What is the main adverse effect associated with irinotecan?

Irinotecan is a chemotherapeutic agent commonly used in the treatment of various cancers, particularly colorectal cancer. One of the main adverse effects associated with irinotecan is early onset diarrhea, which can occur shortly after administration of the drug. This type of diarrhea is often related to the infusion of the drug and is due to its mechanism of action, which includes inhibition of the enzyme topoisomerase I, leading to damage in the gastrointestinal tract.

Early onset diarrhea typically occurs within 24 hours of treatment and is known to be dose-dependent. It can be a significant issue for patients, as it may lead to dehydration and require additional management strategies, including the use of loperamide or other antidiarrheal medications. Recognizing this side effect is crucial for effective patient management during chemotherapy treatment with irinotecan, as prompt intervention can help mitigate the severity of the diarrhea and enhance the patient's overall comfort and treatment adherence.