Diuretic Therapy

Diuretic selection begins with the problem being treated, not with the drug name. A patient with pulmonary congestion or marked peripheral edema needs effective sodium removal; a patient with uncomplicated hypertension usually needs sustained reduction in vascular resistance and blood pressure. Loop diuretics are the stronger natriuretics, whereas thiazide and thiazide-like agents act farther downstream and are especially useful for chronic blood-pressure control. The clinical response is never judged by urine volume alone. Check whether congestion, blood pressure, weight, renal function, and electrolytes are moving in the intended direction. A falling urine output with rising creatinine may mean inadequate renal perfusion rather than treatment success, while confusion in an older adult taking a thiazide may signal clinically important hyponatremia. Kidney function changes drug handling and efficacy, but an eGFR below 30 mL/min/1.73 m² is not an automatic reason to dismiss every thiazide-like option. For Canadian primary care, standardized blood pressure at or above 130/80 mm Hg meets the 2025 guideline definition of hypertension. Thiazide or thiazide-like diuretics remain one of three first-line classes, and initial low-dose combination therapy is generally...