Pharmacology: Pharmacokinetics, Pharmacodynamics, and Renal Drug Handling (Diuretics & Kidney Function)

Vocabulary-style flashcards covering pharmacokinetics, pharmacodynamics, drug interactions, and renal drug handling (diuretics and kidney function).

Prodrug

A drug given in an inactive form that the body metabolizes into the active drug (often in the liver).

Active drug

The pharmacologically active form that produces the drug’s effects, whether given directly or formed from a prodrug.

Enzyme inhibition

Decreases the metabolism of a drug, increasing its active levels and potentially causing toxicity.

Enzyme induction

Increases the metabolism of a drug, lowering its plasma concentration and potentially reducing efficacy.

Pharmacokinetics

The study of how a drug moves through the body: absorption, distribution, metabolism, and excretion.

Pharmacodynamics

The study of how a drug affects the body and how drugs interact at their sites of action, inducing a change in paitent’s response without altering.

Pharmacokinetic drug interaction

A drug interaction that changes drug levels by altering absorption, distribution, metabolism, or excretion.

Pharmacodynamic drug interaction

A drug interaction where the effects of one drug change the effect of another without changing drug levels.

Antagonistic pharmacodynamic interaction

One drug reduces the effect of another, offsetting its action.

Additive pharmacodynamic interaction

Combined effect equals the sum of the individual effects.

Synergistic pharmacodynamic interaction

Combined effect exceeds the sum of the individual effects.

Onset of action

Time from drug administration to the beginning of its effect.

Duration of action

Time during which the drug remains in the therapeutic range (above MEC until below MEC).

Therapeutic range

Plasma concentration window where a drug is effective and not toxic (between MEC and toxic level).

Enteric coating

A coating that protects a drug from stomach acid and dissolves in the intestines.

Intranasal administration

Delivery of a drug through the nasal passages for topical or systemic effects.

Glomerulus

Capillary network in the kidney where filtration of blood into the tubules begins.

Afferent arteriole

The small vessel that brings blood into the glomerulus.

Efferent arteriole

The vessel that carries blood away from the glomerulus; constriction increases filtration pressure.

Nephron

The functional unit of the kidney where filtration, reabsorption, and secretion occur.

Proximal tubule

Renal tubule segment where about 60–70% of reabsorption (water, Na, glucose) occurs.

Loop of Henle

Renal tubule with descending and ascending limbs; major site of Na and water reabsorption with variable water permeability.

Distal tubule

Renal tubule segment where final adjustments of sodium and water reabsorption occur; regulated by aldosterone.

Collecting duct

Final site for urine concentration; regulated by ADH and aldosterone.

Glomerular filtration rate (GFR)

Rate at which plasma is filtered through the glomerulus; key measure of kidney function.

Creatinine

Waste product from muscle; filtered by kidneys and used to estimate GFR/creatinine clearance.

Creatinine clearance

Estimated rate kidneys remove creatinine from blood; proxy for GFR (often via formulas).

CKD-EPI

A modern equation to estimate GFR using serum creatinine (and cystatin C), more accurate across body types than creatinine clearance.

Albumin

A major plasma protein that helps maintain intravascular volume via oncotic pressure.

Oncotic pressure

Osmotic pressure exerted by plasma proteins (mainly albumin) that pulls water into vessels.

Third spacing

Fluid shifts from intravascular space into interstitial spaces or body cavities, reducing circulating volume.

Ascites

Fluid accumulation in the peritoneal (abdominal) cavity, often from liver disease; can impair breathing.

Pulmonary edema

Fluid accumulation in the lungs that impairs gas exchange; seen as white areas on imaging.

Edema

Excess fluid in interstitial spaces; can be peripheral (limbs) or in body cavities (ascites, pulmonary).

Osmotic diuretics

Diuretics (eg, mannitol, glycerin) that stay in the tubule lumen, drawing water into urine; used for cerebral edema and other situations.

Mannitol

An osmotic diuretic used to reduce intracranial pressure and certain edemas by osmotic action.

Glycerin

An osmotic agent used similarly to mannitol for specific indications (less common).

Acetazolamide

Carbonic anhydrase inhibitor used to decrease aqueous humor production in glaucoma and for certain overdoses; not a first-line diuretic.

Loop diuretics

Strong diuretics that inhibit the Na-K-2Cl cotransporter in the thick ascending limb; high ceiling and effective even with renal disease.

Furosemide (Lasix)

A commonly used loop diuretic for edema and volume overload; potent and versatile (oral/IV).

Bumetanide

A loop diuretic with strong diuretic effect, used similarly to furosemide.

Torsemide

A loop diuretic used for diuresis in edema and heart failure; oral and IV forms available.

Thiazide diuretics

Block NaCl reabsorption in the distal tubule; weaker, lower ceiling, useful for mild edema and hypertension.

Hydrochlorothiazide

A widely used thiazide diuretic that reduces Na reabsorption in the distal tubule.

Chlorthalidone

A long-acting thiazide-like diuretic; effective for hypertension and edema.

Metolazone

A potent thiazide-like diuretic often used for refractory edema; works even when kidney function is reduced.

Indapamide

A thiazide-like diuretic used for hypertension and edema; varying potency and duration.

Potassium-sparing diuretics

Diuretics that limit potassium loss in the distal nephron, risking hyperkalemia.

Amiloride

Blocks epithelial Na+ channels in the distal tubule; preserves potassium while providing diuretic effect.

Triamterene

Blocks epithelial Na+ channels in the distal tubule; used with thiazides to balance potassium effects.

Aldosterone antagonists

Block aldosterone receptors, increasing diuresis and causing potassium retention; include spironolactone and eplerenone.

Spironolactone

Aldosterone receptor antagonist with hormonal side effects; used in heart failure, liver disease, and certain acne cases.

Eplerenone

Aldosterone receptor antagonist with fewer hormonal side effects than spironolactone; used in heart failure and hypertension.

Hypokalemia

Low serum potassium; common with loop and thiazide diuretics; can cause cramps and arrhythmias.

Hyperkalemia

High serum potassium; risk with potassium-sparing diuretics and aldosterone antagonists; can cause dangerous arrhythmias.

Orthostatic hypotension

Drop in blood pressure on standing due to decreased intravascular volume; a risk during diuresis.

Hypovolemia

Low intravascular volume; can occur with aggressive diuresis; risks include reduced organ perfusion.

Renal elimination

Removal of drugs from the body via the kidneys (urine).

Creatinine production

Creatinine is produced at a relatively constant rate from muscle mass and is used to gauge kidney function.

Daily weights

Regular weighing to monitor fluid balance and diuretic response in hospitalized patients.

Acute kidney function monitoring

Tracking BP, electrolytes, BUN/creatinine, and urine output to ensure safe diuresis and perfusion.