Schlafer Renal Pharmacology

a

261. Diuretic-induced hypokalemia can have clinically significant consequences, and so it's important to know which diuretics are potassium- wasting and which spare (reduce net renal excretion of) potassium, because potassium-sparing diuretics play an important role in preventing hypokalemia or treating asymptomatic deficiencies of this cation. Which of the following is classified as potassium-sparing? a. Amiloride b. Bumetanide c. Hydrochlorothiazide d. Metolazone e. Torsemide

d

262. We have a patient with heart failure, unacceptably low cardiac output, and intense reflex-mediated sympathetic activation of the peripheral vasculature that is attempting to keep vital organ perfusion pressure sufficiently high. The patient is edematous, and has ascites, because of the poor cardiac function and renal compensations for it. Which one of the following drugs should be avoided in this patient because it is most likely to compromise function of the already failing heart and the circulatory system overall? a. Amiloride b. Ethacrynic acid c. Hydrochlorothiazide d. Mannitol e. Spironolactone

d

263. One of your clinic patients is being treated with spironolactone. Which of the following statements best describes a property of this drug? a. Contraindicated in heart failure, especially if severe b. Inhibits Na+ reabsorption in the proximal renal tubule of the nephron c. Interferes with aldosterone synthesis d. Is a rational choice for a patient with an adrenal cortical tumor e. Is more efficacious than hydrochlorothiazide in all patients who receive the drug

c

264. A patient taking an oral diuretic for about 6 months presents with elevated fasting and postprandial blood glucose levels. You check the patient's HbA1c and find it is elevated compared with normal baseline values obtained 6 months ago. You suspect the glycemic problems are diuretic-induced. Which of the following was the most likely cause? a. Acetazolamide b. Amiloride c. Chlorothiazide d. Spironolactone e. Triamterene

c

265. Chlorthalidone and torsemide are members of different diuretic classes, in terms of mechanisms of action, but they share the ability to cause hypokalemia. Which of the following statements best describes the general mechanism by which these drugs cause their effects that lead to net renal loss of potassium? a. Act as aldosterone receptor agonists, thereby favoring K+ loss b. Block proximal tubular ATP-dependent secretory pumps for K+ c. Increase delivery of Na+ to principal cells in the distal nephron, where tubular Na+ is transported into the cells via a sodium channel in exchange for K+, which gets eliminated in the urine d. Inhibit a proximal tubular Na,K-ATPase such that K+ is actively pumped into the urine e. Lower distal tubular urine osmolality, thereby favoring passive diffusion of K+ into the urine

b

266. A patient was in a recumbent position for a 45-minute dental procedure. When the procedure was completed she stood up quickly and promptly got light-headed and fainted. The cause was hypotension due to hypovolemia from excessive diuresis, attributed to a drug prescribed by her physician and taken for several months. Which of the following was the most likely cause? a. Acetazolamide b. Furosemide c. Hydrochlorothiazide d. Spironolactone e. Triamterene

d

267. A 52-year-old man presents to your clinic for his first visit with you, after moving from a distant town. His only medications are a statin, aspirin (81 mg/day) and metolazone. The pharmacist who filled his prescriptions told the gentleman why he was taking the aspirin and the statin, but unfortunately referred to the metolazone as a "water pill." Thus, you're asked about it. Assuming proper prescribing, which of the following is the most likely reason why the metolazone was prescribed? a. Adjunctive management of an adrenal cortical tumor b. Adjunctive management of hepatic cirrhosis from years of excessive alcohol consumption c. Hypertension accompanied by a history of gout and diabetes d. Treatment of essential hypertension e. Treatment of edema and ascites from heart failure

a

268. Urinary potassium concentrations are measured before and after several weeks of administering a loop diuretic (typical daily dosages). We find that posttreatment urine K+ concentrations are substantially lower than those measured at baseline. Which of the following is the most likely explanation for this observation? a. An expected response to the drug b. Loop diuretics cause potassium-wasting only in in vitro experimental models c. Measurements of posttreatment urine K+ concentrations were erroneous d. The patient has hypoaldosteronism from bilateral adrenalectomy e. The patient has significantly impaired renal function

a

269. A patient has very high serum uric acid levels, has had two acute gout attacks, and is at imminent risk of developing acute uric acid nephropathy. We will treat the patient with proper anti-inflammatory drugs and other agents, but feel that reducing solubility of uric acid in the urine, by raising urine pH, might help stave-off the development of renal problems. Which of the following drugs produce this desired renal effect without appreciably increasing systemic risks of the hyperuricemia? a. Acetazolamide b. Antidiuretic hormone (ADH) (vasopressin [VP]) c. Ethacrynic acid d. Furosemide e. Hydrochlorothiazide

a

270. A 58-year-old man with a history of hypertension and hypercholesterolemia is diagnosed with heart failure. We start therapy with a loop diuretic. Which of the following would you expect to occur along with the increased urine volume caused by the diuretic? a. Dilute (hypotonic) urine because normal urine concentrating mechanisms are impaired b. Hypercalcemia due to impaired renal Ca2+ excretion c. Reduced net excretion of Cl- d. Metabolic acidosis due to increased renal bicarbonate excretion e. Reduced serum uric acid (urate) concentrations because of increased urate excretion

c

271. A patient with mild heart failure and edema fails to respond adequately to maximum recommended dosages of chlorthalidone. Which of the following is the most likely appropriate and most fruitful next step in terms of restoring the diuretic response? a. Add hydrochlorothiazide b. Add metolazone c. Replace chlorthalidone with furosemide d. Replace chlorthalidone with hydrochlorothiazide e. Try increasing the chlorthalidone dose anyway

b

272. A hypertensive patient has been on long-term therapy with lisinopril for hypertension. The drug isn't controlling pressure as well as wanted, so the physician decides to add triamterene as the (only) second drug. Which of the following is the most likely outcome of adding this diuretic to the ACE inhibitor regimen? a. Blood pressure would rise abruptly b. Better BP control, but with a risk of hyperkalemia c. Cardiac depression, because both drugs directly depress the heart d. Cough that may be severe, even though there was no cough with lisinopril alone e. Hypernatremia, because ACE inhibitors counteract triamterene's natriuretic effect

b

273. Package inserts for a drug caution against administering the medication concurrent with any other drug that can raise or lower serum sodium concentrations. The risks are inadequate or excessive effects of the drug, depending on the direction in which serum sodium concentrations change. This, of course, requires cautious use or avoidance (if possible) of the common diuretics. To which of the following drugs does this caution or warning most likely apply? a. Cholestyramine b. Lithium c. Nifedipine d. Phenylephrine e. Statin-type cholesterol-lowering drugs

a

274. Your patient, who lives in Death Valley, California (altitude 240 feet below sea level), is planning a vacation that includes a short hike to the top of Mount Everest (altitude approx. 29,000 feet above sea level). You're concerned about "altitude sickness." He has no other significant medical conditions, and takes no other drugs that would interact with the drug you will prescribe for his trip. Which of the following drugs would you recommend that this adventurer start taking before his trek, and continue until he returns to an altitude much closer to sea level? a. Acetazolamide b. Amiloride c. Bumetanide d. Furosemide e. Spironolactone f. Triamterene

c

275. A patient with heart failure has been managed with digoxin and furosemide and is doing well by all measures, for 3 years. He develops acute rheumatoid arthritis and is placed on rather large doses of a very efficacious nonsteroidal anti-inflammatory drug —one that inhibits both cyclooxygenase pathways (COX-1 and -2). Which of the following is the most likely outcome of adding the NSAID? a. Hyperchloremic acidosis indicative of acute diuretic toxicity b. Dramatic increase of furosemide's potassium-sparing effects c. Edema, weight gain, and other signs/symptoms indicative of reduced diuresis d. Increased digoxin excretion e. Reduced digoxin effects because the NSAID competes with digoxin for myocyte receptor-binding sites

a

276. A patient presents with chronic open angle glaucoma. Which of the following "renal" drugs might be prescribed as an adjunct to lower intraocular pressure and help manage his condition? a. Acetazolamide b. Amiloride c. Furosemide d. Spironolactone e. Triamterene

a

277. Furosemide's main mechanism of action involves inhibition of a Na+,K+, 2Cl− cotransporter. In which part of the nephron is this cotransporter located? a. Ascending limb, loop of Henle b. Collecting duct c. Descending limb, loop of Henle d. Distal convoluted tubule e. Proximal tubule

b

278. A patient with severe infectious disease is being treated with an aminoglycoside antibiotic. Which of the following diuretics should be avoided, if possible, for this patient, because of the risk of a serious common and additive adverse effect? a. Acetazolamide b. Furosemide c. Metolazone d. Spironolactone e. Triamterene

e

279. We have a patient with a recently diagnosed adrenal cortical adenoma. Among the pertinent cushingoid signs and symptoms are hypertension and weight gain from fluid retention, and hypernatremia and hypokalemia. Which of the following drugs would be the most rational to prescribe, alone or adjunctively, to specifically antagonize both the renal and the systemic effects of the hormone excess? a. Acetazolamide b. Amiloride c. Furosemide d. Metolazone e. Spironolactone

b

280. A patient has been referred to your academic medical center because of recent-onset ventricular ectopy, second degree AV nodal block, chromatopsia, and other extracardiac signs and symptoms of digoxin intoxication. His family doctor, who has been treating him for a host of common medical problems over the last 30 years, had prescribed furosemide and digoxin for this gentleman's heart failure. Blood tests show that serum digoxin levels are well within a normal range. We believe the problems are diuretic-induced. Which of the following does the diuretic most likely do to account for the digoxin toxicity? a. Caused hypercalcemia b. Caused hypokalemia c. Caused hyponatremia d. Displaced digoxin from tissue binding sites e. Inhibited digoxin's metabolic elimination

a

281. A 48-year-old man develops acute heart failure as one consequence of septicemia. His medical history is well documented. Among other things, it reveals poorly controlled Type I diabetes mellitus, and a near-fatal allergic response, 10 years ago, to a sulfonamide antibiotic. The patient has now developed significant edema and ascites, among other important clinical findings, due to sepsis. We will administer appropriate antibiotics and cardiac inotropes, but also need to administer a diuretic to promptly reduce circulating fluid volume and hemodynamically "unload" the failing heart. Which of the following diuretics would be most appropriate in terms of managing the hemodynamic problems and posing the lowest risk of altering blood glucose levels or eliciting a sulfonamide-related allergic reaction? a. Ethacrynic acid b. Furosemide c. Hydrochlorothiazide d. Mannitol e. Metolazone

b

282. Amiloride is a useful drug for managing hypokalemia caused by other drugs. Which of the following statements best describes the mechanism by which amiloride causes its potassium-sparing effects? a. Blocks the agonist effects of aldosterone with its renal tubular receptors b. Blocks distal tubular sodium channels and, ultimately, Na+-K+ exchange c. Hastens metabolic inactivation of aldosterone d. Stimulates a proximal tubular Na,K-ATPase e. Suppresses cortisol and aldosterone synthesis and release in the adrenal cortex

c

283. A patient with severe heart failure is in the ICU. His urine output is dangerously low. We begin an intravenous infusion of dopamine at a usual therapeutic dose and urine output rises quickly and dramatically. Which of the following is the most likely mechanism by which the dopamine causes this effect? a. Blocked β-adrenergic receptors in the juxtaglomerular apparatus, thereby inhibiting renin release and susequent angiotensin-mediated aldosterone release from the adrenal cortex. b. Directly inhibited a renal Na+-K+-2Cl− cotransporter in the loop of Henle. c. Improved renal blood flow and glomerular filtration d. Lowered the medullary-to-cortical osmotic gradient, such that normal urine concentrating mechanisms were impaired e. Reduced the permeability of the ascendng limb, loop of Henle, and of the collecting ducts, to water

d

284. A patient has had recurrent episodes of symptomatic hyponatremia, and is at great risk of recurrences. He now requires administration of a diuretic. Which of the following diuretics is most likely to precipitate another recurrence of the hyponatremia, and so should be avoided for that reason? a. Bumetanide b. Ethacrynic acid c. Furosemide d. Hydrochlorothiazide e. Torsemide

c

285. We have a patient with essential hypertension. He is being treated with hydrochlorothiazide and a calcium channel blocker, and is doing well. He also takes atorvastatin for hypercholesterolemia, and aspirin for prophylaxis of MI due to thrombosis. He is now diagnosed with a seizure disorder. We begin therapy with one of the suitable anticonvulsants that, fortunately, does not alter the metabolism of any of the medications prescribed for his cardiovascular problems. We've also read that systemic administration of acetazolamide may prove to be a useful adjunct to the anticonvulsant therapy: the metabolic acidosis it causes may help suppress seizure development or spread. So, we start acetazolamide therapy too. Which of the following is the most likely outcome of adding the acetazolamide? a. Excessive rises of serum sodium concentrations b. Hypertensive crisis (antagonism of both antihypertensive drugs) c. Hypokalemia via synergistic actions with the thiazide d. Spontaneous bleeding (potentiation of aspirin's actions) e. Sudden circulating volume expansion, onset of heart failure

d

286. The table shows the urinary electrolyte excretion patterns typical of various prototype diuretics. These are qualitative changes, and do not reflect the magnitude of the changes. They show whether excretion of an electrolyte (net amount) is increased or decreased; they do not reflect changes in urine concentrations of these substances. Which of the following drugs causes effects most similar, if not identical, to unknown Drug 2? a. Acetazolamide b. Amiloride c. Chlorthalidone d. Furosemide e. Hydrochlorothiazide