Background: Hypertension is one of the main causes of mortality and morbidity in Indonesia. Drug usage, utilization patterns, and cost estimates are important elements in calculating drug needs in the forecasting of drug needs plans for pharmacies. Objective: to determine the pattern of drug use with the Anatomical Therapeuetik Chemical (ATC)/Defined Daily Dose (DDD) and Drug Use 90% (DU90%) methods and the estimated cost of antihypertensives with the use of antihypertensive drugs based on the national formulary. Methods: This research uses observational methods using a cross-sectional design. Retrospective data collection includes prescription from BPJS Kesehatan back-referral program (PRB) which goes into pharmacy A, B, and C for the period 2020. Results: The most widely used drugs at pharmacy A, B and C based on ATC/DDD classification were amlodipine, candesartan, ramipril, hydrochlorothiazide, and lisinopril. Amlodipine was the most frequent drug in the DU segment 90%. The highest cost of using the drug was candesartan 16 mg (Rp 4,381,531). The percentages of adherence to the use of antihypertensive drugs with the national formulary in pharmacy A, B, and C were 73.91%, 80%, and 68.42%, respectively. Conclusion: In general, the highest consumption of antihypertensive drugs in Back-Referral Program (PRB) pharmacies in the area of Kudus Regency, which is included in the DU segment 90%, was amlodipine, and the suitability of drugs with the National Formulary has not reached 100%. Referring to the results of the pattern of use of PRB drugs in this study, it is hoped that there will be better coordination between BPJS Kesehatan and pharmacies regarding the distribution and availability of PRB drugs. Keywords: ATC/DDD, DU 90%, hypertension, national formulary, PRB