Final answer:
Thiazide and loop diuretics can cause an increase in blood pH by inhibiting the reabsorption of sodium and chloride ions, leading to increased bicarbonate concentration which buffers excess hydrogen ions.
Step-by-step explanation:
The diuretics known for increasing blood pH (alkalemia) include thiazide diuretics and loop diuretics, like hydrochlorothiazide and furosemide respectively. These diuretics inhibit the reabsorption of sodium and chloride ions, which can lead to a relative increase in the bicarbonate concentration or a decrease in the levels of excess hydrogen ions in the blood. As a result, the blood becomes more alkaline. Bicarbonate is a major blood buffer, and increased bicarbonate concentration can therefore buffer more H+ ions, raising blood pH. This happens because when the kidneys excrete more sodium, the body compensates by reabsorbing more bicarbonate, which is the base component of the body's primary buffer system.
In medicine, such diuretics can be prescribed to correct metabolic alkalosis in addition to their use in hypertension and congestive heart failure.