The most commonly used antihypertensives in Indonesia vary according to the age of the patient. At the age of 40-60 years, angiotensin-converting enzyme inhibitor (ACEi) and calcium channel blockers (CCBs) are usually given to older patients. All age groups were treated with a combination of CCB and angiotensin receptor blocker (ARB). Captopril is one of the ACE inhibitor classes, and captopril can lower blood pressure, improve renal impairment, and suppress kidney inflammation through the inactivation of NF-κB in hypertensive mice. Hypertension is closely related to renal dysfunction, requiring blood pressure to be lowered to the normotensive range to prevent progressive kidney damage. In the acute reperfusion stage, captopril prevents excessive angiotensin II synthesis, improves renal dysfunction, inhibited intrarenal inflammation, and better histopathologic findings. Most of the renoprotective effects of captopril occur in the acute reperfusion stage. At the same time, captopril significantly reduces NO availability, exacerbates intrarenal hypoxia, and exacerbates oxidative stress. This study aims to determine the effect of captopril on systolic blood pressure and diastolic blood pressure. In this study, all experimental animals were made hypertensive first by inducing 8% NaCl for 21 days given orally. Then the group with renal complications was induced by administering gentamicin for seven days provided intraperitoneally. Blood creatinine levels were measured using a Photometer5010V5 +. Measurement of systolic blood pressure and diastolic blood pressure using the Non-Invasive Blood Pressure (NIBP) instrument. The data from this study were analyzed using two-way ANOVA. The results showed that complications of renal dysfunction in hypertensive rats had a significant effect on reducing systolic blood pressure and diastolic blood pressure (p ˂ 0.05). The administration of captopril at doses of 1.25 mg, 2.5 mg, and 5 mg significantly affected decreased systolic blood pressure and diastolic blood pressure (p ˂ 0.05). Captopril 5 mg dose was the most effective in lowering systolic blood pressure and diastolic blood pressure.