9.3 : 降圧薬: 利尿薬の作用

When the glomerular filtrate passes through the renal tubule, sodium ions are reabsorbed into the blood through ion transporters that are expressed across the tubule.

This reabsorption of ions is vital for overall body function. However, excess sodium in the blood can lead to water retention, resulting in expanded blood volume and increased blood pressure.

Diuretics inhibit the renal ion transporters, preventing the reabsorption of Na⁺.

This increases urine output, facilitating the elimination of water and sodium ions from the body and reducing the overall blood volume.

The decrease in blood volume lessens the pressure exerted on the arterial walls, leading to a drop in blood pressure.

In most patients, diuretics effectively reduce systolic blood pressure by 10–15 mmHg, serving as a standalone treatment for mild to moderate hypertension.

However, they may have several side effects, including hyperuricemia, which causes elevated uric acid levels.

Accumulation of insoluble uric acid crystals in the joints leads to painful gouty attacks with swelling and redness.