Ondansetron 2mg/ml Inj, 2ml

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 vagal afferent nerves via 5-HT3 receptors, initiating the vomiting reflex. Ondansetron blocks this action, preventing nausea and vomiting.

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 prolonged QT interval, which may lead to a potentially life-threatening 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 mask the signs of a bowel block)

Other Possible Side Effects

Most people do not experience significant side effects, but some may occur. If you notice any of the following side effects or any other unusual symptoms, contact your doctor or seek medical attention if they bother you or do not go away:

Headache
Feeling tired or weak
Diarrhea or constipation
Feeling sleepy
Anxiety

This is not an exhaustive 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.

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 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 determine if it is safe to take this medication in conjunction with your other 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 all of your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. If you are pregnant, planning to become pregnant, or are breast-feeding, you must discuss this with your doctor. This conversation will help you understand the benefits and risks of taking this drug, both for you and your baby, allowing you to make an informed decision.

• Apomorphine (concurrent use may cause profound hypotension and loss of consciousness)
• QT-prolonging drugs (e.g., amiodarone, sotalol, quinidine, procainamide, disopyramide, dofetilide, dronedarone, chlorpromazine, thioridazine, pimozide, ziprasidone, haloperidol, methadone, citalopram, escitalopram, moxifloxacin, erythromycin, pentamidine, cisapride, dolasetron IV) - increased risk of Torsades de Pointes.

• Tramadol (reduced analgesic effect of tramadol due to inhibition of CYP2D6, which converts tramadol to its active metabolite)
• Phenytoin, Carbamazepine, Rifampin (CYP3A4 inducers - may decrease ondansetron plasma concentrations)
• Serotonergic drugs (e.g., SSRIs, SNRIs, TCAs, MAOIs, triptans, fentanyl, lithium, tramadol, St. John's Wort - increased risk of serotonin syndrome)
• Drugs that cause electrolyte abnormalities (e.g., diuretics - may increase risk of QT prolongation)

• Headache
• Constipation
• Diarrhea
• Fatigue
• Dizziness
• Lightheadedness
• Rash
• Signs of serotonin syndrome (agitation, hallucinations, rapid heart rate, fever, sweating, muscle rigidity, twitching, coordination problems, nausea, vomiting, diarrhea)
• Signs of allergic reaction (rash, itching, swelling, severe dizziness, trouble breathing)
• Signs of QT prolongation (palpitations, dizziness, fainting, seizures)

Ondansetron is generally considered low risk during pregnancy (Pregnancy Category B). While some studies have suggested a potential small increased risk of oral clefts or cardiac defects, overall data are conflicting and do not establish a clear causal link. Use only if clearly needed and potential benefits outweigh potential risks.

Ondansetron is excreted into human breast milk. Due to the potential for serious adverse reactions in breastfed infants (e.g., effects on serotonin receptors), a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother. The American Academy of Pediatrics considers it a drug for which the effect on nursing infants is unknown but may be of concern.

Safety and efficacy established for CINV in patients 6 months and older, and for PONV in patients 1 month and older. Dosing is weight-based or BSA-based. Younger children may have faster clearance, requiring more frequent dosing for CINV. Risk of QT prolongation should be considered, especially in neonates and infants.

No overall differences in safety or effectiveness have been observed between elderly and younger patients, but greater sensitivity of some older individuals cannot be ruled out. No dose adjustment is generally needed based solely on age, but consider reduced hepatic function and potential for polypharmacy (increased risk of QT-prolonging drug interactions).

• Administer IV ondansetron slowly (over 15 minutes) to reduce the risk of QT prolongation and other adverse effects.
• Be aware of the dose-dependent risk of QT prolongation; higher doses (e.g., 16 mg single IV dose) carry a greater risk.
• Correct electrolyte abnormalities (hypokalemia, hypomagnesemia) before administering ondansetron, especially in patients at risk for QT prolongation.
• Avoid concurrent use with apomorphine due to severe hypotensive risk.
• Monitor for signs of serotonin syndrome, especially if co-administered with other serotonergic agents.
• While generally well-tolerated, constipation is a common side effect; consider prophylactic laxatives in susceptible patients.

• Granisetron (another 5-HT3 antagonist)
• Palonosetron (another 5-HT3 antagonist, longer half-life)
• Dolasetron (another 5-HT3 antagonist)
• Dexamethasone (corticosteroid, often used in combination with 5-HT3 antagonists for CINV/PONV)
• NK1 receptor antagonists (e.g., aprepitant, fosaprepitant, rolapitant, netupitant/palonosetron combination - for CINV)
• Dopamine receptor antagonists (e.g., prochlorperazine, metoclopramide - for less severe nausea/vomiting)
• Antihistamines (e.g., promethazine, dimenhydrinate - for motion sickness or mild nausea)

If your symptoms or health problems persist or worsen, it is essential to contact your doctor for further guidance. To ensure safe use, never share your medication with others, and do not take medication prescribed for someone else. Store all medications in a secure location, out of reach of children and pets, to prevent accidental ingestion. Dispose of unused or expired medications properly. Unless instructed otherwise, do not flush medications down the toilet or pour them down the drain. If you are unsure about the proper disposal method, consult your pharmacist, who can also inform you about potential drug take-back programs in your area. Some medications may come with an additional patient information leaflet, which your pharmacist can provide. If you have any questions or concerns about your medication, discuss them with your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately contact your local poison control center or seek emergency medical attention. Be prepared to provide information about the medication taken, the amount, and the time of ingestion.