Ge Ou Shu

Uses

Ge Ou Shu Tablet is used for: Nausea and vomiting associated with initial and repeat course of emetogenic cancer therapy, including high dose of cisplatin. Nausea and vomiting associated with radiation, including total body irradiation and fractionated abdominal radiation.

Ge Ou Shu Injection is used for: The prevention of nausea and vomitng associated with initial and repeat courses of emetogenic cancer chemotherapy, therapy including high dose cisplatin. The prevention and treatment of post operative nausea and vomiting.

Ge Ou Shu is also used to associated treatment for these conditions: Nausea and vomiting

How Ge Ou Shu works

Ge Ou Shu is a potent, selective antagonist of 5-HT₃ receptors. The antiemetic activity of the drug is brought about through the inhibition of 5-HT3 receptors present both centrally (medullary chemoreceptor zone) and peripherally (GI tract). This inhibition of 5-HT3 receptors in turn inhibits the visceral afferent stimulation of the vomiting center, likely indirectly at the level of the area postrema, as well as through direct inhibition of serotonin activity within the area postrema and the chemoreceptor trigger zone.

Dosage

Ge Ou Shu dosage

Tablet-

Emetogenic Chemotherapy: The recommended adult dosage of oral Ge Ou Shuis 2 mg once daily or 1 mg twice daily. In the 2 mg once-daily regimen, two 1 mg tablets is given up to 1 hour before chemotherapy. In the 1 mg twice-daily regimen, the first 1 mg tablet is given up to 1 hour before chemotherapy, and the second tabletis given 12 hours after the first. Either regimen is administered only on the day(s) chemotherapy is given. Continued treatment, while not on chemotherapy, has not been found to be useful.

Injection-

Chemotherapy Induced Nausea and Vomiting:

• Adults: The recommended dosage for Ge Ou Shu Injection is 10 mcg/kg administered intravenously within 30 minutes before initiation of chemotherapy, and only on the day(s) chemotherapy is given. Ge Ou Shu Injection may be administered intravenously either undiluted over 30 seconds, or diluted with 0.9% Sodium Chloride or 5% Dextrose and infused over 5 minutes. As a general precaution, Ge Ou Shu Injection should not be mixed in solution with other drugs.
• Paediatric Patients: The recommended dose in paediatric patients 2 to 16 years o f age is 10 mcg/kg. Paediatric patients under 2 years o f age have not beenstudied.
• Geriatric Patients, Renal Failure Patients or Hepatically Impaired Patients: No dosage adjustment is required.

Treatment of Postoperative Nausea and Vomiting:

• Adults: The recommended dosage for prevention of postoperative nausea and vomiting is, a single dose of 1 mg of Ge Ou Shu should be diluted to 5 ml andadministered as a slow intravenous injection (over 30 seconds). Administration should be completed prior toinduction of anesthesia. The recommended dosage for the treatment of nausea and vomiting after surgery is 1 mg of Ge Ou Shu undiluted, administered intravenously over 30 seconds.
• Paediatric Patients: Safety and effectiveness of Ge Ou Shu Injection have not been established in paediatric patients for the prevention or treatment of post operative nausea or vomiting.
• Geriatricpatients, Renal Failure Patients or Hepatically Impaired Patients: No dosage adjustment is required.

Side Effects

Headache, insomnia, constipation, diarrhoea, elevated hepatic transaminases; QT prolongation; bradycardia, palpitations, sick sinus syndrome, chest pain. Application site reactions (transdermal): Rash, pain, erythema, pruritus, irritation, burn, vesicles, urticaria, discolouration; patch non-adhesion.

Toxicity

LD₅₀>2000 mg/kg (rat, oral)

Precaution

Patient with cardiac co-morbidities, on cardiotoxic chemotherapy and/or woth concomitant electrolyte abnormalities. May mask progressive ileus and/or gastric distention. Childn. Pregnancy and lactation.

Interaction

Induced metabolism with phenobarbital. Risk of serotonin syndrome with other serotonergic agents e.g. SSRIs, and serotonin and norepinephrine reuptake inhibitors (SNRIs). Altered clearance with CYP enzyme inducers or inhibitors. Concomitant use with drugs known to prolong QT interval may result in clinical consequences.

Food Interaction

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

Ge Ou Shu Drug Interaction

Major: fentanyl, fentanylMinor: sulfamethoxazole / trimethoprim, sulfamethoxazole / trimethoprimUnknown: diphenhydramine, diphenhydramine, pregabalin, pregabalin, acetaminophen, acetaminophen, acetaminophen, acetaminophen, cyanocobalamin, cyanocobalamin, ascorbic acid, ascorbic acid, cholecalciferol, cholecalciferol, ondansetron, ondansetron

Elimination Route

Absorption of is rapid and complete, though oral bioavailability is reduced to about 60% as a result of first pass metabolism.

Half Life

4-6 hours in healthy patients, 9-12 hours in cancer patients

Clearance

• 0.52 L/h/kg [Cancer Patients with 1 mg bid for 7 days]
• 0.41 L/h/kg [Healthy subject with a single 1 mg dose]

Elimination Route

The remainder of the dose is excreted as metabolites, 48% in the urine and 38% in the feces.

Pregnancy & Breastfeeding use

Pregnancy: Category B. No evidence of impaired fertility or harm to the animal fetus have been found. However, this drug may be used in pregnancy only if clearly needed.

Lactation: It is not known whether granisetron is excreted in human milk. So cautions hould be exercised when granisetron is administered to a nursing mother.

Contraindication

Ge Ou Shu is contraindicated in patients with known hypersensitivity to granisetron.

Special Warning

Pediatric Uses: Safety and effectiveness of granisetron in paediatric patients under 2 years have not been established.

Geriatric use: Efficacy and safety were maintained with increasing age

Acute Overdose

Symptoms: Mild headache.

Management: Symptomatic treatment.

Storage Condition

Store between 15-30°C. Protect from light.

Innovators Monograph

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