Onaseron 8mg/4ml Injection 1pc

✔️ Uses of Onaseron IM/IV Injection 8mg/4ml

Nausea, Vomiting

✔️ Side Effects of Onaseron IM/IV Injection 8mg/4ml

• Fast or slow or irregular heartbeat
• Chills
• Dry mouth
• Anxiety
• Excessive sweating
• Dizziness
• Skin rash and hives
• Injection site pain

✔️ Quick Suggestions:

• You have been prescribed Ondansetron for the prevention of nausea and vomiting caused after surgery or due to chemotherapy and radiotherapy.
• It is fast-acting and starts working within 30 minutes.
• If you vomit within one hour of taking a dose, take another dose.
• Avoid heavy meals and try eating small nourishing snacks throughout the day. Also, sip water regularly to help avoid dehydration.

✔️ Pharmacology

Ondansetron is a potent, highly selective 5HT3 receptor antagonist. Its exact mechanism in controlling nausea and vomiting is not fully understood. Chemotherapy and radiotherapy can trigger the release of 5HT in the small intestine, which initiates a vomiting reflex by activating vagal afferents through 5HT3 receptors. Ondansetron blocks this reflex. Additionally, activation of vagal afferents can release 5HT in the area postrema on the floor of the fourth ventricle, promoting emesis via a central mechanism. Therefore, ondansetron likely manages nausea and vomiting induced by chemotherapy and radiotherapy by antagonizing 5HT3 receptors in both the peripheral and central nervous systems. While the mechanisms for postoperative nausea and vomiting are not entirely known, they may share pathways with those of cytotoxic-induced nausea and vomiting.

✔️ Ondansetron Dosage and Administration

General Instructions

• May be taken with or without food.
• Reconstitution for IV infusion: Prior to IV infusion, dilute in 50 mL dextrose 5% injection or normal saline.

Adult Dosage

Oral Administration

Prevention of Nausea & Vomiting Associated with Chemotherapy:

• Highly emetogenic chemotherapy: 24 mg once, 30 minutes before the start of single-day chemotherapy.
• Moderately emetogenic chemotherapy:
  • 8 mg (one 8 mg tablet) administered 30 minutes before the start of chemotherapy.
  • A further 8 mg dose should be administered 8 hours after the first dose.
  • Then, 8 mg should be administered twice daily (every 12 hours) for 1-2 days after completion of chemotherapy.

Prevention of Nausea & Vomiting Associated with Radiotherapy:

• Total body irradiation: 8 mg 1-2 hours before each fraction of radiotherapy administered each day.
• Single high-dose fraction radiotherapy to abdomen:
  • 8 mg 1-2 hours before radiotherapy.
  • Then, 8 mg every 8 hours after the first dose for 1-2 days after radiation is completed.
• Daily fractionated radiotherapy to abdomen:
  • 8 mg 1-2 hours before radiotherapy.
  • Then, 8 mg every 8 hours after the first dose for each day of radiotherapy.

Prevention of Post-Operative Nausea & Vomiting:

• 16 mg 1 hour before the induction of anesthesia.

Nausea and Vomiting in Gastroenteritis:

• 8 mg three times daily.

Nausea and Vomiting in Pregnancy:

• 8 mg 2-3 times daily.

Parenteral Administration

Prevention of Nausea & Vomiting Associated with Chemotherapy:

• 0.15 mg/kg IV over 15 minutes, administered 30 minutes before chemotherapy.
• Then, repeated 4 and 8 hours after the first dose.
• Do not exceed 16 mg per dose.

Prevention of Post-Operative Nausea & Vomiting:

• 4 mg IV/IM immediately before anesthesia or after the procedure.
• The rate of administration should not be less than 30 seconds, preferably over 2 to 5 minutes.

Rectal Administration

• Nausea and Vomiting Associated with Cancer Chemotherapy:
  • 16 mg as a suppository, given 1-2 hours prior to treatment.

Elderly

• No dosage adjustment is needed.

Severe Hepatic Impairment (Child-Pugh Score ≥10)

• Do not exceed 8 mg/day.

Child Dosage

Oral Administration

Moderate Emetogenic Cancer Chemotherapy:

• Children (4-11 years):
  • 4 mg tablet taken 30 minutes before the start of chemotherapy.
  • Additional doses of 4 mg should be taken 4 and 8 hours after the first dose.
  • Then, 4 mg three times a day (every 8 hours) for 1-2 days after completion of chemotherapy.

Prevention of Nausea & Vomiting Associated with Radiotherapy:

• Children >12 years:
  • Total body irradiation: 8 mg 1-2 hours before each fraction of radiotherapy administered each day.
  • Single high-dose fraction radiotherapy to the abdomen:
    • 8 mg 1-2 hours before radiotherapy.
    • Then, 8 mg every 8 hours after the first dose for 1-2 days after radiation is completed.
  • Daily fractionated radiotherapy to the abdomen:
    • 8 mg 1-2 hours before radiotherapy.
    • Then, 8 mg every 8 hours after the first dose for each day of radiotherapy.

Nausea and Vomiting in Gastroenteritis:

• Children (>1 month): 0.15 mg/kg body weight three times daily.

Prevention of Post-Operative Nausea & Vomiting:

• Children >12 years: 16 mg 1 hour before the induction of anesthesia.

Parenteral Administration

Prevention of Nausea & Vomiting Associated with Chemotherapy:

• Children >6 months:
  • 0.15 mg/kg IV over 15 minutes, administered 30 minutes before chemotherapy.
  • Then, repeated 4 and 8 hours after the first dose.
  • Do not exceed 16 mg per dose.

Prevention of Post-Operative Nausea & Vomiting:

• Children 1 month-12 years:
  • <40 kg: 0.1 mg/kg.
  • ≥40 kg: 4 mg.
• Administer IV as a single dose immediately before induction of anesthesia or shortly post-operatively if nausea or vomiting occurs.
• The rate of administration should not be less than 30 seconds, preferably over 2 to 5 minutes.

Renal Dose

• Renal impairment: Dose adjustment is not necessary.

✔️ Interaction

✔️ Contraindications

Contraindicated in patients known to have hypersensitivity to the drug or any of its components. 

✔️ Drug Interactions

• Tramadol: Ondansetron may reduce the analgesic effect.
• CYP3A4 Inducers (e.g., rifampicin): May reduce ondansetron levels/effects.
• QT-Prolonging Agents (e.g., antiarrhythmics): Concomitant use may cause additive QT interval prolongation.
• Cardiotoxic Drugs (e.g., anthracyclines): May increase the risk of arrhythmias.
• Apomorphine: This may increase the hypotensive effect, potentially fatal.

✔️ Precautions

• Gastrointestinal: May mask progressive ileus and/or gastric distension.
• Hepatic Impairment: Use with caution in severe cases.
• Pregnancy and Lactation: Use under medical supervision.
• Monitoring: ECG monitoring is recommended for patients with electrolyte abnormalities (e.g., hypomagnesemia, hypokalaemia), congestive heart failure (CHF), bradyarrhythmias, or those on medications that can prolong the QT interval.

✔️ Storage Conditions:

Protect from light and moisture.