Evaluating eGFR without body surface area adjustment (individualized eGFR) is recommended as a renal function measure while checking prescriptions at community pharmacies. However, it is considered that estimated creatinine clearance (estimated CCr) is less likely to be overestimated than the individualized eGFR and may increase prediction accuracy in patients with frailty/sarcopenia, which is common in late-stage elderly people. However, body surface area-adjusted eGFR (standardized eGFR) values are often used in out-of-hospital prescriptions. Moreover, in several cases, renal function evaluation is difficult for patients whose prescriptions do not include any laboratory values. In this study, we attempted to calculate index values of weight and age to identify late-stage elderly people who should be cautious about prescription checking of renal excretion drugs.

Among 1,026 late-stage elderly people with a standardized eGFR of ≥40 mL/min/1.73m² who brought prescriptions issued by Asukai Hospital to Sukoyaka Pharmacy between March and August 2019 and had serum creatinine (Cr)/weight data in the clinical records of Asukai Hospital. We calculated weight/age index values using receiver operating characteristic curves for patients whose estimated CCr was <40 mL/min (42 men and 121 women); the results were found to be ≤51.9 kg/≥83 years for men and ≤48.6 kg/≥84 years for women.

When verified in patients with an eGFR of ≥40 mL/min/1.73m² from other institutions, all estimated CCrs outside the weight/age criteria group (mean ± SE (mL/min): men 57.0 ± 2.4, women 66.5 ± 5.4) were ≥40 mL/min, which was significantly higher than those in the weight/age criteria group (mean ± SE (mL/min): men 43.9 ± 4.4, women 39.5 ± 3.9).

Therefore, it is likely that the estimated CCr of the late-stage elderly people whose weight/age index values correspond those determined in this study will be <40mL/min. Furthermore, we believe that some approaches, such as the use of prescription questions and tracing reports, are necessary when the dose of renal excretion drug is considered inappropriate, even if the renal function is unknown.

The use of CKD stickers has been attempted, with the aim of providing patients with effective and safe medication by sharing information about their kidney function in various parts of Japan. While there are surveys on the need for CKD stickers by hospitals/ community pharmacies, what patients understand regarding the necessity of sharing information about their kidney function remains unclear. We constructed a system of attaching CKD stickers in Fujinomiya City and conducted a survey on the needs of patients who attached the sticker at Fujinomiya City General Hospital and the problem of sharing information about patients’ kidney function in the city area. We obtained informed consent from all 228 patients to whom we proposed attaching a CKD sticker on their medication notebook during a period of three months starting from July 10, 2019. There were 62 (27%) patients who attached them based on a protocol prepared with the help of physicians. We received responses to the questionnaire from 67 out of 74 patients, including inpatients, patients participating in a kidney disease education program, hemodialyzed outpatients (G3b/G4/G5/G5D=7/12/11/37, response rate: 91%), and 19 of 20 community pharmacists who had attended a workshop on kidney disease medication (response rate: 95%). Fifty-one (76%) patients had an experience of receiving drugs at an insurance-funded community pharmacy. Of them, only 20% (n =10) gave information on their kidney function, while only 29% (n =15) were asked about their kidney function by a community pharmacist. In contrast, 16 (84%) community pharmacists checked patients’ kidney function only when test results were available. The proportion of patients recognizing that drugs are adjusted based on kidney function was low (43%, n =29), and all the patients and community pharmacists answered that they expected the attachment of CKD stickers to be started. The ways of utilizing CKD stickers by community pharmacists included not only checking the dosage of the regimen but also communicating with patients and guiding their lifestyle. Patients poorly recognized that community pharmacists needed information about patients’ kidney function, and this information was not shared. The survey results suggested not only that CKD stickers may lead to the optimization of medication but also that explaining the significance of sharing information about patients’ kidney function with community pharmacies and getting the understanding of patients might lead to better utilization of medication notebooks with CKD stickers attached and guide the medical treatment for kidney disease by pharmacists.

We report the case of a patient with Gitelman syndrome (GS) in which hypokalemia was exacerbated by the combination of adrenaline β₂ agonist and theophylline, and drug-induced QT prolongation occurred. A woman in her twenties was prescribed tulobuterol patches, theophylline and clarithromycin (CAM), and so on for an acute upper respiratory infection. After taking these medications, she developed increasing fatigue and weakness of the limbs, which was aggravated with prolonged usage. Upon admission to the Suita Tokushukai Hospital, hypokalemia (2.3 mEq/L) and QT prolongation (QTc, 0.523 sec) were detected. On the basis of physical findings and blood tests, it was inferred that the hypokalemia was attributed to GS, which was exacerbated by the combination of adrenaline β₂ agonist and theophylline. Additionally, it was suspected that CAM had contributed to the development of the prolonged QT interval. After discontinuance of all medications, the QT prolongation resolved. For GS, she has still been taking potassium agent even after she is discharged. Hypokalemia can result from a variety of causes, including drugs, and may lead to QT prolongation and other arrythmias. Thus, on the basis of our experience with this case, we developed a hypokalemia initiative, described herein.