Sodium-glucose co-transporter 2 (SGLT2) inhibitors exhibit an insulin-independent antihyperglycemic effect and are used as therapeutic agents for the treatment of diabetes. Recently, they have been shown to exert additional effects, such as prevention of heart failure and protection of renal function. Specifically, empagliflozin (10 mg) has been used to treat chronic heart failure even in patients without diabetes. However, SGLT2 inhibitors are associated with natriuresis and osmotic diuresis, and the Japan Association for Diabetes Society made a series of recommendations regarding the proper use of these drugs. In this study, we investigated the use of empagliflozin for the treatment of heart failure and examined how pharmacists should be involved for its proper use. The ages and values of laboratory tests of patients who were prescribed empagliflozin for either the treatment of heart failure (heart failure group, n=15) or diabetes (diabetic group, n=19) were compared. The median age was considerably higher in the heart failure than in the diabetic group (76.4 ± 11.6 vs 57.7 ± 14.3 years). In contrast, HbA1c was markedly lower value in the heart failure than in the diabetic group (6.9% ± 1.0 vs 9.0% ± 1.6). Additionally, estimated glomerular filtration rate (eGFR) was substantially lower value in the heart failure than in the diabetic group (52.1 ± 17.6 vs 74.6 ± 24.6 mL/min/1.73m2). Blood levels of sodium (Na) and potassium (K) were significantly lower value in the heart failure than in the diabetic group, although both were within normal limits (Na: 138.4 ± 0.83 vs 139.7 ± 2.1 mmol/L; K: 4.0 ± 0.59 vs 4.4 ± 0.25 mmol/L). When empagliflozin is prescribed for the treatment of other pathologies than diabetes, such as heart failure, it is important to check the age and the values of biochemical parameters such as eGFR and electrolyte levels to ensure the appropriate therapeutic efficacy and prevent side effects.