The number of diagnosed hypertensive patients in Japan is estimated to be 9.93 million according to a 2017 patient survey, and the potential number of actual hypertensive patients is estimated to be 43 million. The purpose of the present study was to clarify the actual condition of the Do-shoho (refill of the previous prescription) period for antihypertensive drugs prescribed for a long duration, and to obtain basic data for considering the introduction of a refill system in Japan. Data were collected from the patient medication profile of patients who were prescribed amlodipine OD tablets (Chemiphar®) from July 2012 to December 2019, and the Mann-Whitney U test or Kruskal-Wallis test were performed with the Do-shoho period as the test variable. A generalized linear model was used to analyze the items for which significant differences were obtained. The results of the analysis showed that the factors affecting the duration of the Do-shoho were the prescribing source, diagnosis, and the maximum number of prescription days. Of the patients surveyed (N=321), 199 (62.0%) had a Do-shoho duration of 6 months or longer, which was more than half of the total number of patients. The results suggest that many patients may be eligible for the refill prescription system if pharmacists are able to properly assess the continuation of prescriptions.