Home Drug Guide Irinotecan Hydrochloride

Drug Guide

Generic Name

Irinotecan Hydrochloride

Brand Names Camptosar, Onivyde

Classification

Therapeutic: Antineoplastic agent

Pharmacological: Topoisomerase I inhibitor

FDA Approved Indications

  • Colorectal cancer (metastatic)
  • Pancreatic adenocarcinoma (Onivyde)

Mechanism of Action

Irinotecan inhibits topoisomerase I, an enzyme involved in DNA replication. By stabilizing the DNA-topoisomerase I complex, it prevents DNA unwinding and replication, leading to cell death.

Dosage and Administration

Adult: Dose varies by indication and regimen; typically administered IV every 3 weeks or weekly, with supportive medications.

Pediatric: Pregnancy category D; limited data in pediatrics, use with caution.

Geriatric: Adjust dose based on functional status and comorbidities.

Renal Impairment: Adjust dose in severe renal impairment.

Hepatic Impairment: Adjust dose; avoid in severe hepatic impairment.

Pharmacokinetics

Absorption: Administered IV, so absorption is complete.

Distribution: Wide distribution, crosses blood-brain barrier minimally.

Metabolism: Primarily hepatic via carboxylesterases to active metabolite SN-38.

Excretion: Fecal and renal routes.

Half Life: Approximately 3-4 days for the active metabolite SN-38.

Contraindications

  • Hypersensitivity to irinotecan or mannitol (used in formulation).
  • Severe urinary or hepatic impairment.

Precautions

  • Use with caution in immunosuppressed patients, as it causes myelosuppression.
  • Monitor for severe diarrhea, neutropenia, and hepatotoxicity.
  • Pregnancy risk category D; use effective contraception during treatment.

Adverse Reactions - Common

  • Neutropenia (Common)
  • Diarrhea (Common)
  • Alopecia (Common)
  • Nausea and vomiting (Common)

Adverse Reactions - Serious

  • Severe neutropenia leading to infection (Serious)
  • Severe diarrhea leading to dehydration and electrolyte imbalance (Serious)
  • Mucositis (Serious)
  • Liver toxicity (Serious)

Drug-Drug Interactions

  • Rifampin (may decrease irinotecan levels),
  • Ciprofloxacin (may increase levels of SN-38)
  • Other myelosuppressive agents

Drug-Food Interactions

  • Grapefruit juice (may alter metabolism)

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor complete blood counts, liver function tests, and renal function.

Diagnoses:

  • Risk for infection (neutropenia)
  • Fluid volume deficit (diarrhea)
  • Imbalanced nutrition (anorexia)

Implementation: Administer IV as prescribed, premedicate with antiemetics, monitor for signs of toxicity, manage diarrhea proactively.

Evaluation: Assess blood counts, hepatic and renal function regularly, evaluate patient’s response and side effects.

Patient/Family Teaching

  • Report any signs of infection, severe diarrhea, or dehydration.
  • Use effective contraception during and for at least 6 months after treatment.
  • Maintain hydration and nutritional support.
  • Follow-up laboratory tests as scheduled.

Special Considerations

Black Box Warnings:

  • Severe myelosuppression and diarrhea can be life-threatening.
  • Monitor closely for early signs and intervene promptly.

Genetic Factors: UGT1A1 *28/*28 genotype increases risk of severe neutropenia and diarrhea.

Lab Test Interference: May cause transient elevations in liver enzymes; monitor accordingly.

Overdose Management

Signs/Symptoms: Severe myelosuppression, diarrhea, dehydration.

Treatment: Supportive care, including hospitalization, IV fluids, antibiotics for infection, and possibly use of hematopoietic growth factors.

Storage and Handling

Storage: Store at room temperature, protected from light.

Stability: Stable under recommended storage conditions for the duration specified in the package insert.

🛡️ 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.