Which of the following is a common cause of diarrhea?

Irinotecan is a widely recognized cause of diarrhea, particularly due to its mechanism of action and how it interacts with the gastrointestinal system. It is a topoisomerase inhibitor primarily used in the treatment of colorectal cancer, and one of its notable side effects is diarrhea, which can vary from mild to severe.

The underlying reason for this side effect is that irinotecan can cause intestinal mucosal irritation and alter gut motility. In particular, it may lead to a condition known as "early diarrhea," which can occur within the first 24 hours after administration due to the release of a metabolite called SN-38. This metabolite can affect the epithelial cells in the gut, resulting in increased fluid secretion and decreased absorption, leading to diarrhea.

Other medications listed, while having their own side effects, do not share the same level of association with diarrhea as irinotecan. For example, vinorelbine is more commonly associated with neutropenia and constipation, thalidomide has been linked to peripheral neuropathy and sedation, and bortezomib is often related to side effects like thrombocytopenia and fatigue, not diarrhea. Thus, when considering the side effects profile, irinotecan stands out as the agent most commonly