Evaluation of the risk factors for the failure of a single prophylactic dose of anticholinergic drugs for irinotecan-induced cholinergic symptoms.

Objective: Irinotecan (IRI) is an anticancer drug that is frequently used to treat colorectal, gastric, and pancreatic cancers. Its side effects include cholinergic symptoms, such as diarrhea, abdominal pain, nausea, and hyperhidrosis. Anticholinergic medicines are frequently used for treatment or prophylaxis; however, the risk factors for the failure of a single prophylactic anticholinergic administration remain unclear. Moreover, an appropriate anticholinergic drug for prophylaxis remains unknown. Thus, we aimed to identify the risk factors associated with the failure of a single prophylactic dose of anticholinergic drugs for IRI-induced cholinergic symptoms and to evaluate the usefulness of multiple prophylactic doses of anticholinergic drugs.

Materials and methods: Patients who underwent IRI treatment for colorectal, gastric, or pancreatic cancer and received prophylactic anticholinergic drugs for IRI-induced cholinergic symptoms (n = 135) were retrospectively evaluated. Univariate and multivariate logistic regression analyses were performed to identify the risk factors for failure of a single prophylactic dose of anticholinergic drugs. We also evaluated the efficacy of multiple prophylactic anticholinergic drug administration.

Results: Based on univariate and multivariate analyses, colorectal cancer, female sex, and prophylactic use of scopolamine butyl bromide were identified as risk factors for failure of a single prophylactic dose of anticholinergic drugs. The efficacy of multiple prophylactic doses was confirmed to be 95% of the patients who had a single prophylactic failure due to temporary effect but symptom appearance after a certain period of time (wearing-off).

Conclusion: We determined that colorectal cancer, female sex, and prophylactic use of scopolamine butyl bromide were risk factors associated with the failure of a single prophylactic dose of anticholinergic drugs, and that multiple prophylactic doses for wearing-off can be a promising method.