Ondansetron 4mg/2ml Pf Syr Inj, 2ml

Ondansetron is a selective serotonin 5-HT3 receptor antagonist. Chemotherapeutic agents and radiation therapy cause release of serotonin (5-HT) from enterochromaffin cells of the small intestine, which then activate 5-HT3 receptors located on vagal afferents, initiating the vomiting reflex. Ondansetron blocks the initiation of this reflex both peripherally on vagal nerve terminals and centrally in the chemoreceptor trigger zone (CTZ) in the area postrema.

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 (fast or irregular) or fainting, as this medication can cause a type of abnormal heartbeat (prolonged QT interval), which may lead to another type of unsafe abnormal heartbeat (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
+ Excessive sweating
+ Severe diarrhea
+ Upset stomach or vomiting
+ Severe 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, as this medication may mask the signs of a bowel block

Other Possible Side Effects

Most people do not experience severe side effects, and many have no side effects or only minor ones. However, if you notice any of the following side effects or any other unusual symptoms, contact your doctor or seek medical attention:

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, consult 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 and its symptoms.
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 discuss all your medications, including prescription and over-the-counter drugs, natural products, and vitamins, with your doctor and pharmacist. They will help determine if it is safe to take this medication alongside your other treatments and health conditions.

Remember, do not start, stop, or adjust 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 currently breast-feeding, be sure to discuss this with your doctor. You and your doctor will need to carefully weigh the benefits and risks of using this medication to ensure the best possible outcome for both you and your baby.

• Apomorphine (concurrent use with ondansetron is contraindicated due to risk of profound hypotension and loss of consciousness)

• Drugs that prolong the QT interval (e.g., amiodarone, sotalol, quinidine, procainamide, disopyramide, dofetilide, dronedarone, chlorpromazine, haloperidol, thioridazine, ziprasidone, moxifloxacin, erythromycin, pentamidine, methadone, citalopram, escitalopram, fluoxetine, sertraline, tricyclic antidepressants)
• Serotonergic drugs (e.g., SSRIs, SNRIs, MAOIs, tricyclic antidepressants, lithium, tramadol, fentanyl, triptans, St. John's Wort) - increased risk of serotonin syndrome

• Phenytoin, Carbamazepine, Rifampin (strong CYP3A4 inducers may decrease ondansetron plasma concentrations)
• Tramadol (ondansetron may reduce the analgesic effect of tramadol)

• Not available

• Headache
• Constipation
• Diarrhea
• Fatigue
• Dizziness
• Lightheadedness
• Rash
• Signs of serotonin syndrome (agitation, hallucinations, rapid heart rate, fever, sweating, shivering, muscle stiffness or twitching, loss of coordination, nausea, vomiting, diarrhea)
• Signs of QT prolongation (palpitations, dizziness, syncope, seizures)

Ondansetron was previously classified as Pregnancy Category B. While generally considered low risk for short-term use, some conflicting data suggest a possible, small increased risk of oral clefts (e.g., cleft lip/palate) when used during the first trimester. Use during pregnancy should be considered only if clearly needed and the potential benefits outweigh the potential risks. Discuss risks and benefits with a healthcare provider.

Ondansetron is excreted into breast milk. The amount is small, and adverse effects in breastfed infants are not commonly reported. However, due to the potential for serious adverse reactions in the breastfed infant, 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. L3 (Moderately Safe).

Dosing is established for children ≥1 month for PONV and ≥6 months for CINV. Generally well-tolerated, but children have a shorter half-life. Monitor for QT prolongation, especially in those with underlying cardiac conditions or electrolyte imbalances.

No dosage adjustment is generally required based on age alone. However, elderly patients may be more susceptible to QT prolongation and should be monitored, especially if they have underlying cardiac conditions, electrolyte imbalances, or are on concomitant QT-prolonging medications. Hepatic function may be reduced in the elderly, and severe hepatic impairment requires dose adjustment.

• Administer IV ondansetron slowly, preferably over 2-5 minutes (or 15 minutes for higher CINV doses), to minimize the risk of transient vision changes, dizziness, or syncope.
• Correct hypokalemia and hypomagnesemia prior to ondansetron administration to reduce the risk of QT prolongation.
• Be aware of the potential for serotonin syndrome when co-administered with other serotonergic agents.
• Ondansetron can cause constipation; consider prophylactic laxatives in patients prone to constipation, especially with prolonged use.
• While effective for nausea and vomiting, ondansetron is not effective for motion sickness.

• Other 5-HT3 receptor antagonists (e.g., granisetron, palonosetron, dolasetron)
• Neurokinin-1 (NK1) receptor antagonists (e.g., aprepitant, fosaprepitant, netupitant/palonosetron)
• Corticosteroids (e.g., dexamethasone)
• Dopamine receptor antagonists (e.g., prochlorperazine, metoclopramide, droperidol)
• Antihistamines (e.g., promethazine, dimenhydrinate)
• Cannabinoids (e.g., dronabinol, nabilone)

If your symptoms or health problems do not improve or worsen over time, it is essential to contact your doctor for further evaluation and 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.

Proper disposal of unused or expired medications is crucial. Do not dispose of them by flushing down the toilet or pouring down the drain unless specifically instructed to do so by a healthcare professional or pharmacist. If you are unsure about the correct disposal method, consult with your pharmacist, who can provide guidance on safe disposal practices. Many communities offer drug take-back programs, which can be an alternative disposal option.

Some medications may come with an additional patient information leaflet. If you have questions or concerns about your medication, it is best to consult with your pharmacist, who can provide more detailed information.

If you suspect an overdose has occurred, immediately contact your local poison control center or seek emergency medical attention. Be prepared to provide critical information, including the name of the medication taken, the amount, and the time it was taken, to ensure prompt and effective treatment.