Kytril (granisetron hydrochloride) is a potent 5-HT3 receptor antagonist specifically formulated for the prevention and management of nausea and vomiting associated with emetogenic cancer chemotherapy and radiotherapy. It is a cornerstone of modern antiemetic prophylaxis, offering reliable and sustained control over acute and delayed phases of chemotherapy-induced nausea and vomiting (CINV). Its targeted mechanism provides a critical layer of support for patients undergoing aggressive treatment regimens, helping to maintain nutritional status, hydration, and overall quality of life during a challenging therapeutic journey. Available in intravenous and oral formulations, Kytril integrates seamlessly into both inpatient and outpatient oncology protocols.

Features

• Active ingredient: Granisetron hydrochloride
• Available formulations: Injectable solution (1 mg/mL), tablets (1 mg)
• Mechanism: Selective antagonist of serotonin 5-HT3 receptors
• Onset of action: Rapid, with effects typically noted within minutes of IV administration
• Duration: Provides protection for up to 24 hours following a single dose
• Compatibility: Can be administered with most common IV fluids and other supportive medications

Benefits

• Superior Emetic Control: Demonstrates high efficacy in preventing acute and delayed nausea and vomiting following moderately to highly emetogenic chemotherapy.
• Flexible Dosing Options: Availability of both IV and oral forms allows for tailored antiemetic strategies, including switch therapy and outpatient management.
• Favorable Safety Profile: Generally well-tolerated, with a low incidence of severe adverse events, supporting its use across diverse patient populations.
• Reduced Need for Rescue Medication: Effective primary prophylaxis decreases the requirement for additional antiemetic agents, simplifying the treatment regimen.
• Supports Treatment Adherence: By mitigating one of the most distressing side effects of chemotherapy, it helps patients remain committed to their prescribed cancer treatment cycles.
• Minimal Sedation: Unlike some older antiemetics, it does not typically cause significant drowsiness, allowing patients to maintain daily activities.

Common use

Kytril is primarily indicated for the prevention and treatment of nausea and vomiting induced by cancer chemotherapy, including both highly emetogenic agents (e.g., cisplatin, carboplatin, cyclophosphamide) and moderately emetogenic regimens. It is also used in the management of radiation-induced nausea and vomiting, particularly following total body irradiation or abdominal radiation. In postoperative settings, it may be employed off-label for the prevention of postoperative nausea and vomiting (PONV), though this is not its primary licensed indication.

Dosage and direction

Injectable Solution:
For chemotherapy-induced nausea and vomiting: 10 mcg/kg (or 1 mg fixed dose) administered intravenously over 5 minutes, beginning within 30 minutes prior to chemotherapy. Administration may be repeated every 24 hours as needed.
For radiotherapy-induced nausea and vomiting: 2 mg orally once daily or 1 mg twice daily.

Tablets:
For chemotherapy-induced nausea and vomiting: 2 mg orally once daily or 1 mg twice daily, with the first dose administered up to 1 hour before chemotherapy.
For radiotherapy-induced nausea and vomiting: 2 mg once daily within 1 hour of radiotherapy.

Dosage may be adjusted based on clinical response, emetogenic potential of the regimen, and patient-specific factors. It is not recommended for use in children under 2 years of age.

Precautions

• Use with caution in patients with known hypersensitivity to other 5-HT3 receptor antagonists.
• Electrolyte imbalances (e.g., hypokalemia, hypomagnesemia) should be corrected prior to administration, as they may exacerbate nausea or arrhythmia risk.
• Patients with congenital long QT syndrome or those taking other QT-prolonging drugs should be monitored; consider ECG in at-risk populations.
• Hepatic impairment does not usually require dose adjustment, but severe impairment warrants careful observation.
• Not intended for the treatment of established nausea and vomiting; it is prophylactic in nature.

Contraindications

• Hypersensitivity to granisetron or any component of the formulation.
• Concomitant use with apomorphine due to risk of profound hypotension and loss of consciousness.
• History of severe cardiac arrhythmias or uncompensated heart failure where QT prolongation would pose significant risk.

Possible side effect

The most commonly reported side effects are generally mild and transient. These may include:

• Headache (14–21%)
• Constipation (3–18%)
• Asthenia (5–18%)
• Diarrhea (4–9%)
• Abdominal pain (2–6%)
• Dyspepsia (1–5%)

Less frequently, transient elevations in liver transaminases, dizziness, insomnia, and anxiety have been reported. Serious but rare adverse events include hypersensitivity reactions (e.g., anaphylaxis), serotonin syndrome (especially when used with other serotonergic drugs), and QT interval prolongation.

Drug interaction

• Serotonergic drugs (e.g., SSRIs, SNRIs, tramadol, MAO inhibitors): Increased risk of serotonin syndrome.
• Drugs that prolong QT interval (e.g., certain antiarrhythmics, antipsychotics, antibiotics): Additive effect on QT prolongation; monitor ECG.
• Apomorphine: Contraindicated due to risk of hypotension and CNS depression.
• Enzymes inducers/inhibitors: Granisetron is metabolized primarily by CYP3A4; potent inducers (e.g., rifampin) may reduce efficacy, while inhibitors (e.g., ketoconazole) may increase exposure.

Missed dose

If a dose is missed, it should be taken as soon as remembered unless it is nearly time for the next scheduled dose. Do not double the dose. For prophylactic use prior to chemotherapy, if the pre-chemo dose is missed, administer as soon as possible, even if chemotherapy has already begun.

Overdose

Symptoms of overdose may include severe headache, dizziness, blurred vision, hypotension, and ECG changes (including QT prolongation). There is no specific antidote. Treatment is supportive and symptomatic, including monitoring of vital signs and ECG. Hemodialysis is unlikely to be effective due to high protein binding.

Storage

Store at controlled room temperature (20–25°C or 68–77°F). Protect from light. Do not freeze. Keep out of reach of children. The injectable solution should be inspected visually for particulate matter and discoloration prior to administration.

Disclaimer

This information is intended for healthcare professionals and should not replace professional medical advice, diagnosis, or treatment. Always consult the full prescribing information and clinical guidelines before administration. Dosage and indications may vary based on regional approvals and individual patient factors.

Reviews

“Kytril has been a mainstay in our oncology unit for over a decade. Its reliability in preventing CINV, especially with high-dose cisplatin, is exceptional. We appreciate the flexibility of IV and oral formulations, which supports smooth transitions for our outpatient population.” — Medical Oncologist, University Hospital

“In comparative studies, granisetron demonstrates non-inferiority to other 5-HT3 antagonists with a favorable side effect profile. The once-daily dosing for many regimens supports adherence and simplifies nursing administration.” — Oncology Pharmacist, Comprehensive Cancer Center

“Patient feedback consistently highlights the effectiveness of Kytril in reducing the distress associated with chemotherapy. The low incidence of sedation is particularly valued, as it allows individuals to remain functional during treatment.” — Oncology Nurse Practitioner, Ambulatory Care Center