Ondamax 4 tablet: Each film coated tablet contains Ondansetron Hydrochloride USP equivalent to Ondansetron 4 mg.
Ondamax 8 tablet: Each film coated tablet contains Ondansetron Hydrochloride USP equivalent to Ondansetron 8 mg.
Ondamax Oral Solution: Each 5 ml contains Ondansetron Hydrochloride USP equivalent to Ondansetron 4 mg.
Ondansetron is a highly selective 5-hydroxytryptamine-3 (5-HT3) receptor antagonist. The mechanism of action of Ondansetron in the management of the nausea and vomiting induced by cytotoxic chemotherapy and radiotherapy is probably due to antagonism of 5-HT3 receptors on neurons located both in the peripheral and central nervous system. The mechanism of action in postoperative nausea and vomiting are not known but there may be common pathways with cytotoxic induced nausea and vomiting.
Absorption: Ondansetron is completely absorbed from the gastrointestinal tract and undergoes some first-pass metabolism.
Distribution: Ondansetron is distributed with volume of distribution (1.9 - 2.6 L/kg). Plasma protein binding is 70% and crosses membranes readily.
Metabolism: Biotransformation pathway involves the primary metabolic pathway that is hydroxylation followed by subsequent glucuronide or sulfate conjugation.
Elimination: Ondansetron is excreted in the urine (approx. 65%) and feces (35%) after extensive hepatic metabolism. The plasma half life of Ondansetron is 3.5 hours.
Ondansetron is indicated for the management of nausea and vomiting induced by cytotoxic chemotherapy and radiotherapy. It is also indicated for the prevention of post operative nausea and vomiting.
DOSAGE AND ADMINISTRATION:
Postoperative nausea and vomiting:
The recommended dose is 16 mg 1 hour before induction of anesthesia. Chemotherapy induced nausea and vomiting:
a) For highly emetogenic cancer chemotherapy : The recommended adult oral dose is 24 mg administered 30 minutes before the start of single day highly emetogenic chemotherapy.
Geriatric use: same as the general population.
b) For moderately emetogenic cancer chemotherapy: The recommended adult oral dose is 8 mg twice daily. The first dose should be administered 30 minutes before the start of emetogenic chemotherapy and with a subsequent dose 8 hours after the first dose. Ondansetron should be administered twice a day (every 12 hours) for 1 to 2 days after completion of chemotherapy.
Radiotherapy induced nausea and vomiting:
The recommended oral dose is 8 mg three times daily. For total body irradiation: 8 mg should be administered 1 to 2 hours before each fraction of radiotherapy administered each day. For single high dose fraction radiotherapy to the abdomen, 8 mg should be administered 1 to 2 hours before radiotherapy, with subsequent doses every 8 hours after the first dose for 1 to 2 days after completion of radiotherapy.
For daily fractionated radiotherapy to the abdomen, 8 mg should be administered 1 to 2 hours before radiotherapy, with subsequent doses every 8 hours after the first dose for each day radiotherapy is given.
Ondansetron is contraindicated in patients with known hypersensitivity to the drug.
Generally Ondansetron is well tolerated. However few side effects including headache, diarrhea, fatigue, dizziness and constipation may be seen after Ondansetron is administered.
USE IN PREGNANCY & LACTATION:
Pregnancy: There are however, no adequate and well-controlled studies in pregnant women.
Nursing mother: It is not known whether Ondansetron is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when Ondansetron is administered to nursing women.
Ondansetron is not a drug that stimulates gastric or intestinal peristalsis. It should not be used instead of nasogastric suction. The use of Ondansetron in patients following abdominal surgery or in patients with chemotherapy induced nausea and vomiting may mask a progressive ileus and/or gastric distension.
In patients treated with potent inducers of CYP3A4 (i.e. Phenytoin, Carbamazepine or Rifampicin), the oral clearance of Ondansetron was increased and Ondansetron blood concentrations were decreased. Data from small studies indicates that Ondansetron may reduce the analgesic effect of Tramadol.
Store in a cool and dry place, protected from light & moisture.
Keep out of the reach of the children.
Ondamax 4 tablet: Each box contains 3x10 tablets in blister pack.
Ondamax 8 tablet: Each box contains 3x10 tablets in blister pack.
Ondamax Oral Solution: Each bottle contains 50 ml oral solution.