Irinotecan Accord (Irinotecan Hydrochloride Trihydrate)

Irinotecan is a topoisomerase I inhibitor used in colorectal cancer treatment pathways.

• Metastatic colorectal cancer: improves disease control and overall survival when combined with standard chemotherapy regimens.
• Adjuvant therapy for colon cancer: reduces risk of recurrence after surgical resection in patients with high‑risk disease.

• Irinotecan is converted intracellularly to its active metabolite SN‑38, which binds to the DNA‑topoisomerase I complex and stabilizes it. This prevents the re‑ligation of single‑strand DNA breaks during replication, leading to accumulation of DNA damage, replication arrest, and ultimately tumor cell death.

Irinotecan may cause a range of adverse reactions that vary in frequency and severity.

Common Side Effects

• Diarrhea: often delayed and may be severe.
• Neutropenia: reduced white blood cell count increasing infection risk.
• Nausea and vomiting: typical chemotherapy‑related symptoms.
• Fatigue: generalized tiredness during treatment cycles.
• Alopecia: hair thinning or loss.
• Anorexia: decreased appetite.

Serious or Rare Side Effects

• Febrile neutropenia: fever with low neutrophil count requiring urgent care.
• Severe colitis: life‑threatening intestinal inflammation.
• Cholinergic syndrome: abdominal cramping, sweating, and bradycardia.
• Hypersensitivity reactions: rash, bronchospasm, or anaphylaxis.
• Hepatic dysfunction: elevated liver enzymes or jaundice.
• Thromboembolic events: rare clot formation in veins or arteries.

Before initiating therapy, clinicians should assess patient suitability and monitor for potential complications.

• Hematology monitoring: perform baseline and periodic complete blood counts.
• Liver function assessment: evaluate hepatic enzymes and bilirubin before each cycle.
• Dose adjustment: modify dosing in patients with moderate hepatic impairment.
• Diarrhea management: implement prophylactic antidiarrheal measures and educate patients on early reporting.
• Pregnancy and lactation: avoid use unless benefits outweigh potential risks; consult obstetric specialist.
• Store at 2-8°C: keep refrigerated, protect from light, do not freeze or shake the vial.

Irinotecan can interact with other medicines, affecting its safety or efficacy.

Major Interactions (Avoid)

• Strong CYP3A4 inducers (e.g., rifampin, carbamazepine): may reduce SN‑38 exposure and therapeutic effect.
• UGT1A1 inhibitors (e.g., atazanavir, indinavir): increase SN‑38 levels, raising toxicity risk.
• Concurrent myelosuppressive agents: amplify risk of severe neutropenia and infection.

Moderate Interactions (Monitor Closely)

• Anticoagulants (e.g., warfarin): enhanced bleeding risk due to mucosal injury.
• Anticholinergic drugs: may exacerbate cholinergic syndrome symptoms.
• Other anti‑diarrheal agents: adjust dosing to avoid excessive constipation or ileus.