GRANITRYL 1MG/1ML

Indications

• Nausea and vomiting induced by cytotoxic chemotherapy
• Prevention of postoperative nausea and vomiting

Dosage

Children: For children aged 6 months to 17 years, refer to the BNF for Children for appropriate dosing guidelines, as individual dosage may vary based on age, weight, and specific treatment protocols.

Adults: For intravenous administration, the typical adult dose is 1 mg, given before the induction of anesthesia, diluted in 5 mL and administered over 30 seconds. For prevention of nausea and vomiting related to chemotherapy, it can be given for 3-5 days as needed.

Mechanism of action

Granisetron works by selectively blocking the 5-HT3 receptors, which are involved in the vomiting reflex. By antagonizing these receptors in both the central nervous system and the gastrointestinal tract, granisetron reduces the stimulation of the vomiting center, thus preventing nausea and vomiting.

Pharmacodynamics

Granisetron's pharmacodynamic effects are primarily based on its ability to inhibit the action of serotonin at the 5-HT3 receptor sites. This action reduces the incidence of nausea and vomiting, especially in patients undergoing chemotherapy or surgery. The onset of action is typically rapid, with significant effects observed within 30 minutes to 2 hours after administration.

Pharmacokinetics

Granisetron is well-absorbed when administered intravenously or orally. It exhibits a volume of distribution of approximately 4-5 L/kg and is primarily metabolized in the liver via cytochrome P450 enzymes. The elimination half-life ranges from 9 to 13 hours, allowing for once-daily dosing in many cases. Granisetron is primarily excreted in urine, with a small percentage excreted unchanged.

Adverse effects

• Extrapyramidal symptoms
• QT interval prolongation
• Serotonin syndrome
• Decreased appetite
• Dry mouth
• Flushing
• Generalized edema
• Vertigo
• Dystonia

Precautions

• Caution is advised in hepatic impairment
• Patients should avoid sun exposure to the patch site during use and for 10 days after removal

Pregnancy

Manufacturer advises to avoid use during pregnancy.

Breast-feeding

Avoid; no information available regarding safety during breastfeeding.

Storage

Store in a dry place, protected from light. Keep out of reach of children.

Formulations

• {'formulation': 'Powder for solution for infusion', 'strength': '1 mg per 1 ml', 'pack_size': '10 ampoules'}
• {'formulation': 'Granisetron 3 mg/3 ml concentrate for solution for injection', 'pack_size': '10 ampoules'}
• {'formulation': 'Granisetron 1 mg tablets', 'pack_size': '10 tablets'}
• {'formulation': 'Granisetron 2 mg tablets', 'pack_size': '10 tablets'}
• {'formulation': 'Transdermal patch', 'strength': '3.1 mg per 24 hours', 'pack_size': '1 patch'}

Dosage

Children: Refer to the specific drug's prescribing information for detailed dosage.

Adults: Refer to the specific drug's prescribing information for detailed dosage.

Mechanism of action

The mechanism of action varies depending on the specific drug that is in hydrochloride form. Generally, hydrochloride salts dissociate in solution to release the active drug, which then interacts with specific receptors or enzymes in the body to exert its pharmacological effects.

Pharmacodynamics

Pharmacodynamics will depend on the specific active ingredient in the hydrochloride formulation. Typically, the pharmacodynamics involve the interaction of the drug with its target receptors, leading to a physiological response. This can include altering neurotransmitter levels, inhibiting enzymes, or blocking receptors, among other actions.

Pharmacokinetics

Pharmacokinetics will also vary based on the specific drug. Generally, hydrochloride salts are well absorbed after oral administration, with peak plasma concentrations occurring within a few hours. They may undergo first-pass metabolism in the liver, and their elimination half-life can vary widely depending on the drug's characteristics.

Pregnancy

Consult with healthcare provider before use; risk versus benefit should be evaluated.

Breast-feeding

Use with caution; monitor for potential adverse effects in the infant.

Storage

Store in a cool, dry place away from light; keep out of reach of children.