adults): A common regimen is 24 mg orally administered 30 minutes before the start of single-day highly emetogenic chemotherapy. For moderately emetogenic chemotherapy, 8 mg orally administered 30 minutes before treatment, followed by 8 mg doses 8 hours after the first dose, then 8 mg every 12 hours for 1-2 days after completion of chemotherapy.
• Postoperative (adults): 16 mg orally administered one hour before anesthesia induction.
• Pediatric patients: Dosing is based on body surface area for chemotherapy-induced nausea and vomiting and must be carefully calculated by a physician.
• Administration: Tablets should be swallowed whole with water. Orally disintegrating tablets are placed on the tongue, where they dissolve rapidly and can be swallowed with saliva without water.

Precautions

Patients should inform their doctor of any history of constipation, intestinal obstructions, or abdominal surgery. Zofran should be used with caution in patients with liver impairment, as metabolism may be reduced, necessitating a lower daily dosage. Electrolyte imbalances (e.g., hypokalemia, hypomagnesemia) should be corrected, as they can increase the risk of serious cardiac arrhythmias. Patients should be advised that Zofran is not intended for treatment of nausea and vomiting of unknown origin.

Contraindications

Zofran is contraindicated in patients with known hypersensitivity to ondansetron or any component of the formulation. Concomitant use of apomorphine is contraindicated due to the risk of profound hypotension and loss of consciousness.

Possible side effect

The most commonly reported side effects are headache, constipation, and fatigue. Less frequently, patients may experience dizziness, diarrhea, or a transient, asymptomatic increase in liver transaminases. A serious but rare side effect is QT interval prolongation on the electrocardiogram, which can lead to a type of arrhythmia known as Torsades de Pointes. Any symptoms of irregular heartbeat should be reported to a physician immediately.

Drug interaction

Zofran has the potential to interact with several other medications. Drugs that also prolong the QT interval (e.g., certain antiarrhythmics, antibiotics like erythromycin, antipsychotics) may have an additive effect and increase arrhythmia risk. Phenytoin, carbamazepine, and rifampin may increase the clearance of ondansetron, reducing its plasma concentration and efficacy. Serotonergic drugs (e.g., SSRIs, SNRIs, tramadol) may theoretically increase the risk of serotonin syndrome, though this is rare.

Missed dose

If a dose is missed, it should be taken as soon as it is remembered. However, if it is almost time for the next scheduled dose, the missed dose should be skipped. Patients should not take a double dose to make up for a missed one. The dosing schedule should be resumed with the next regular dose.

Overdose

Symptoms of overdose may include sudden visual loss, severe constipation, hypotension, and syncope. In cases of suspected overdose, immediate medical attention should be sought. There is no specific antidote for ondansetron overdose; treatment consists of supportive care and management of symptoms, with close monitoring of electrocardiographic parameters for QT prolongation.

Storage

Zofran tablets and oral solution should be stored at controlled room temperature, 20°C to 25°C (68°F to 77°F), in a tightly closed container. The medication must be kept out of reach of children and protected from light and moisture. The orally disintegrating tablets should be kept in their blister package until immediately before use.

Disclaimer

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or medication. Never disregard professional medical advice or delay in seeking it because of something you have read here. The information provided may not cover all possible uses, directions, precautions, drug interactions, or adverse effects.

Reviews

“Zofran was integral to my ability to complete my chemotherapy regimen. The nausea was debilitating with previous antiemetics, but switching to Zofran made a night-and-day difference. I was finally able to keep food and fluids down.” – M.B., Oncology Patient

“As an anesthesiologist, I rely on Zofran as a first-line prophylactic agent for patients at high risk for PONV. Its efficacy profile and safety make it a dependable choice in our enhanced recovery after surgery (ERAS) protocols.” – Dr. A. Sharma, MD

“The orally disintegrating formulation has been a game-changer for our pediatric patients and those who are severely nauseated and cannot swallow a pill. It provides effective relief without the struggle of administration.” – Oncology Nurse Practitioner