Pharmacology and Clinical Applications of Diuretics

Diuretic

Agent that increases urine volume.

Natriuretic

Agent that increases renal sodium excretion.

Aquaretic

Agent that increases solute-free water excretion.

Natriuresis

Increased excretion of sodium in urine.

Thiazide Diuretics

Diuretics that decrease Na/Cl reabsorption in DCT.

Loop Diuretics

Diuretics acting on the loop of Henle.

Potassium-Sparing Diuretics

Diuretics that conserve potassium in the body.

Carbonic Anhydrase Inhibitors

Inhibit enzyme reducing NaHCO3 reabsorption.

Acetazolamide

Carbonic anhydrase inhibitor used for glaucoma.

Diuretic Action Duration

Thiazides act for 16 to 24 hours.

Low Ceiling Diuretics

Maximal effect reached at low dosages.

Renal Failure Impact

Thiazides less effective with serum creatinine >2 mg/dL.

Sequential Nephron Block

Additive effects from different tubular site actions.

Mild Diuresis

Result of decreased HCO3- and H+ formation.

Glaucoma Treatment

Acetazolamide reduces aqueous humor production.

Adverse Reactions of Acetazolamide

Includes metabolic acidosis and renal stone formation.

Thiazide Indications

Used for hypertension and heart failure.

Hypokalemia

Low potassium levels potentially causing arrhythmias.

Hyperuricemia

Elevated uric acid levels; risk for gout.

Diabetes Insipidus

Thiazides allow production of hyperosmolar urine.

Urine pH Increase

HCO3− diuresis raises urine pH within 30 minutes.

Electrolyte Imbalance

Diuretics may alter levels of K+, Ca2+, Mg2+.

Thiazide Family

Includes HCTZ, Chlorthalidone, Indapamide, Metolazone.

Clinical Use Timeline

Stable BP reduction takes 1-3 weeks.

Contraindications for Thiazides

Caution in pregnancy and renal impairment.

Hypomagnesemia

Low magnesium levels, can be prevented with potassium-retaining agents.

Bumetanide

A loop diuretic used for edema treatment.

Furosemide

Loop diuretic effective in acute pulmonary edema.

Torsemide

Loop diuretic with longer duration than others.

Diuresis

Increased urine production, often via diuretics.

Hypercalcemia

Elevated calcium levels, can be treated with diuretics.

Ototoxicity

Hearing impairment risk associated with loop diuretics.

Potassium Sparing Diuretics

Prevent potassium loss, include amiloride and spironolactone.

Aldosterone Antagonists

Block aldosterone, promote sodium excretion and potassium retention.

Spironolactone

Aldosterone antagonist causing gynecomastia in males.

Eplerenone

Selective aldosterone blocker, preferred for hypertension.

Mannitol

Osmotic diuretic used for increased intracranial pressure.

Aquaresis

Diuresis without sodium excretion, characteristic of mannitol.

Dehydration

Potential side effect of osmotic diuretics like mannitol.

SHEP Study

Demonstrated efficacy of low-dose thiazides in hypertension.

Chlorthalidone

Thiazide diuretic effective in lower doses for BP.

Gout Risk

Increased risk with diuretic use, especially thiazides.

Combination Therapy

Preferred over high-dose diuretics to avoid side effects.

Metabolic Alkalosis

Potential side effect of diuretic therapy.

Hyponatremia

Low sodium levels, possible adverse effect of diuretics.

Resistance Hypertension

Condition where BP remains high despite treatment.

Diuretic Kinetics

Oral or IV administration, variable duration of action.

Acute Hypovolemia

Severe fluid loss, a risk with diuretic use.

Potassium Monitoring

Necessary for patients on potassium-sparing diuretics.

Clinical Uses

Indications for diuretics include edema and hypertension.