Irinotecan Kabi (Irinotecan Hydrochloride Trihydrate)

Irinotecan is used in oncology to target cancers that rely on topoisomerase I activity.

• Metastatic colorectal cancer: improves overall response rates when combined with fluoropyrimidine‑based regimens.
• Advanced gastric cancer: used as part of combination chemotherapy to achieve tumor shrinkage.
• Pancreatic adenocarcinoma: incorporated into multi‑agent protocols to extend progression‑free survival.

• Irinotecan is a pro‑drug converted in vivo to SN‑38, a potent inhibitor of topoisomerase I. By stabilising the enzyme‑DNA cleavable complex, it prevents relegation of single‑strand DNA breaks, leading to accumulation of DNA damage, replication arrest, and ultimately apoptotic cell death in rapidly dividing tumor cells.

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

Common Side Effects

• Nausea and vomiting: gastrointestinal upset occurring during or after infusion.
• Diarrhea: often delayed, may require antidiarrheal therapy.
• Neutropenia: reduced white blood cell count increasing infection risk.
• Alopecia: temporary hair loss during treatment cycles.
• Fatigue: generalized tiredness affecting daily activities.

Serious or Rare Side Effects

• Severe neutropenic fever: high fever with low neutrophil count requiring urgent care.
• Acute cholinergic syndrome: abdominal cramps, sweating, and bradycardia.
• Hepatotoxicity: elevated liver enzymes indicating liver stress.
• Allergic reactions: rash, urticaria, or anaphylaxis in rare cases.

Before initiating Irinotecan therapy, clinicians should assess patient-specific risk factors and monitor laboratory parameters.

• Baseline blood counts: obtain CBC to detect pre‑existing neutropenia.
• Liver function: evaluate hepatic enzymes as Irinotecan metabolism is hepatic.
• Renal function: adjust monitoring for patients with impaired clearance.
• Concomitant medications: review for agents that may increase toxicity, such as CYP3A4 inhibitors.
• Pregnancy and lactation: avoid use unless benefits clearly outweigh potential fetal or infant risks.
• Store at 2-8°C: keep refrigerated, protect from light, do not freeze or shake.

Irinotecan interacts with several drug classes that can modify its efficacy or safety profile.

Major Interactions (Avoid)

• Strong CYP3A4 inhibitors (e.g., ketoconazole, ritonavir): may increase SN‑38 exposure and toxicity.
• UGT1A1 inhibitors (e.g., atazanavir): can elevate active metabolite levels, raising risk of neutropenia.
• Anticholinergic agents: may exacerbate cholinergic syndrome.

Moderate Interactions (Monitor Closely)

• Anticoagulants (e.g., warfarin): monitor INR as Irinotecan may affect coagulation.
• Myelosuppressive chemotherapy (e.g., carboplatin): increase risk of severe bone‑marrow suppression.
• Fluoropyrimidines (e.g., 5‑FU): require dose adjustments to manage overlapping toxicities.