Ondansetron ODT 8mg Tablets
It is used to treat or prevent upset stomach and throwing up.
Drug Class
Antiemetic
Pharmacologic Class
Selective 5-HT3 Receptor Antagonist
Pregnancy Category
Not available
FDA Approved
Dec 1990
DEA Schedule
Not Controlled
Overview
What is this medicine?
Ondansetron ODT is a medicine that helps prevent nausea and vomiting. It works by blocking a natural substance in your body (serotonin) that can cause you to feel sick. The ODT form dissolves quickly on your tongue without needing water.
How to Use This Medicine
Taking Your Medication
To use this medication correctly, follow your doctor's instructions and read all the information provided. You can take this medication with or without food. When opening a foil blister pack, do not push the tablet through the foil. Instead, use dry hands to remove the tablet from the foil, and open it immediately before use. Place the tablet on your tongue and let it dissolve. You do not need water, and do not swallow the tablet whole. Additionally, do not chew, break, or crush the tablet.
Storing and Disposing of Your Medication
Store this medication at room temperature, protected from light, and in a dry place. Avoid storing it in a bathroom. Keep all medications in a safe location, out of the reach of children and pets. Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so. If you have questions about disposing of your medication, consult your pharmacist. You may also want to check if there are drug take-back programs in your area.
Missing a Dose
If you take this medication regularly, take a missed dose as soon as you remember. However, if it is close to the time for your next dose, skip the missed dose and resume your normal schedule. Do not take two doses at the same time or take extra doses. If you take this medication as needed, do not take it more frequently than directed by your doctor.
To use this medication correctly, follow your doctor's instructions and read all the information provided. You can take this medication with or without food. When opening a foil blister pack, do not push the tablet through the foil. Instead, use dry hands to remove the tablet from the foil, and open it immediately before use. Place the tablet on your tongue and let it dissolve. You do not need water, and do not swallow the tablet whole. Additionally, do not chew, break, or crush the tablet.
Storing and Disposing of Your Medication
Store this medication at room temperature, protected from light, and in a dry place. Avoid storing it in a bathroom. Keep all medications in a safe location, out of the reach of children and pets. Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so. If you have questions about disposing of your medication, consult your pharmacist. You may also want to check if there are drug take-back programs in your area.
Missing a Dose
If you take this medication regularly, take a missed dose as soon as you remember. However, if it is close to the time for your next dose, skip the missed dose and resume your normal schedule. Do not take two doses at the same time or take extra doses. If you take this medication as needed, do not take it more frequently than directed by your doctor.
Lifestyle & Tips
- Take exactly as prescribed, do not take more than recommended.
- Place the tablet on your tongue, allow it to dissolve, and then swallow. Do not chew or swallow whole.
- Report any signs of irregular heartbeat, dizziness, or fainting immediately.
- Stay hydrated, especially if experiencing vomiting or diarrhea.
- Avoid alcohol as it can worsen nausea and vomiting.
Available Forms & Alternatives
Available Strengths:
- Ondansetron ODT 8mg Tablets
- Ondansetron ODT 4mg Tablets
- Ondansetron 4mg/5ml Solution
- Ondansetron 2mg/ml Inj, 2ml
- Ondansetron 8mg Tablets
- Ondansetron 4mg Tablets
- Ondansetron 8mg Tablets
- Ondansetron 4mg Tablets
- Ondansetron 4mg/2ml Inj, 2ml
- Ondansetron 4mg Tablets
- Ondansetron 40mg/20ml Inj, 20ml
- Ondansetron 4mg/2ml Pf Syr Inj, 2ml
Dosing & Administration
Adult Dosing
Standard Dose:
Varies by indication. For highly emetogenic chemotherapy: 24 mg orally once, 30 minutes before chemotherapy. For moderately emetogenic chemotherapy: 8 mg orally twice daily, first dose 30 minutes before chemotherapy, then 8 hours after, then 8 mg every 12 hours for 1-2 days. For radiation therapy: 8 mg orally 1-2 hours before each fraction. For postoperative nausea/vomiting: 16 mg orally 1 hour before anesthesia.
Dose Range:
8 - 24 mg
Condition-Specific Dosing:
Highly Emetogenic Chemotherapy:
24 mg orally once, 30 minutes before chemotherapy.
Moderately Emetogenic Chemotherapy:
8 mg orally twice daily, first dose 30 minutes before chemotherapy, then 8 hours after, then 8 mg every 12 hours for 1-2 days.
Total Body Irradiation:
8 mg orally 1-2 hours before each fraction of radiation.
Single High-Dose Fraction Radiation:
8 mg orally 1-2 hours before radiation, then 8 mg every 8 hours for 1-2 days after radiation.
Daily Fractionated Radiation:
8 mg orally 1-2 hours before each daily fraction of radiation.
Postoperative Nausea and Vomiting:
16 mg orally 1 hour before induction of anesthesia.
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established (safety and efficacy not established in pediatric patients younger than 6 months of age).
Child:
For chemotherapy-induced nausea and vomiting (CINV) 6 months to <12 years: 4 mg orally 30 minutes before chemotherapy, then 4 and 8 hours after, then 4 mg every 8 hours for 1-2 days. For CINV 12 years and older: Same as adult dosing. For postoperative nausea and vomiting (PONV) 40 kg or less: 4 mg orally 1 hour before anesthesia. For PONV over 40 kg: 8 mg orally 1 hour before anesthesia.
Adolescent:
Same as adult dosing for CINV and PONV.
Dose Adjustments
Renal Impairment:
Mild:
No adjustment needed
Moderate:
No adjustment needed
Severe:
No adjustment needed
Dialysis:
No adjustment needed; Ondansetron is not significantly removed by dialysis.
Hepatic Impairment:
Mild:
No adjustment
Moderate:
No adjustment
Severe:
For severe hepatic impairment (Child-Pugh score ≥10), a single maximum daily dose of 8 mg should not be exceeded.
Pharmacology
Mechanism of Action
Ondansetron is a selective 5-HT3 receptor antagonist. Chemotherapeutic agents and radiation therapy cause release of serotonin (5-HT) from enterochromaffin cells of the small intestine. The released serotonin then activates 5-HT3 receptors located on vagal afferent neurons in the periphery and in the chemoreceptor trigger zone (CTZ) in the area postrema, initiating the vomiting reflex. Ondansetron blocks the action of serotonin at these 5-HT3 receptors, thereby preventing nausea and vomiting.
Pharmacokinetics
Absorption:
Bioavailability:
Approximately 60% (oral)
Tmax:
1.5-2.5 hours
FoodEffect:
Food does not affect the extent of absorption, but may increase Tmax slightly.
Distribution:
Vd:
1.9 L/kg
ProteinBinding:
70-76%
CnssPenetration:
Limited
Elimination:
HalfLife:
3-6 hours (adults), 2.9 hours (pediatric 6-24 months), 2.2 hours (pediatric 3-12 years)
Clearance:
0.3-0.6 L/min
ExcretionRoute:
Renal (5-10% unchanged), Fecal (major route for metabolites)
Unchanged:
5-10%
Pharmacodynamics
OnsetOfAction:
30 minutes to 2 hours (oral)
PeakEffect:
1.5-2.5 hours
DurationOfAction:
4-8 hours (dose-dependent)
Safety & Warnings
Side Effects
Important Side Effects to Report to Your Doctor Immediately
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you experience any of the following symptoms, seek medical attention right away:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Trouble passing urine
Dizziness
Sudden chest pain or tightness
Abnormal heartbeat, including a fast or irregular heartbeat, or if you pass out (this medication can cause a type of abnormal heartbeat called prolonged QT interval, which may lead to another type of unsafe abnormal heartbeat called torsades de pointes)
Serotonin syndrome, a potentially life-threatening condition, which may be more likely to occur if you are taking certain other medications. Symptoms include:
+ Agitation
+ Change in balance
+ Confusion
+ Hallucinations
+ Fever
+ Fast or abnormal heartbeat
+ Flushing
+ Muscle twitching or stiffness
+ Seizures
+ Shivering or shaking
+ Sweating a lot
+ Severe diarrhea
+ Upset stomach or throwing up
+ Very bad headache
Stomach pain or swelling of the stomach area, especially if you have had surgery in the stomach area or have experienced upset stomach and throwing up after chemotherapy (this medication may make it harder to recognize the signs of a bowel block)
Other Possible Side Effects
Like all medications, this drug can cause side effects. Many people experience no side effects or only mild ones. If you experience any of the following side effects, or if they bother you or do not go away, contact your doctor:
Headache
Feeling tired or weak
Diarrhea or constipation
Feeling sleepy
Anxiety
This is not a complete list of possible side effects. If you have questions or concerns about side effects, talk to your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you experience any of the following symptoms, seek medical attention right away:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Trouble passing urine
Dizziness
Sudden chest pain or tightness
Abnormal heartbeat, including a fast or irregular heartbeat, or if you pass out (this medication can cause a type of abnormal heartbeat called prolonged QT interval, which may lead to another type of unsafe abnormal heartbeat called torsades de pointes)
Serotonin syndrome, a potentially life-threatening condition, which may be more likely to occur if you are taking certain other medications. Symptoms include:
+ Agitation
+ Change in balance
+ Confusion
+ Hallucinations
+ Fever
+ Fast or abnormal heartbeat
+ Flushing
+ Muscle twitching or stiffness
+ Seizures
+ Shivering or shaking
+ Sweating a lot
+ Severe diarrhea
+ Upset stomach or throwing up
+ Very bad headache
Stomach pain or swelling of the stomach area, especially if you have had surgery in the stomach area or have experienced upset stomach and throwing up after chemotherapy (this medication may make it harder to recognize the signs of a bowel block)
Other Possible Side Effects
Like all medications, this drug can cause side effects. Many people experience no side effects or only mild ones. If you experience any of the following side effects, or if they bother you or do not go away, contact your doctor:
Headache
Feeling tired or weak
Diarrhea or constipation
Feeling sleepy
Anxiety
This is not a complete list of possible side effects. If you have questions or concerns about side effects, talk to your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Chest pain, shortness of breath, or irregular heartbeat (palpitations)
- Severe dizziness or fainting
- Muscle stiffness, twitching, agitation, confusion, or hallucinations (signs of serotonin syndrome)
- Severe headache
- Severe constipation or abdominal pain
- Rash or allergic reaction (swelling of face, lips, tongue, or throat, difficulty breathing)
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, any of its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction you experienced, including any symptoms that occurred.
If you have a condition known as long QT on an electrocardiogram (ECG).
* If you are currently taking apomorphine.
This list is not exhaustive, and it is crucial to discuss all your medications, including prescription and over-the-counter (OTC) drugs, natural products, and vitamins, with your doctor and pharmacist. They will help you determine if it is safe to take this medication with your existing medications and health conditions.
Remember, do not start, stop, or change the dosage of any medication without first consulting your doctor to ensure your safety.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, any of its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction you experienced, including any symptoms that occurred.
If you have a condition known as long QT on an electrocardiogram (ECG).
* If you are currently taking apomorphine.
This list is not exhaustive, and it is crucial to discuss all your medications, including prescription and over-the-counter (OTC) drugs, natural products, and vitamins, with your doctor and pharmacist. They will help you determine if it is safe to take this medication with your existing medications and health conditions.
Remember, do not start, stop, or change the dosage of any medication without first consulting your doctor to ensure your safety.
Precautions & Cautions
It is essential to inform all of your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. If you have phenylketonuria (PKU), consult with your doctor, as some formulations of this drug may contain phenylalanine. Additionally, if you are pregnant, planning to become pregnant, or are breast-feeding, discuss this with your doctor to carefully weigh the benefits and risks of this medication to both you and your baby.
Overdose Information
Overdose Symptoms:
- Severe constipation
- Hypotension (low blood pressure)
- Vasovagal episode with transient AV block
- Transient blindness
- Serotonin syndrome
- QT interval prolongation, Torsade de Pointes
What to Do:
Seek immediate medical attention. Call 911 or Poison Control at 1-800-222-1222. Treatment is supportive and symptomatic. ECG monitoring is recommended.
Drug Interactions
Contraindicated Interactions
- Apomorphine (concurrent use may cause profound hypotension and loss of consciousness)
Major Interactions
- QT-prolonging drugs (e.g., amiodarone, sotalol, quinidine, procainamide, disopyramide, dofetilide, dronedarone, chlorpromazine, thioridazine, pimozide, ziprasidone, haloperidol, methadone, citalopram, escitalopram, moxifloxacin, erythromycin, pentamidine, tricyclic antidepressants)
- Serotonergic drugs (e.g., SSRIs, SNRIs, MAOIs, tricyclic antidepressants, fentanyl, lithium, tramadol, triptans) - increased risk of serotonin syndrome
Moderate Interactions
- Phenytoin, Carbamazepine, Rifampin (CYP3A4 inducers - may decrease ondansetron levels)
- Tramadol (may reduce analgesic effect of tramadol)
- Dexamethasone (may enhance antiemetic effect of ondansetron)
Minor Interactions
- Not specifically identified as minor, but general caution with drugs affecting GI motility.
Monitoring
Baseline Monitoring
ECG (Electrocardiogram)
Rationale: To assess baseline QT interval, especially in patients with pre-existing cardiac conditions, electrolyte abnormalities, or those taking other QT-prolonging medications.
Timing: Before initiation of therapy, particularly with higher doses or in at-risk patients.
Electrolytes (Potassium, Magnesium)
Rationale: Hypokalemia and hypomagnesemia can increase the risk of QT prolongation.
Timing: Before initiation of therapy, especially in patients at risk for electrolyte imbalances.
Routine Monitoring
ECG (QTc interval)
Frequency: As clinically indicated, especially if new cardiac symptoms develop or if dose is increased.
Target: <450 ms (men), <470 ms (women); adjust based on individual risk factors.
Action Threshold: Discontinue if QTc >500 ms or if there is a significant increase from baseline; correct electrolyte abnormalities.
Bowel movements
Frequency: Daily
Target: Regular bowel habits
Action Threshold: Manage constipation or diarrhea as needed.
Symptom Monitoring
- Headache
- Constipation
- Diarrhea
- Fatigue
- Dizziness
- Arrhythmias (palpitations, syncope)
- Signs of serotonin syndrome (agitation, hallucinations, rapid heart beat, fever, sweating, muscle stiffness, twitching, loss of coordination, nausea, vomiting, diarrhea)
Special Patient Groups
Pregnancy
Risk summary indicates that available data from published epidemiologic studies and postmarketing reports on ondansetron use in pregnant women have not identified a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes. However, some studies suggest a possible small increased risk of oral clefts. Use only if clearly needed.
Trimester-Specific Risks:
First Trimester:
Some observational studies suggest a possible small increased risk of oral clefts (e.g., cleft lip/palate) when used during the first trimester. Data are conflicting and not conclusive.
Second Trimester:
No specific risks identified.
Third Trimester:
No specific risks identified.
Lactation
Ondansetron is present in human milk. There are no data on the effects of ondansetron on the breastfed infant or on milk production. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for ondansetron and any potential adverse effects on the breastfed infant from ondansetron or from the underlying maternal condition. Monitor infant for sedation and gastrointestinal effects (e.g., constipation, diarrhea).
Infant Risk:
L3 (Moderate risk - possible adverse effects on infant; use with caution)
Pediatric Use
Safety and effectiveness have been established for pediatric patients 6 months of age and older for CINV, and for pediatric patients 40 kg or less and over 40 kg for PONV. Dosing is weight-based for younger children. Not recommended for children under 6 months for CINV or under 40 kg for PONV.
Geriatric Use
No dosage adjustment is needed in elderly patients. However, the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy in elderly patients should be considered. QT prolongation risk may be higher in this population.
Clinical Information
Clinical Pearls
- Ondansetron ODT is particularly useful for patients who have difficulty swallowing tablets or who are actively vomiting.
- Ensure patients understand the correct administration of ODT: place on tongue, allow to dissolve, then swallow.
- Be vigilant for QT prolongation, especially in patients with pre-existing cardiac conditions, electrolyte imbalances, or those on other QT-prolonging drugs.
- Counsel patients on the risk of serotonin syndrome when co-administered with other serotonergic agents.
- Constipation is a common side effect; advise on preventative measures like increased fluid intake and fiber.
Alternative Therapies
- Neurokinin-1 (NK1) receptor antagonists (e.g., Aprepitant, Fosaprepitant, Rolapitant, Netupitant/Palonosetron combination)
- Corticosteroids (e.g., Dexamethasone)
- Dopamine receptor antagonists (e.g., Prochlorperazine, Metoclopramide)
- Cannabinoids (e.g., Dronabinol, Nabilone)
- Antihistamines (e.g., Promethazine)
- Benzodiazepines (e.g., Lorazepam - for anticipatory nausea/vomiting)
Cost & Coverage
Average Cost:
Varies, typically $10-$50 per 30 tablets (8mg ODT)
Generic Available:
Yes
Insurance Coverage:
Tier 1 or 2 (Generic)
General Drug Facts
If your symptoms or health issues persist or worsen, it's essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so be sure to check with your pharmacist for more information. If you have any questions or concerns about this medication, don't hesitate to reach out to your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When seeking help, be prepared to provide details about the medication taken, the amount, and the time it happened.