Question
Thiazide diuretics.
Answer
Thiazide diuretics act at the distal convoluted tubule.
MOA: thiazide (e.g. hydrochlorothiazide) → inhibits the Na⁺-Cl⁻ cotransporter in the distal convoluted tubule → moderate natriuresis (weaker than loop diuretics, since most Na⁺ reabsorption already occurred upstream); also promotes Ca²⁺ reabsorption at this site (the opposite of loop diuretics), useful in idiopathic hypercalciuria.
Uses: hypertension (first-line, especially in the elderly), mild edema states, nephrogenic diabetes insipidus (paradoxical antidiuretic effect via volume depletion/enhanced proximal reabsorption), idiopathic hypercalciuria/renal calculi prevention.
Adverse effects: hypokalemia, hyponatremia, hyperglycemia, hyperuricemia, hyperlipidemia, hypercalcemia (contrasted with loop diuretics’ hypocalcemia).