Background The incidence of renal impairment is increasing in cancer patients as patients are getting older and more aggressive treatments become available for this population. For those drugs in which renal excretion is an important determinant in elimination, dose adjustment is often required if renal function is impaired. ‘CS rules’ is a cognitive clinical decision support system (CDSS) designed to assist clinical pharmacists in making dosing adjustments for individual patients.

Purpose To optimise cytotoxic drug dosing in outpatient cancer patients with renal impairment.

Material and methods For a period of 6 months, a pilot was performed with the CDSS to optimise chemotherapy in patients with renal failure in the outpatient setting. Clinical rules were defined for 11 cytotoxic drugs used in the outpatient setting, for which dose reduction is required if renal function is impaired, according to the guidelines. The CDSS was run overnight and alerts were generated on all active electronic medication orders with chemotherapeutics using the most recent creatinine value. Rules were generated during the whole period that a chemotherapeutic agent was used, independently of doctor or pharmacy visits. Alerts were analysed by the pharmacist in the outpatient pharmacy of the hospital. If a dose reduction seemed necessary, the oncologist was contacted by the pharmacist and the necessity of a dose reduction or modification was discussed.

Results During the pilot period, the investigated chemotherapeutics were prescribed to 232 cancer patients. The 11 clinical rules generated alerts for 33 patients with impaired renal function. Overall, these alerts resulted in an intervention by the clinical pharmacist about dose reduction due to impaired renal function in 9.1% of patients.

Conclusion Identification of patients at risk helps the pharmacist and oncologist to optimise drug therapy in cancer patients with renal dysfunction in the outpatient setting. The ‘impaired renal function’ alerts resulted in valuable interventions by the pharmacist. This study showed that a CDSS can effectively be used in an outpatient pharmacy practice to select patients at risk of cytotoxic drug overdose due to renal impairment with continuous surveillance independently of new drug dispensing in the pharmacy or a doctor visit.

No conflict of interest