What is the treatment and management plan for a patient experiencing nausea and vomiting, including dosage and administration of Zofran (ondansetron) and when to seek emergency medical attention?

Patient Information for Zofran (Ondansetron) for Nausea and Vomiting

How to Take Your Zofran

Take Zofran 4-8 mg by mouth every 8 hours as needed for nausea or vomiting. 1, 2 If you have severe liver disease, do not exceed 8 mg total in 24 hours. 2

• Timing: Take the first dose 30 minutes before you expect nausea to start, or as soon as nausea begins 2
• Forms available: Regular tablets or dissolving tablets (ODT) that melt on your tongue—both work equally well 3
• If nausea persists: After taking Zofran as needed for several days without relief, switch to taking it on a scheduled basis (every 8 hours around the clock) for one week, then return to as-needed dosing 1, 4

What to Expect

• Effectiveness: Most patients experience a reduction in nausea severity by 3-4 points on a 10-point scale within 30-60 minutes 5, 3
• Vomiting: About 60% of patients who are vomiting will stop vomiting after taking Zofran 5
• Duration: The medication works for approximately 8 hours 2

Important Side Effects to Monitor

Constipation is the most common side effect and can paradoxically worsen your nausea. 1, 4, 6

• Drink plenty of fluids and consider a stool softener if you become constipated 4
• Headache occurs in some patients but is usually mild 6
• Rare but serious: Stop taking Zofran and call 911 if you experience irregular heartbeat, chest pain, or fainting 2, 7

When to Seek Emergency Care Immediately

Go to the emergency room or call 911 if you experience any of the following:

• Severe dehydration signs: Unable to keep down any liquids for 12+ hours, dark urine or no urination for 8+ hours, extreme dizziness when standing, confusion 1
• Signs of serious underlying conditions: Severe abdominal pain (especially if constant or worsening), blood in vomit (red or coffee-ground appearance), high fever (>101.5°F), severe headache with stiff neck 1
• Medication reaction: Difficulty breathing, throat swelling, severe rash or hives, chest pain, irregular heartbeat 2
• Bowel obstruction symptoms: Complete inability to pass gas or stool combined with severe abdominal distension and vomiting 1

When to Contact Your Doctor (Non-Emergency)

Call your doctor within 24-48 hours if:

• Nausea and vomiting persist despite taking Zofran regularly for 2-3 days 1
• You develop severe constipation that doesn't improve with over-the-counter remedies 4
• You experience persistent headaches after taking the medication 6
• Your symptoms improve but then return after stopping the medication 1

What If Zofran Doesn't Work?

If Zofran fails to control your symptoms after 48 hours of scheduled dosing, your doctor may add or switch to alternative medications such as prochlorperazine 5-10 mg, metoclopramide 10 mg, or haloperidol 0.5-2 mg. 1, 4 Do not simply increase your Zofran dose or take it more frequently without consulting your doctor. 4

Special Precautions

• Drug interactions: Tell your doctor if you take medications that affect heart rhythm, including certain antibiotics, antifungals, or psychiatric medications 2, 7
• Pregnancy/breastfeeding: Discuss with your doctor, though Zofran is commonly used in pregnancy 2
• Elderly patients: You may need a lower starting dose (4 mg instead of 8 mg) due to increased sensitivity 4
• Avoid alcohol: Alcohol can worsen nausea and interact with Zofran 2

Common Pitfall to Avoid

Do not assume Zofran will work for all types of nausea. If your nausea is primarily caused by anxiety, constipation, or certain other conditions, Zofran may not be effective and alternative treatments targeting the underlying cause are needed. 4, 8 Contact your doctor if symptoms don't improve within 48 hours of starting treatment. 1