Granisetron hydrochloride
Granisetron hydrochloride (Kytril)
Granisetron hydrochloride
(gran- ISS-eh-tron)
Pregnancy Category: B Kytril (Rx)

Classification: Antinauseant and antiemetic

Action/Kinetics: Selective 5-HT ₃ (serotonin) receptor antagonist with little or no affinity for other 5-HT, beta-adrenergic, dopamine, or histamine receptors. During chemotherapy-induced vomiting, mucosal enterochromaffin cells release serotonin, which stimulates 5-HT ₃ receptors. The stimulation of 5-HT ₃ receptors by serotonin causes vagal discharge resulting in vomiting. Granisetron blocks serotonin stimulation and subsequent vomiting. In adult cancer clients undergoing chemotherapy, infusion of a single 40-mcg/kg dose over 5 min produced the following data. Peak plasma level: 63.8 ng/mL. Plasma t 1/2, terminal: 8.95 hr. Metabolized in the liver with unchanged drug (12%) and metabolites excreted through both the urine and feces.

Uses: Prevention of N&V; associated with initial and repeat cancer chemotherapy, including high-dose cisplatin. Prevention of N&V; associated with radiation, including total body irradiation and fractionated abdominal radiation. Investigational: Acute N&V; following surgery.

Contraindications: Known hypersensitivity to the drug.

Special Concerns: Use with caution during lactation. Safety and efficacy in children less than 2 years of age have not been established.

Side Effects: After IV use. CNS: Headache, somnolence, agitation, anxiety, CNS stimulation, insomnia, extrapyramidal syndrome. GI: Diarrhea, constipation, taste disorder. CV: Hypertension, hypotension, arrhythmias (e.g., sinus bradycardia, atrial fibrillation, AV block ventricular ectopy including nonsustained tachycardia, ECG abnormalities). Allergic: Hypersensitivity reactions (anaphylaxis) skin rashes. Miscellaneous: Asthenia, fever.
After PO use. CNS: Headache, dizziness, insomnia, anxiety, somnolence. GI: N&V;, diarrhea, constipation, abdominal pain. CV: Hypertension, hypotension, angina, atrial fibrillation, syncope (rare). Hypersensitivity: Rarely, hypersensitivity reactions; severe anaphylaxis shortness of breath, hypotension, urticaria. Miscellaneous: Fever, leukopenia, decreased appetite, anemia, alopecia, thrombocytopenia.

Laboratory Test Alterations: AST, ALT.

Drug Interactions: Because granisetron is metabolized by hepatic cytochrome P-450 drug-metabolizing enzymes, agents that induce or inhibit these enzymes may alter the clearance (and thus the half-life) of granisetron.

How Supplied: Injection: 1 mg/mL; Tablet: 2 mg

Dosage
?IV Antiemetic during cancer chemotherapy.
Adults and children over 2 years of age: 10 mcg/kg infused over 5 min beginning 30 min before initiation of chemotherapy.
Antiemetic following surgery.
1-3 mg.
?Tablets Protection from chemotherapy-induced N&V.;
Adults: 1 mg b.i.d. with the first 1 mg-tablet given 1 hr before chemotherapy and the second 1-mg tablet given 12 hr after the first tablet only on days chemotherapy is given. Alternatively, 2 mg once daily taken 1 hr before chemotherapy. Data are not available for PO use in children.
Protection from radiation-induced N&V.;
Adults: 2 mg once daily taken within 1 hr of radiation.