Ondansetron - Labesfal

Uses

Ondansetron - Labesfal is used for:

• Prevention of nausea and vomiting associated with highly emetogenic cancer chemotherapy
• Prevention of nausea and vomiting associated with radiotherapy
• Prevention of post operative nausea and vomiting

Ondansetron - Labesfal is also used to associated treatment for these conditions: Chemotherapy-Induced Nausea and Vomiting (CINV), Cholestatic pruritus, Post Operative Nausea and Vomiting (PONV), Uremic Pruritus, Radiation therapy induced nausea and vomiting, Severe Hyperemesis gravidarum

How Ondansetron - Labesfal works

Ondansetron - Labesfal is a selective antagonist of the serotonin receptor subtype, 5-HT3 .

Cytotoxic chemotherapy and radiotherapy are associated with the release of serotonin (5-HT) from enterochromaffin cells of the small intestine, presumably initiating a vomiting reflex through stimulation of 5-HT3 receptors located on vagal afferents . Ondansetron - Labesfal may block the initiation of this reflex. Activation of vagal afferents may also cause a central release of serotonin from the chemoreceptor trigger zone of the area postrema, located on the floor of the fourth ventricle . Thus, the antiemetic effect of ondansetron is probably due to the selective antagonism of 5-HT3 receptors on neurons located in either the peripheral or central nervous systems, or both .

Although the mechanisms of action of ondansetron in treating postoperative nausea and vomiting and cytotoxic induced nausea and vomiting may share similar pathways, the role of ondansetron in opiate-induced emesis has not yet been formally established .

Dosage

Ondansetron - Labesfal dosage

Prevention of chemotherapy induced nausea & vomiting (CINV):

Adult-

• Tablet and oral solution: The recommended adult oral dosage of Ondansetron - Labesfal is 24 mg given as three 8 mg tablets in highly emetogenic chemotherapy. In case of moderately emetogenic chemotherapy the oral dose is one 8 mg Ondansetron - Labesfal tablet or 10 ml of Ondansetron - Labesfal oral solution given twice daily.
• Injection: The recommended i.v. dose of Ondansetron - Labesfal is a single 32 mg dose or three 0.15 mg/kg doses. A single 32 mg dose is infused over 15 minutes beginning 30 minutes before the start of emetogenic chemotherapy. Subsequent doses (0.15 mg/kg) are administered 4 and 8 hours after the first dose of Ondansetron - Labesfal.
• Suppository: The recommended adult dose is one 16 mg suppository 1-2 hours before treatment. Ondansetron - Labesfal should be continued for upto 5 days after a course of treatment.The recommended dose is one suppository daily.

Pediatric patients-

• Tablet and oral solution:for pediatric patients 4 through 11 years of age the dosage is one 4 mg Ondansetron - Labesfal tablet or 5ml of Ondansetron - Labesfal solution should be administered 3 times a day for 1 to 2 days after completion of chemotherapy.
• Injection: the dosage in pediatric patients 4 to 18 years of age should three 0.15-mg/kg doses.
• Suppository:Not recommended.

Radiotherapy induced nausea and vomiting:

Adult-

• Tablet and oral solution: the recommended oral dosage is one 8mg Ondansetron - Labesfal tablet or 10ml of Ondansetron - Labesfal oral solution given 3 times daily.

Post operative nausea & vomiting (PONV):

Adult-

• Tablet and oral solution: The recommended dosage is 16 mg given as two 8 mg Ondansetron - Labesfal tablets or 20 ml of Ondansetron - Labesfal oral solution 1hour before induction of anesthesia.
• Injection: The recommended I.V. dosage of Ondansetron - Labesfal for adults is 4 mg undiluted administered intravenously in not less than 30 seconds, preferably over 2 to 5 minutes, immediately before induction of anesthesia, or postoperatively if the patient experiences nausea and/or vomiting occurring shortly after surgery. Alternatively, 4 mg undiluted may be administered intramuscularly as a single injection for adults. In patients who do not achieve adequate control of postoperative nausea and vomiting following a single, prophylactic, preinduction, I.V. dose of Ondansetron - Labesfal 4 mg, administration of a second I.V. dose of 4 mg Ondansetron - Labesfal postoperatively does not provide additional control of nausea and vomiting.
• Suppository: The recommended adult dose is one 16 mg suppository 1-2 hours before treatment. Ondansetron - Labesfal should be continued for upto 5 days after a course of treatment.The recommended dose is one suppository daily.

Pediatric patients-

• Injection: The recommended I.V. dosage of Ondansetron - Labesfal for pediatric patients (2 to 12 years of age) isa single 0.1-mg/kg dose for pediatric patients weighing 40 kg or less, or a single 4 mg dose for pediatric patients weighing more than 40 kg. The rate of administration should not be less than 30 seconds, preferably over 2 to 5 minutes. Little information is available about dosage in pediatric patients younger than 2 years of age.
• Suppository: Not recommended.

Prior to IV infusion, dilute in 50 ml dextrose 5% inj or normal saline.

Side Effects

The most common adverse effects include headache, constipation, diarrhea. In chemotherapy induced nausea and vomiting rash has occurred in approximately 1% of patients receiving Ondansetron - Labesfal. Blurred vision, chest pain with or without ST segment depression, cardiac arrhythmias, hypotension and bradycardia have been rarely reported.

Toxicity

At present, there is little information concerning overdosage with ondansetron . Nevertheless, there have been certain cases of somewhat idiosyncratic adverse effects associated with particular dosages of ondansetron used .

“Sudden blindness” (amaurosis) of 2 to 3 minutes duration plus severe constipation occurred in one patient that was administered 72 mg of ondansetron intravenously as a single dose . Hypotension (and faintness) occurred in another patient that took 48 mg of oral ondansetron . Following infusion of 32 mg over only a 4-minute period, a vasovagal episode with transient second-degree heart block was observed . Neuromuscular abnormalities, autonomic instability, somnolence, and a brief generalized tonic-clonic seizure (which resolved after a dose of benzodiazepine) were observed in a 12-month-old infant who ingested seven or eight 8-mg ondansetron tablets (approximately forty times the recommended 0.1-0.15 mg/kg dose for a pediatric patient) . In all instances, however, the events resolved completely .

The safety of ondansetron for use in human pregnancy has not been established . Ondansetron - Labesfal is not teratogenic in animals . However, as animal studies are not always predictive of human response, the use of ondansetron in pregnancy is not recommended .

Ondansetron - Labesfal is excreted in the milk of lactating rats . It is not known if it is excreted in human milk, however, nursing is not recommended during treatment with ondansetron .

Insufficient information is available to provide dosage recommendations for children 3 years of age or younger .

Precaution

Hypersensitivity reactions have been reported in patients who have exhibited hypersensitivity to other 5-HT3 receptor antagonists. Ondansetron - Labesfal is not a drug that stimulates gastric or intestinal peristalsis. It should not be used instead of nasogastric suction. The use of Ondansetron - Labesfal in patients following abdominal surgery or in patients with chemotherapy-induced nausea and vomiting may mask a progressive ileus and/or gastric distension.

Interaction

In patients treated with potent inducers of CYP3A4 (i.e Phenytoin, Carbamazepine or Rifampicin), the oral clearance of Ondansetron - Labesfal was increased and Ondansetron - Labesfal blood concentrations were decreased. Data from small studies indicate that Ondansetron - Labesfal may reduce the analgesic effect of tramadol.

Food Interaction

• Take with or without food. The absorption is unaffected by food.

Ondansetron - Labesfal Drug Interaction

Major: duloxetineModerate: polyethylene glycol 3350, acetaminophen / hydrocodone, albuterolUnknown: amphetamine / dextroamphetamine, diphenhydramine, omega-3 polyunsaturated fatty acids, fluticasone nasal, pregabalin, metoprolol, metoprolol, acetaminophen, levothyroxine, acetaminophen, cyanocobalamin, ascorbic acid, ergocalciferol, cholecalciferol, alprazolam, cetirizine

Ondansetron - Labesfal Disease Interaction

Major: QT interval prolongationModerate: liver disease

Volume of Distribution

The volume of distribution of ondansetron has been recorded as being approximately 160L .

Elimination Route

Ondansetron - Labesfal is absorbed from the gastrointestinal tract and undergoes some limited first-pass metabolism . Mean bioavailability in healthy subjects, following administration of a single 8-mg tablet, was recorded as being approximately 56% to 60% . Bioavailability is also slightly enhanced by the presence of food .

Ondansetron - Labesfal systemic exposure does not increase proportionately to dose . The AUC from a 16-mg tablet was 24% greater than predicted from an 8-mg tablet dose . This may reflect some reduction of first-pass metabolism at higher oral doses .

Half Life

The half-life of ondansetron after either an 8 mg oral dose or intravenous dose was approximately 3-4 hours and could be extended to 6-8 hours in the elderly .

Clearance

The clearance values determined for ondansetron in various patient age groups were recorded as approximately 0.38 L/h/kg in normal adult volunteers aged 19-40 yrs, 0.32 L/h/kg in normal adult volunteers aged 61-74 yrs, 0.26 L/h/kg in normal adult volunteers aged >=75 yrs .

Elimination Route

Following oral or IV administration, ondansetron is extensively metabolised and excreted in the urine and faeces .

Pregnancy & Breastfeeding use

In pregnancy: Pregnancy category B. Reproduction studies at daily oral dose up to 10 and 30 mg/kg/day have been performed in animals and have revealed no evidence of impaired fertility harm to the fetus due to Ondansetron - Labesfal. There are, however, no adequate and well-controlled studies in pregnant women. So the drug should be used in pregnancy only if clearly needed.

In lactation: Ondansetron - Labesfal excretes in milk of lactating animals. Caution should be exercised when Ondansetron - Labesfal is administered to nursing mother.

Contraindication

Ondansetron - Labesfal is contraindicated in patients with known hypersensitivity to the drug.

Special Warning

Pediatric use: Can be given in children 1 month of age and above.

Geriatric use: No dosage adjustment is necessary in the elderly.Dosage adjustment for patients with impaired hepatic function:

• Tablet and Oral Solution: The total daily dose of 8 mg should not be exceeded.
• Injection: A single maximal dose of 8 mg to be infused over 15 minutes beginning 30 minutes before the start of the emetogenic chemotherapy is recommended.
• Suppository: Not recommended

Acute Overdose

There is no specific antidote for Ondansetron - Labesfal overdose. In addition to the adverse events, hypotension (and faintness) occurred in a patient that took 48 mg of AVONA tablets. In all instances, the events resolved completely.

Storage Condition

Store in a cool and dry place, protected from light and moisture. For suppository- Store below 25º c.

Innovators Monograph

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