How do anti-hypertensors act at the level of the kidneys? What does an anti-hypertensive that protect the kidneys mean?

The medication telmisartan acts on the renin-angiotensin-aldosterone system (RAAS) to help maintain stable blood pressure. In people with high blood pressure, this system is out of balance and we give medications from the ARB or ACE inhibitor class to block this system and reduce pressure. These medications protect the kidney by promoting better blood flow. For people with kidney failure or diabetes, we give these medications as a preventive measure to delay kidney deterioration. For people on dialysis, the machine cannot completely replace the kidneys, so medications are needed to reduce pressure and eliminate water.