Ondansetron ODT 4mg 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
Jan 1991
DEA Schedule
Not Controlled
Overview
What is this medicine?
Ondansetron ODT is a medication 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 (Orally Disintegrating Tablet) 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 taking. 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 regular 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 taking. 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 regular 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 by your doctor, usually before chemotherapy, radiation, or surgery.
- Do not take more than the prescribed dose, especially if you have heart problems or are taking other medications that affect your heart rhythm.
- Report any signs of an irregular heartbeat (e.g., dizziness, fainting, fast heartbeat) to your doctor 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
Dose Range:
4 - 24 mg
Condition-Specific Dosing:
Chemotherapy-induced nausea and vomiting (CINV) - highly emetogenic:
24 mg orally once, 30 minutes prior to chemotherapy.
Chemotherapy-induced nausea and vomiting (CINV) - moderately emetogenic:
8 mg orally twice daily (first dose 30 minutes prior to chemotherapy, then 8 hours after first dose, then 8 mg twice daily for 1-2 days after chemotherapy).
Radiation-induced nausea and vomiting (RINV) - total body irradiation:
8 mg orally 1-2 hours prior to each fraction of radiation.
Radiation-induced nausea and vomiting (RINV) - single high-dose fraction:
8 mg orally 1-2 hours prior to radiation, then 8 mg 8 hours after first dose, then 8 mg twice daily for 1-2 days after radiation.
Postoperative nausea and vomiting (PONV):
16 mg orally as a single dose 1 hour prior to 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:
CINV (6 months to <12 years): 4 mg orally 3 times daily (first dose 30 minutes prior to chemotherapy, then 4 and 8 hours after first dose, then 4 mg 3 times daily for 1-2 days after chemotherapy). PONV (1 month to <12 years, >40 kg): 4 mg orally as a single dose 1 hour prior to induction of anesthesia. PONV (1 month to <12 years, <=40 kg): 4 mg orally as a single dose 1 hour prior to induction of anesthesia.
Adolescent:
CINV (>=12 years): Same as adult dosing. PONV (>=12 years): Same as adult dosing.
Dose Adjustments
Renal Impairment:
Mild:
No dosage adjustment necessary.
Moderate:
No dosage adjustment necessary.
Severe:
No dosage adjustment necessary.
Dialysis:
No dosage adjustment necessary; ondansetron is not significantly removed by dialysis.
Hepatic Impairment:
Mild:
No dosage adjustment necessary.
Moderate:
Maximum daily dose of 8 mg in patients with moderate to severe hepatic impairment.
Severe:
Maximum daily dose of 8 mg in patients with moderate to severe hepatic impairment.
Pharmacology
Mechanism of Action
Ondansetron is a selective 5-HT3 receptor antagonist. Serotonin 5-HT3 receptors are located peripherally on vagal nerve terminals and centrally in the chemoreceptor trigger zone (CTZ). Chemotherapeutic agents and radiation therapy cause release of serotonin from enterochromaffin cells of the small intestine, which then stimulates 5-HT3 receptors, initiating the vomiting reflex. Ondansetron blocks this action, thereby preventing nausea and vomiting.
Pharmacokinetics
Absorption:
Bioavailability:
Approximately 60% (oral)
Tmax:
1.5-2 hours
FoodEffect:
Food does not affect the extent of absorption, but may slightly increase Tmax.
Distribution:
Vd:
1.9 L/kg
ProteinBinding:
70-76%
CnssPenetration:
Limited
Elimination:
HalfLife:
3-6 hours (adults), 2.9 hours (pediatric 6-24 months), 3.1 hours (pediatric 3-12 years)
Clearance:
0.38 L/min
ExcretionRoute:
Renal (5% unchanged), Fecal
Unchanged:
Approximately 5%
Pharmacodynamics
OnsetOfAction:
30 minutes (oral)
PeakEffect:
1.5-2 hours
DurationOfAction:
4-8 hours
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
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 severe and 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 vomiting
+ 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 vomiting 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 may not experience any side effects or may only have minor ones. If you are bothered by any of the following side effects or if they do not go away, contact your doctor or seek medical help:
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, contact 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 notice any of the following symptoms, contact your doctor or seek immediate medical attention:
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 severe and 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 vomiting
+ 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 vomiting 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 may not experience any side effects or may only have minor ones. If you are bothered by any of the following side effects or if they do not go away, contact your doctor or seek medical help:
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, contact 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:
- Severe dizziness or fainting (may indicate QT prolongation)
- Fast or irregular heartbeat (palpitations)
- Muscle stiffness or twitching, agitation, confusion, sweating, shivering, diarrhea (signs of serotonin syndrome)
- Severe headache
- Difficulty breathing or swallowing (signs of allergic reaction)
- Rash or hives
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, 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 prolonged QT interval visible on an electrocardiogram (ECG).
* If you are currently taking apomorphine.
This list is not exhaustive, and it is crucial to disclose all your medications, including prescription and over-the-counter (OTC) drugs, natural products, and vitamins, as well as any existing health problems, to your doctor and pharmacist. This will enable them to assess potential interactions and ensure safe use. Never start, stop, or adjust the dosage of any medication without first consulting your doctor to confirm it is safe to do so.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, 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 prolonged QT interval visible on an electrocardiogram (ECG).
* If you are currently taking apomorphine.
This list is not exhaustive, and it is crucial to disclose all your medications, including prescription and over-the-counter (OTC) drugs, natural products, and vitamins, as well as any existing health problems, to your doctor and pharmacist. This will enable them to assess potential interactions and ensure safe use. Never start, stop, or adjust the dosage of any medication without first consulting your doctor to confirm it is safe to do so.
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 (reported in one pediatric case)
- Serotonin syndrome (in cases of mixed overdose)
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 due to the risk of QT prolongation.
Drug Interactions
Contraindicated Interactions
- Apomorphine (concurrent use may cause profound hypotension and loss of consciousness)
Major Interactions
- Drugs that prolong QT interval (e.g., amiodarone, sotalol, quinidine, procainamide, disopyramide, dofetilide, dronedarone, chlorpromazine, thioridazine, mesoridazine, pimozide, ziprasidone, haloperidol, droperidol, methadone, moxifloxacin, erythromycin, pentamidine, cisapride, dolasetron, granisetron, palonosetron, tramadol)
- Phenytoin, Carbamazepine, Rifampin (potent CYP3A4 inducers, may decrease ondansetron levels)
- Tramadol (may reduce analgesic effect and increase risk of serotonin syndrome)
Moderate Interactions
- Serotonergic drugs (e.g., SSRIs, SNRIs, TCAs, MAOIs, mirtazapine, fentanyl, lithium, tramadol, triptans, St. John's Wort - increased risk of serotonin syndrome)
- Dexamethasone (may enhance antiemetic effect of ondansetron)
- CYP3A4 inhibitors (e.g., ketoconazole, erythromycin, cimetidine - may increase ondansetron levels, though not typically clinically significant)
Minor Interactions
- Alcohol (no significant interaction)
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: Prior to initiation, if risk factors for QT prolongation are present.
Serum Electrolytes (Potassium, Magnesium)
Rationale: Hypokalemia or hypomagnesemia can increase the risk of QT prolongation and Torsades de Pointes.
Timing: Prior to initiation, if risk factors for electrolyte imbalance are present.
Routine Monitoring
Nausea and Vomiting control
Frequency: Daily, as needed
Target: Absence or significant reduction of symptoms
Action Threshold: Persistent or worsening symptoms may require dose adjustment or alternative therapy.
Bowel movements
Frequency: Daily
Target: Regular bowel habits
Action Threshold: Constipation or diarrhea may require symptomatic treatment.
ECG (QTc interval)
Frequency: As clinically indicated, especially with high doses or concomitant QT-prolonging drugs
Target: <450 ms (men), <470 ms (women)
Action Threshold: QTc >500 ms or increase of >60 ms from baseline warrants discontinuation or dose reduction.
Symptom Monitoring
- Headache
- Constipation
- Diarrhea
- Fatigue
- Dizziness
- Dry mouth
- QT prolongation symptoms (e.g., palpitations, syncope, dizziness)
- Serotonin syndrome symptoms (e.g., agitation, hallucinations, rapid heart beat, fever, sweating, shivering, muscle stiffness, twitching, loss of coordination, nausea, vomiting, diarrhea)
Special Patient Groups
Pregnancy
Use during pregnancy should be considered only if clearly needed. While older classifications listed it as Category B, newer data suggest a low risk of major congenital malformations. However, some studies have suggested a small increased risk of oral clefts, though this remains controversial and not consistently replicated.
Trimester-Specific Risks:
First Trimester:
Potential, though controversial, small increased risk of oral clefts (e.g., cleft lip/palate).
Second Trimester:
Generally considered low risk.
Third Trimester:
Generally considered low risk.
Lactation
Ondansetron is excreted into human milk. The amount is small, and adverse effects in breastfed infants are not expected. However, monitor the infant for potential side effects like constipation or diarrhea. Use with caution.
Infant Risk:
Low risk (L3 - Moderately safe).
Pediatric Use
Safety and efficacy not established in pediatric patients younger than 6 months of age for CINV, and younger than 1 month of age for PONV. Dosing varies by age and weight. Pediatric patients may have a shorter half-life.
Geriatric Use
No dosage adjustment is generally required based on age alone. However, greater sensitivity of some older individuals cannot be ruled out. Elderly patients may be at increased risk for QT prolongation, especially if they have underlying cardiac conditions or are on other QT-prolonging medications. Monitor carefully.
Clinical Information
Clinical Pearls
- Ondansetron ODT should be placed on the tongue where it will disintegrate in seconds, then swallowed with saliva. No water is needed.
- It is crucial to check for concomitant medications that prolong the QT interval or increase the risk of serotonin syndrome.
- While generally well-tolerated, constipation is a common side effect, especially with prolonged use.
- For CINV, optimal efficacy is achieved when administered prior to chemotherapy, not after the onset of nausea.
- The 24 mg single dose for highly emetogenic chemotherapy is not recommended for patients with congenital long QT syndrome or those taking other QT-prolonging drugs.
Alternative Therapies
- Neurokinin-1 (NK1) receptor antagonists (e.g., aprepitant, fosaprepitant, 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/anxiety)
Cost & Coverage
Average Cost:
$10 - $50 per 30 tablets (4mg ODT)
Generic Available:
Yes
Insurance Coverage:
Tier 1 or Tier 2 (Generic)
General Drug Facts
If your symptoms or health issues persist or worsen, it is essential to contact your doctor for further guidance. To ensure safe and effective treatment, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so it's a good idea to check with your pharmacist for more information. If you have any questions or concerns about your 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.