Home Drug Guide Granisetron Hydrochloride

Drug Guide

Generic Name

Granisetron Hydrochloride

Brand Names Kytril, Granisetron Hydrochloride Preservative Free, Granisol

Classification

Therapeutic: Antiemetic

Pharmacological: Serotonin 5-HT3 receptor antagonist

FDA Approved Indications

  • Prevention of chemotherapy-induced nausea and vomiting (CINV)
  • Prevention of radiation therapy-induced nausea and vomiting

Mechanism of Action

Granisetron selectively antagonizes serotonin (5-HT3) receptors both centrally in the chemoreceptor trigger zone and peripherally on vagal nerve terminals in the gastrointestinal tract, thereby blocking the vomiting reflex pathway.

Dosage and Administration

Adult: Typically 1 mg administered intravenously 30 minutes prior to chemotherapy or radiation; can be repeated every 8 hours as needed, up to a total of 2 mg per day.

Pediatric: Dosage varies based on age and weight; usually 10 mcg/kg IV administered 30 minutes prior to chemotherapy, with additional doses as needed.

Geriatric: No specific dosage adjustment is usually required; monitor for increased sensitivity.

Renal Impairment: No dose adjustment necessary for mild to moderate impairment; severe impairment requires cautious use.

Hepatic Impairment: No specific adjustment recommended.

Pharmacokinetics

Absorption: Rapidly absorbed after oral administration; bioavailability approximately 60%.

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

Metabolism: Metabolized primarily in the liver via oxidation by cytochrome P450 enzymes.

Excretion: Excreted mainly in urine (approximately 74%), with some fecal excretion.

Half Life: Approximately 2-4 hours.

Contraindications

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

Precautions

  • Use cautiously in patients with prior history of arrhythmias or those taking medications that prolong QT interval.
  • Report any signs of hypersensitivity or adverse reactions promptly.
  • Pregnancy category B; should be used during pregnancy only if clearly needed.
  • Lactation: Because of potential for adverse effects, use with caution.

Adverse Reactions - Common

  • Headache (Common)
  • Constipation (Common)
  • Dizziness (Common)

Adverse Reactions - Serious

  • QT prolongation, Torsades de Pointes (Rare)
  • Serious hypersensitivity reactions (Rare)

Drug-Drug Interactions

  • Medications prolonging QT interval (e.g., amiodarone, sotalol)
  • Other serotonergic drugs which may increase risk of serotonin syndrome

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor for efficacy in controlling nausea/vomiting; observe cardiac status, especially QT interval if on other QT-prolonging drugs.

Diagnoses:

  • Risk for electrolyte imbalance due to vomiting
  • Risk for arrhythmias

Implementation: Administer per prescription, preferably 30 minutes before chemotherapy or radiation;

Evaluation: Assess patient's nausea/vomiting control and monitor for adverse effects.

Patient/Family Teaching

  • Take medication exactly as prescribed.
  • Report any abnormal heartbeat, dizziness, or fainting.
  • Notify healthcare provider if you experience headache or constipation.
  • Avoid use of other serotonergic medications unless directed by healthcare provider.

Special Considerations

Black Box Warnings:

  • QT prolongation and arrhythmia risk

Genetic Factors: None specifically identified.

Lab Test Interference: None noted.

Overdose Management

Signs/Symptoms: Severe bradycardia, hypotension, arrhythmias, CNS disturbances.

Treatment: Supportive care; monitor cardiac function; activated charcoal may be considered if ingestion is recent.

Storage and Handling

Storage: Store at 20-25°C (68-77°F), protected from light and moisture.

Stability: Stable under recommended storage conditions; discard expired medications.

🛡️ 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.