Home Drug Guide Granisetron

Drug Guide

Generic Name

Granisetron

Brand Names Sancuso, Sustol

Classification

Therapeutic: Anti-nausea and antiemetic

Pharmacological: 5-HT3 receptor antagonist

FDA Approved Indications

  • Prevention of nausea and vomiting associated with chemotherapy and radiotherapy

Mechanism of Action

Granisetron works by selectively blocking serotonin 5-HT3 receptors in the central and peripheral nervous systems, thereby reducing nausea and vomiting signals.

Dosage and Administration

Adult: Sancuso: Transdermal patch applied once weekly, typically 3 hours before chemotherapy. Sustol: Subcutaneous injection usually 2 mg 30 minutes before chemotherapy.

Pediatric: Use and dosing in pediatric patients are not well established; consult specialized guidelines.

Geriatric: Adjustments generally not required but monitor for increased sensitivity.

Renal Impairment: No specific adjustment required.

Hepatic Impairment: Use with caution; no specific dose adjustment established.

Pharmacokinetics

Absorption: Rapid absorption following transdermal application (Sancuso) and subcutaneous injection (Sustol).

Distribution: Widely distributed, crosses the blood-brain barrier.

Metabolism: Metabolized primarily in the liver via CYP3A4, CYP1A2, and CYP2D6.

Excretion: Excreted mainly in urine and feces.

Half Life: Approximately 8 hours (oral and IV forms); transdermal provides sustained release over 7 days.

Contraindications

  • Known hypersensitivity to granisetron or other 5-HT3 receptor antagonists.

Precautions

  • Use with caution in patients with a history of arrhythmias, QT prolongation, or concomitant QT-prolonging drugs.

Adverse Reactions - Common

  • Headache (Common)
  • Constipation (Common)
  • Mild dizziness (Common)

Adverse Reactions - Serious

  • QT prolongation leading to arrhythmias (e.g., Torsades de Pointes) (Rare)
  • Serotonin syndrome (when combined with other serotonergic drugs) (Rare)

Drug-Drug Interactions

  • Caution with other QT-prolonging agents (e.g., certain antidepressants, antiarrhythmics).

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Assess for baseline cardiac status, especially QT interval before administration.

Diagnoses:

  • Risk of cardiac dysrhythmias

Implementation: Administer as per prescribed route; monitor ECG if indicated; observe for signs of arrhythmias.

Evaluation: Evaluate for reduction in nausea and vomiting; monitor for adverse effects.

Patient/Family Teaching

  • Report any signs of arrhythmias (palpitations, dizziness, fainting).
  • Follow application instructions for transdermal patches.
  • Avoid other QT-prolonging drugs without medical advice.

Special Considerations

Black Box Warnings:

  • QT prolongation and serious arrhythmias are rare but serious.

Genetic Factors: No specific genetic factors impacting use but consider pharmacogenetic testing for CYP3A4 metabolized drugs if relevant.

Lab Test Interference: None noted.

Overdose Management

Signs/Symptoms: Serious CNS effects such as agitation, confusion, hallucinations; potential arrhythmias.

Treatment: Supportive care; manage symptoms; correct arrhythmias; activated charcoal if ingestion is recent.

Storage and Handling

Storage: Store at room temperature away from light and moisture.

Stability: Stable for the duration of the recommended shelf life.

🛡️ 5 Critical Medication Safety Tips for Nurses

1

Triple-Check High-Risk Medications

Always have another nurse verify insulin, heparin, warfarin, and chemotherapy drugs. These "high-alert" medications cause the most serious errors. Check concentration, dose calculation, and pump settings twice.

2

Know Look-Alike, Sound-Alike Drugs

Common mix-ups: hydromorphone/morphine, Celebrex/Celexa, Zyprexa/Zyrtec. Always use BOTH generic and brand names, read labels twice, and use barcode scanning when available. One wrong letter can be fatal.

3

Assess Before AND After Giving Meds

Check vitals before cardiac meds, pain levels before analgesics, and blood glucose before insulin. Always reassess within 30 minutes to evaluate effectiveness and watch for adverse reactions.

4

Watch for Drug Interactions

Common dangerous combinations: warfarin + aspirin (bleeding), ACE inhibitors + potassium (hyperkalemia), digoxin + diuretics (toxicity). Always check drug interactions before administering new medications.

5

Educate Your Patients

Teach patients medication names, purposes, major side effects, and what to report. Informed patients catch errors and improve compliance. Always encourage questions - an educated patient is a safer patient.

⚡ Remember: When in doubt, don't give it out! It's always safer to double-check than regret later.

⚠️ Medical Disclaimer

This drug guide is for educational purposes only and is NOT intended for clinical use. Always consult current prescribing information, healthcare providers, and institutional protocols before administering any medication. Do not use this information for patient care decisions.