Dose Adjustment of Renaly Excreted Drugs by Pharmacists Using a Self-check Serum Creatinine Testing Machine in Elderly Subjects

Abstract

Most elderly people have a decreased glomerular filtration rate (GFR) as an indicator of renal function with increasing age, even if serum creatinine（ S-Cr） is within normal range. The decreased renal function of elderly people causes adverse reactions to increase the blood concentration of renaly excreted drugs. If pharmacists working in community pharmacies could simply and quickly evaluate renal function in elderly people who had been administrated renaly excreted drugs, they could help prevent adverse reactions and suggest an optimal dosage for doctor to prescribe, who have not received an evaluation of renal function in hospital and who do not bring laboratory examination results to a pharmacy. We practiced self-check of S-Cr in a long-term care health facility in preparation for practice in pharmacy.. We examined the prescriptions of 92 subjects, of who 22 subjects who were administered renaly excreted drugs practiced self-check of S-Cr. We estimated renal function (creatinine clearance: CCr) to measure S-Cr to collect blood from the prick of a finger with using of self-check S-Cr testing machine, Stat Sensor -I® (Nova Biomedical Inc). We examined the availability of self-check S-Cr test and relation between renal function and actual prescription of renaly excreted drugs for elderly people. The self-check of S-Cr via use of the Stat Sensor –I® was useful to estimate the renal function simply and quickly with the guidance of a pharmacist. Though S-Crs were in the normal range, elderly subjects of CCr less than 50 mL/min were 11 of 12 subjects (91.7%). 5 out of 22 subjects of the elderly subjects needed a reduction in dose (22.7%). These dosage for all subjects were reduced to approach a reduction of dose to prescribing doctor. S-Cr was not much examined in elderly patients, and even if examined, it was not used in elderly patients to adjust the optimal dosage as to renal function to calculate CCr or GFR. Many elderly patients had decreased renal function requiring a dose adjustment of renaly excreted drug. It is thought that among elderly patients taking renaly excreted drugs are absolutely necessary to estimate the renal function. In conclusion, we believe that self-check of S-Cr that can determine renal function simply and quickly is useful to adjust the dose of renaly excreted drugs. Further, we also believe that pharmacists working in community pharmacies could help prevent the adverse reactions through the use of the self-check of S-Cr in elderly patients.