Object: For cancer chemotherapy with injection, oral agents are also frequently prescribed.  In checking injection prescriptions for cancer chemotherapy, mistakes in the prescription of oral agents have been found.  In this study, we analyzed inquiries for clarifying questionable points, and confirmed the importance of checking oral agents prescribed in cancer chemotherapy.
Methods: We investigated the following items between January and December 2006: the number of prescriptions in which the checking system for combined oral agents associated with cancer chemotherapy at the outpatient clinic was required, number of prescription errors regarding injection in which the prescription was changed based on inquiries for clarifying questionable points, and number of prescription errors regarding combined oral agents.  Furthermore, we classified precautions necessary for checking these prescriptions.
Results: From January to December 2006, the number of prescriptions was 5,132.  In 2,806 (54.7%) of them, it was necessary to check prescriptions for combined oral agents associated with chemotherapy.  The oral prescriptions were classified into 3types: agents described as pretreatment agents for chemotherapy in the package inserts, supportive therapy agents for reducing side effects, and oral anticancer agents.  There were 59 errors regarding injection, and 54 errors regarding combined oral agents.  Among the 54 errors, supportive therapy agents for reducing side effects comprised the highest percentage.
Conclusion: It was necessary to check prescriptions for oral agents in more than 50% of patients undergoing cancer chemotherapy at the outpatient clinic.  In addition, in cases in which adverse reactions could be avoided based on the inquiries, the percentage of injection errors was similar to that of oral preparation errors, confirming the importance of checking prescriptions for oral agents.