The antihypertensive efficacy of fimasartan was assessed based on the transition rate from a combination of calcium channel blockers (CCB) and angiotensin receptor blockers (ARB) to three-drug combination therapy, as compared to other ARBs. This nationwide cohort study used data obtained from the Korean National Health Insurance Service database. Patients who had received national health checkups within 2 years prior to January 1, 2017, and were concurrently prescribed ARBs and CCBs for > 30 days during the 6 months from January 1, 2017, to June 30, 2017 were included in the study. Patients were categorized into the 'fimasartan group' (those prescribed fimasartan) and the 'non-fimasartan group' (those prescribed ARBs other than fimasartan). The index date was set as the last day of a 30-day prescription period for ARBs and CCBs, with a subsequent 2.5-year follow-up to observe the potential addition of a third drug, such as beta-blockers or diuretics. The study included 34,422 patients with a mean age of 60.3 years and 58.3% being male. The fimasartan group constituted 2.7% (n = 928) of the total, and the non-fimasartan group, 97.3% (n = 33,494). During the follow-up period, 38 patients in the fimasartan group (14.3 per 1,000 person-years) and 3,557 patients in the non-fimasartan group (42.8 per 1,000 person-years) required additional antihypertensive medications. After multivariate adjustment for age, sex, diabetes mellitus, dyslipidemia, cancer, heart failure, systolic blood pressure, and diastolic blood pressure, the fimasartan group showed a significantly lower rate of adding a third medication (hazard ratio 2.68, 95% confidence interval 1.95-3.69) compared to that of the non-fimasartan group. Fimasartan is associated with a lower need for additional antihypertensive drugs compared to other ARBs. This implies its greater effectiveness in hypertension management, potentially enhancing cardiovascular outcomes, and minimizing polypharmacy.