Irinotekan Teva (Irinotecan Hydrochloride)

Irinotecan is a chemotherapy agent used in the treatment of colorectal cancer and related disease states.

• Metastatic colorectal cancer: administered as part of combination regimens to improve overall survival.
• Advanced colorectal adenocarcinoma: used to reduce tumor burden and delay disease progression.
• Colorectal cancer (adjuvant setting): given after surgery to lower the risk of recurrence.

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

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

Common Side Effects

• Diarrhea: often severe and may require supportive care.
• Nausea and vomiting: typical chemotherapy‑related gastrointestinal upset.
• Neutropenia: reduced white blood cell count increasing infection risk.
• Fatigue: generalized tiredness during treatment.

Serious or Rare Side Effects

• Febrile neutropenia: fever with low neutrophil count, a medical emergency.
• Severe colitis: intense inflammation of the colon leading to dehydration.
• Hepatotoxicity: elevated liver enzymes or jaundice.
• Allergic reactions: rash, bronchospasm, or anaphylaxis in rare cases.

Before initiating therapy, clinicians should evaluate patient‑specific factors and monitor for toxicity.

• Dose adjustment: consider renal or hepatic impairment when determining the appropriate dose.
• Baseline labs: obtain complete blood count and liver function tests prior to each cycle.
• Infection risk: advise patients to report fever or signs of infection promptly.
• Pregnancy and lactation: avoid use unless the potential benefit justifies the potential risk to the fetus or infant.
• Store at ambient temperature: keep in the original container, protect from light and moisture, and do not freeze.

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

Major Interactions (Avoid)

• Strong UGT1A1 inhibitors (e.g., atazanavir): may increase SN‑38 exposure and toxicity.
• Concurrent use of potent CYP3A4 inhibitors (e.g., ketoconazole): can raise irinotecan plasma levels.
• Live vaccines: immunosuppression may reduce vaccine effectiveness and increase infection risk.

Moderate Interactions (Monitor Closely)

• CYP3A4 inducers (e.g., rifampin): may lower drug concentrations, reducing efficacy.
• Other myelosuppressive agents: combined effect can exacerbate neutropenia.
• Radiation therapy: concurrent treatment may increase gastrointestinal toxicity.