Iritec (Irinotecan Hydrochloride Trihydrate)

Iritec is a chemotherapy agent that targets the topoisomerase I pathway in solid tumours, primarily colorectal cancer.

• Metastatic colorectal cancer: improves overall survival when used in standard regimens.
• Advanced colorectal cancer: provides disease control in patients who have progressed on prior therapy.
• Combination therapy for colorectal cancer: enhances the efficacy of fluoropyrimidine‑based regimens.

• Irinotecan is a pro‑drug that is 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, inhibition of replication and transcription, and ultimately cancer cell death.

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

Common Side Effects

• Diarrhea: may be severe and require supportive care.
• Nausea and vomiting: often managed with anti‑emetics.
• Neutropenia: reduced white blood cell count increasing infection risk.
• Alopecia: hair loss during treatment cycles.
• Fatigue: generalized tiredness.
• Anemia: decreased red blood cell count.

Serious or Rare Side Effects

• Febrile neutropenia: fever with low neutrophil count requiring urgent treatment.
• Severe colitis or intestinal perforation.
• Hypersensitivity reactions: rash, bronchospasm, or anaphylaxis.
• Hepatotoxicity: elevated liver enzymes or liver failure.
• Pulmonary toxicity: interstitial pneumonitis.
• Hemorrhagic cystitis: bladder inflammation with bleeding.

Before initiating Iritec, clinicians should consider several safety measures.

• Baseline blood counts: assess neutrophil and platelet levels.
• Liver function monitoring: evaluate transaminases and bilirubin.
• Renal function assessment: check creatinine clearance.
• Pregnancy and lactation: avoid use unless benefits outweigh risks.
• Concomitant infections: treat active infections before chemotherapy.
• Storage: Store at 2‑8°C: keep refrigerated, protect from light, do not freeze.

Iritec can interact with other medicines, altering its efficacy or toxicity.

Major Interactions (Avoid)

• Strong CYP3A4 inhibitors (e.g., ketoconazole): increase SN‑38 exposure.
• UGT1A1 inhibitors (e.g., atazanavir): raise risk of severe neutropenia.
• Live vaccines: may cause uncontrolled infection.

Moderate Interactions (Monitor Closely)

• Other myelosuppressive agents: cumulative bone‑marrow suppression.
• Anticoagulants (warfarin, DOACs): heightened bleeding risk.
• Antidiarrheal agents (loperamide): may mask early signs of severe diarrhea.
• Proton pump inhibitors: possible alteration of gastric pH affecting absorption of oral supportive drugs.