SGLT2 inhibitors reduce the absorbtion of sodium and glucose via this transporter located in the proximal tubule of the kidney. As a result, some sodium and water will be lost in the urine, resulting in a modest drop in blood pressure. Remember there is much redundancy in the kidney to reabsorb sodium and so a portion of the sodium may be reabsorbed in other parts of the nephron. In studes with
for example, systolic blood pressure fell 5 mmHg while diastolic fell 2 mmHg. Of course, these effects will vary in patients based on background therapy, the height of baseline blood pressure and other factors.
Please see this attached figure: