Granisetron

Introduction: Granisetron is an antiemetic medicine used to prevent and control nausea and vomiting caused by chemotherapy, radiation therapy and surgery.

How it works: Granisetron is a selective 5-HT3 receptor antagonist. It blocks serotonin in the chemoreceptor trigger zone to prevent the vomiting reflex.

Important Information: Take 2 mg orally 1 hour before chemotherapy or 0.01 mg/kg IV 30 minutes before chemotherapy. For postoperative nausea prevention, give 1 mg IV before anesthesia induction.

• Chemotherapy-induced nausea and vomiting - initial and repeat courses
• Radiation-induced nausea and vomiting - total body irradiation and fractionated abdominal radiation
• Postoperative nausea and vomiting - prevention and treatment

Anti-emetic drugs, Supportive Care Therapy

5-HT3 Receptor Antagonist

Granisetron 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 and through direct inhibition of serotonin activity within the area postrema and the chemoreceptor trigger zone.

Granisetron blocks 5-HT3 receptors to prevent serotonin action in the brain, thereby suppressing the vomiting reflex.

Injection (Chemotherapy):

• Adults: 10 mcg/kg IV (30 minutes before chemotherapy)
• Children (2-16 years): 10 mcg/kg IV

Injection (Postoperative):

• Prevention: 1 mg IV (before anesthesia induction)
• Treatment: 1 mg IV (over 30 seconds)

Tablet (Chemotherapy):

• 2 mg once daily or 1 mg twice daily

Tablet (Radiation):

• 2 mg once daily (1 hour before radiation)

Elderly, Renal/Hepatic: No dosage adjustment required

* Use as directed by the registered physician

Oral tablet or intravenous (IV) injection. Can be taken with or without food. Swallow whole tablets. IV injection can be given over 30 seconds or as 5-minute infusion.

If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and follow your regular schedule. Do not double the dose.

Common Side Effects:

• Headache
• Constipation
• Diarrhea
• Weakness
• Sleepiness
• Dizziness
• Abdominal pain
• Dyspepsia
• Anxiety
• Insomnia

Precautions:

• Caution in patients with cardiac comorbidities, cardiotoxic chemotherapy and electrolyte abnormalities
• May mask progressive ileus and gastric distention
• Caution in pregnancy and lactation
• Be cautious while driving (may cause drowsiness)

Contraindications:

• Hypersensitivity to Granisetron or any of its components

Drug Interactions:

• Phenobarbital may induce metabolism of granisetron

Food Interactions:

• It is not known whether it is safe to consume alcohol. Please consult your doctor.

Use in Pregnancy: Generally considered safe during pregnancy. Animal studies have shown low or no adverse effects.

Use in Lactation: Probably safe during breastfeeding. Limited data suggests the drug does not represent significant risk to the baby.

Pediatric Use: IV dose established for children 2-16 years. Safety and efficacy in children under 2 years not established.

Geriatric Use: Efficacy and safety maintained with increasing age. No dosage adjustment required.

Renal Impairment: Safe in kidney disease. No dosage adjustment required (total clearance not affected even with CrCl <30).

Hepatic Impairment: Safe in liver disease. No dosage adjustment required.

Overdose: Overdose may cause headache, nausea, diarrhea. Symptomatic and supportive treatment should be given.

Storage: Injection: Store below 25°C. Protect from light. Tablet: Protect from light.

Granisetron