Renal Meds

Question 1

Acetazolamide

Answer 1

• Carbonic anhydrase inhibitor – based on sulfa chemo drugs – low efficacy as single agent diuretic
• Act on CA in lumen and cells of proximal tubule (inhibit antiporter and leave NaHCO3 in urine) – secondary site is distal collecting duct
• Metabolic acidosis, urine pH up to 8, potassium wasting, allergies to sulfa, renal ammonia into circulation, kidney stones, bone marrow depression
• Open angle glaucoma, pre-surgical relief of glaucoma pressure, altitude sickness, counteracting diuretic induced metabolic alkalosis

Question 2

Chlorothiazide
Hydrochlorothiazide
Meetolazone

Answer 2

• Thiazide and thiazide-like also some carbonic anhydrase activity (except metolazone) – daily dosing
• Block NaCl symporter in distal convoluted tubule (maximal 5% increase in Na excretion – less effacious), no TGF, water retention during dehydration preserved
• Potassium wasting, small risk of sudden death and renal cell carcinoma, hypotension, hypokalemia, hyponatremia, metabolic alkalosis, hypercalcemia, hyperuricemia
• Hypertension (don’t risk hypovolemia), edema from CHF, calcium nephrolithiasis, osteoporosis, nephrogenic diabetes insipidus

Question 3

Bumetanide
Ethacrynic acid
Torsemide

Answer 3

• Loop diuretics
• Inhibit Na/K/2Cl symporter in ascending thick limb – no TGF
• Potassium wasting, very frequent dosing, hyponatremia, hypokalemia, volume depletion, metabolic alkalosis, hyperuricemia (bad for gout), ototoxicity
• Acute pulmonary edema, CHF, hypertension, nephrotic syndrome, edema and ascites of cirrhosis, renal failure

Question 4

Furosemide

Answer 4

• Loop diuretics – beneficial to use before diuresis begins
• Inhibit Na/K/2Cl symporter in ascending thick limb (competes for Cl site) (no TGF), also weak carbonhic anhydrase inhibitor
• Potassium wasting, very frequent dosing, hyponatremia, hypokalemia, volume depletion, metabolic alkalosis, hyperuricemia, ototoxicity, allergic
• Heart failure and pulmonary edema (increases systemic venous capacitance), hypertension, nephrotic syndrome, edema/ascites of cirrhosis, renal failure

Question 5

Amiloride (21 hr ½ life - renal excretion)

Triamterene (4 hr ½ life – metabolized)

Answer 5

• K+ sparing agent
• Inhibit renal Na channels – small increase in NaCl excretion but used to block K+ excretion – distal convoluted tubule and collecting duct
• Hyperkalemia (cardiac arrhythmia/death), megaloblastic anemia (triamterene)
• Co-administer with thiazide or loop diuretic – treat Liddle’s syndrome, aerosol to clear mucus in CF

Question 6

Eplerenone

Spironolactone

Answer 6

• K+ sparing agent – induced in response to dehydration
• Mineralcorticoid antagonists – competitively bind receptor and block function – distal convoluted tubule and collecting duct – increase Na excretion
• Hyperkalemia, diarrhea, gastritis, gastric bleeding, CNS symptoms, rash, malignancies from chronic use
• Co-administer with thiazide or loop diuretic, primary and secondary hyperaldosteronism, and treatment of choice for ascites and edema from cirrhosis

Question 7

Glycerin (oral)

Mannitol (IV)

Answer 7

• Osmotic agent – mostly given just inpatient
• Increase renal blood flow and wash out medullary salt gradient – Loop of Henle – decreased NaCl reabsorption
• Pulmonary edema, hyponatremia, dehydration, contraindicated in anuria/impaired liver function and active intracranial bleed, potassium wasting
• Acute renal failure, acute tubular necrosis, dialysis disequilibrium syndrome, acute glaucoma, mannitol to reduce brain swelling (pre and post op)

Question 8

Vasopressin

Desmopressin (synthetic analog – specific for V2)

Answer 8

• Antidiuretic
• Decrease urine volume – binds V1 (systemic) and V2 (distal tubule and collecting duct) receptors
• Coronary artery constriction and water intoxication
• Diabetes insipidus – treat central (vasopressin not produced) but not nephrogenic (problem with receptors)

Question 9

Chlorpropamide

Answer 9

• Antidiuretic
• Sulfonylurea previously used for type II diabetes
• Increases ADH secretion

Question 10

Probenecid

Answer 10

• Uricosuric agent
• First cause decreased excretion of uric acid and then inhibit urate reabsorption in lumen
• Increased risk for renal stones, interferes with renal excretion of many drugs
• Gout

Question 11

Allopurinol

Answer 11

• Miscellaneous
• Inhibits xanthine oxidase (decreases uric acid)
• Gout

Question 12

Colchicine

Answer 12

• Miscellaneous
• Reduce neutrophils
• Gout