BP, The Kidneys and Diuretics as Antihypertensive Agents

(A Rapid Socratic Review)

BP, Kidneys and Diuretics as Anit-HTN Agents According to JNC 7 guidelines (off-line), please define the following: Normal blood pressure <120/80 mm Hg Prehypertension 120 to 139/80 to 89 mm Hg Stage I hypertension 140 to 159/90 to 99 mm Hg Stage II hypertension â&#x2030;Ľ 160/100 mm Hg Goal blood pressure (BP) in patients without diabetes mellitus (DM) or chronic kidney disease? <140/90 mm Hg Goal BP in patients with DM or chronic kidney disease? <130/80 mm Hg Marc Imhotep Cray, M.D.

Online: Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment.pdf

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BP, Kidneys and Diuretics as Anit-HTN Agents (2) 1. Define essential hypertension (HTN) 2. True or False? The majority of HTN cases are essential.

3. What is the BP equation?

4. What is responsible for moment-to-moment changes in BP? 5. Where are the baroreceptors that are sensitive to the moment-to-moment changes in BP located?

6. What organ is responsible for the long- term control of BP? Marc Imhotep Cray, M.D.

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Answers 1. HTN of unknown etiology, that is, primary hypertension 2. True 3. Blood pressure (BP) = cardiac output (CO) Ă&#x2014; total peripheral resistance (TPR) 4. Baroreceptor reflexes (autonomic nervous system) 5. Aortic arch; carotid sinuses 6. Kidney

Marc Imhotep Cray, M.D.

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BP, Kidneys and Diuretics as Anit-HTN Agents (3) 7. The kidney responds to reduced BP by releasing what peptidase?

8. Renin is responsible for what enzymatic reaction?

9. What enzyme is responsible for converting AT-I to AT-II? 10. Where is ACE found?

11. What function does AT-II have with regard to BP regulation?

12. Where is aldosterone synthesized?

13. What function does aldosterone have with regard to BP regulation?

Marc Imhotep Cray, M.D.

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Answers 7. Renin 8. Conversion of angiotensinogen to angiotensin-I (AT -I) 9. Angiotensin-converting enzyme (ACE) in the lungs 10. Vasoconstriction (increases TPR thereby increases BP); stimulation of aldosterone release 11. Zona glomerulosa of the adrenal cortex 12. Increases reabsorption of sodium ion in exchange for potassium ion; water osmotically follows sodium ion, therefore, aldosterone leads to salt and water 13. retention thereby increasing BP

Marc Imhotep Cray, M.D.

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BP, Kidneys and Diuretics as Anit-HTN Agents (4) 14. What is the name of the most common thiazide diuretic used in the treatment of HTN? 15. What are the immediate/acute effects of thiazide diuretics?

16. What are the chronic effects of thiazide diuretics?

17. What is the site of action of thiazide diuretics?

18. What transporter (in the distal convoluted tubule) is inhibited by thiazide diuretics?

19. Give examples of thiazide diuretics: Marc Imhotep Cray, M.D.

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Answers 14. Hydrochlorothiazide (HCTZ) 15. Increased sodium, chloride, and water excretion which leads to decreased blood volume 16. Decreased TPR 17. Distal convoluted tubule of nephron 18. Na+/Cr transporter 19. HCTZ; chlorothiazide; chlorthalidone

Marc Imhotep Cray, M.D.

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BP, Kidneys and Diuretics as Anit-HTN Agents (5) 20.Thiazide diuretics may be ineffective in patients with creatinine clearances of less than what?

21.With regard to blood concentrations, state whether each of the following electrolytes will be increased or decreased in patients on thiazide diuretic therapy: Calcium, Magnesium, Potassium, Sodium 22.With regard to increased renal calcium reabsorption, what are thiazide diuretics sometimes used for?

23.What are the adverse effects of HCTZ? Marc Imhotep Cray, M.D.

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Answers 20. 50 mL/min 21. Increased, Decreased, Decreased, Decreased 22. Treatment of calcium stones in the urine 23. Hypercalcemia; hypokalemia; hypomagnesemia; hyperglycemia; hyperuricemia; pancreatitis; metabolic alkalosis; Stevens Johnson syndrome; hyperlipidemia

Marc Imhotep Cray, M.D.

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BP, Kidneys and Diuretics as Anit-HTN Agents (6) 24.Patients allergic to what class of antimicrobials may also be sensitive to thiazide diuretics?

25.What is the site of action of loop diuretics?

26.Give examples of loop diuretics:

27.Which loop diuretic can be given safely to patients with allergy to sulfonamide antimicrobials?

28.What transporter (in the thick ascending loop of Henle) is inhibited by loop diuretics?

Marc Imhotep Cray, M.D.

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Answers 24. Sulfonamides 25. Loop of Henle (thick ascending limb) 26. Furosemide; bumetanide; ethacrynic acid; torsemide 27. Ethacrynic acid 28. Na+/KV2Cl~ transporter

Marc Imhotep Cray, M.D.

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BP, Kidneys and Diuretics as Anit-HTN Agents (7) 29.True or False? Loop diuretics increase calcium excretion.

30.What are the adverse effects of loop diuretics?

31.Which loop diuretic is the most ototoxic?

32.Which renal tubular segment is responsible for the majority of sodium reabsorption?

33.What is the mechanism of action of mannitol?

34.What is mannitol used for?

Marc Imhotep Cray, M.D.

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Answers 29. True 30. Hypersensitivity; hypocalcemia; hypokalemia; hypomagnesemia; metabolic alkalosis; hyperuricemia; ototoxicity 31. Ethacrynic acid 32. Proximal convoluted tubule (>60%) 33. Acts as an osmotic diuretic, thereby drawing water via increased osmolality, into the proximal convoluted tubule, loop of Henle (thin descending limb), and the collecting ducts 34. Decreases intraocular and intracranial pressure; prevents anuria in hemolysis and rhabdomyolysis Marc Imhotep Cray, M.D.

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BP, Kidneys and Diuretics as Anit-HTN Agents (8) 35.Give two examples of carbonic anhydrase inhibitors (CAIs): 36.What is the mechanism of action of CAIs? 37.What metabolic disturbance may be caused by CAIs? 38.What are CAIs used for?

39.Name three potassium-sparing diuretics:

40.What is the mechanism of action of spironolactone?

Marc Imhotep Cray, M.D.

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Answers 35. Acetazolamide, Dorzolamide 36. Increased excretion of sodium and bicarbonate 37. Metabolic acidosis 38. Altitude sickness (decreases cerebral and pulmonary edema); glaucoma (decreases aqueous humor formation thereby decreasing intraocular pressure); metabolic alkalosis; to enhance renal excretion of acidic drugs 39. Spironolactone, Triamterene , Amiloride 40. Aldosterone receptor antagonist

Marc Imhotep Cray, M.D.

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BP, Kidneys and Diuretics as Anit-HTN Agents (9) 41.Where in the kidney is the aldosterone receptor found?

42.Where in the kidney does triamterene and amiloride work?

43.What are the adverse effects of spironolactone?

44.Triamterene is often used in combination with what other diuretic?

45.Spironolactone is used to treat what conditions?

46.Amiloride is used to treat what conditions?

Marc Imhotep Cray, M.D.

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Answers 41. Basolateral membrane of the principal cell in the collecting duct 42. Sodium ion channel on the luminal side of the principal cell in the collecting duct 43. Hyperkalemia; metabolic acidosis; gynecomastia 44. HCTZ 45. HTN; CHF; ascites 46. HTN; CHF; lithium-induced diabetes insipidus

Marc Imhotep Cray, M.D.

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