Irinotecan Mylan (Irinotecan Hydrochloride Trihydrate)

Irinotecan Mylan is a topoisomerase I inhibitor used in oncology for several cancer types.

• Metastatic colorectal cancer: improves overall survival when combined with fluoropyrimidine‑based regimens.
• Advanced solid tumors: provides antitumor activity in a range of refractory solid malignancies.
• Colorectal cancer (adjuvant setting): used as part of combination therapy to reduce recurrence risk after surgical resection.

• Irinotecan is a prodrug that is converted intracellularly to SN‑38, a potent inhibitor of topoisomerase I. By stabilizing the DNA‑topoisomerase I complex, it prevents relegation of single‑strand DNA breaks, leading to accumulation of DNA damage, inhibition of DNA replication, and ultimately cancer cell death.

Irinotecan may cause a range of adverse reactions, from mild to severe.

Common Side Effects

• Nausea and vomiting: gastrointestinal upset common during infusion.
• Diarrhea: may be severe and require antidiarrheal therapy.
• Neutropenia: reduced white blood cell count increasing infection risk.
• Alopecia: temporary hair loss during treatment.
• Fatigue: general tiredness and weakness.
• Anemia: decreased red blood cell levels causing fatigue.

Serious or Rare Side Effects

• Febrile neutropenia: fever with low neutrophils requiring urgent care.
• Severe colitis: inflammation of the colon that can be life‑threatening.
• Hepatotoxicity: liver enzyme elevations indicating liver injury.
• Hypersensitivity reactions: rash, bronchospasm, or anaphylaxis during infusion.
• Cardiac toxicity: rare arrhythmias or ischemic events.
• Secondary malignancies: very rare risk of new cancers after prolonged exposure.

Before initiating therapy, clinicians should assess patient health status and monitor for specific risks.

• Baseline blood counts: obtain CBC to detect pre‑existing neutropenia or anemia.
• Liver function: evaluate hepatic enzymes as irinotecan metabolism is hepatic.
• Renal function: adjust monitoring if creatinine clearance is impaired.
• Concomitant medications: review for drugs that may increase toxicity, especially CYP3A4 inhibitors.
• Pregnancy and lactation: avoid use unless benefits clearly outweigh potential fetal or infant risks.
• Store at ambient temperature: keep in original container, protect from light and moisture, and do not freeze.

Irinotecan can interact with several drug classes, altering efficacy or toxicity.

Major Interactions (Avoid)

• Strong CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin): may increase SN‑38 exposure and toxicity.
• CYP3A4 inducers (e.g., rifampin, carbamazepine): may reduce therapeutic effect.
• Anticholinergic agents: can exacerbate irinotecan‑induced diarrhea.

Moderate Interactions (Monitor Closely)

• Warfarin: may enhance anticoagulant effect, requiring INR monitoring.
• UGT1A1 inhibitors (e.g., atazanavir): can raise SN‑38 levels, increasing risk of neutropenia.
• Other myelosuppressive chemotherapy: may compound bone‑marrow suppression, necessitating frequent blood count checks.