1 / 22

Chapter 44

Chapter 44. Drugs Acting on the Renin-Angiotensin-Aldosterone System. Drugs Acting on the Renin-Angiotensin-Aldosterone System. Physiology of the renin-angiotensin-aldosterone system Angiotensin-converting enzyme inhibitors Angiotensin II receptor blockers Aldosterone antagonists.

skah
Télécharger la présentation

Chapter 44

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 44 Drugs Acting on the Renin-Angiotensin-Aldosterone System

  2. Drugs Acting on the Renin-Angiotensin-Aldosterone System • Physiology of the renin-angiotensin-aldosterone system • Angiotensin-converting enzyme inhibitors • Angiotensin II receptor blockers • Aldosterone antagonists

  3. Physiology of the Renin-Angiotensin-Aldosterone System • Type of angiotensin • Angiotensin I • Angiotensin II • Angiotensin III • Actions of angiotensin II • Vasoconstriction • Release of aldosterone • Alteration of cardiac and vascular structure

  4. Physiology of the Renin-Angiotensin-Aldosterone System • Actions of aldosterone • Regulation of blood volume and blood pressure • Pathologic cardiovascular effects

  5. Fig. 44–1. Regulation of blood pressure by the renin-angiotensin-aldosterone system.

  6. Physiology of the Renin-Angiotensin-Aldosterone System • Formation of angiotensin II by renin and angiotensin-converting enzyme (ACE) • Renin • Catalyzes the formation of angiotensin I from angiotensinogen • Regulation of renin release • Angiotensin-converting enzyme (kinase II) • Catalyzes the conversion of angiotensin I (inactive) to angiotensin II (highly active)

  7. Physiology of the Renin-Angiotensin-Aldosterone System • Regulation of blood pressure by the renin-angiotensin-aldosterone system • Helps regulate blood pressure in the presence of hemorrhage, dehydration, or sodium depletion • Acts in two ways • Constricts renal blood vessels • Acts on the kidney to promote retention of sodium and water and excretion of potassium • Tissue (local) angiotensin II production

  8. Angiotensin-Converting Enzyme Inhibitors • Mechanism of action and overview of pharmacologic effects • Reducing levels of angiotensin II • Increasing levels of bradykinin • Pharmacokinetics

  9. Angiotensin-Converting Enzyme Inhibitors • Therapeutic uses • Hypertension • Heart failure • Myocardial infarction (MI) • Diabetic and nondiabetic nephropathy • Prevention of MI, stroke, and death in patients at high cardiovascular risk MI = myocardial infarction.

  10. Fig. 44–2. Overview of ACE inhibitor actions and pharmacologic effects.

  11. Angiotensin-Converting Enzyme Inhibitors • Adverse effects • First-dose hypotension • Fetal injury • Cough • Angioedema • Hyperkalemia • Dysgeusia and rash • Renal failure • Neutropenia

  12. Angiotensin-Converting Enzyme Inhibitors • Drug interactions • Diuretics • Antihypertensive agents • Drugs that raise potassium levels • Lithium • Nonsteroidal anti-inflammatory drugs

  13. Angiotensin-Converting Enzyme Inhibitors • Preparations, dosage, and administration • Except for enalaprilat, all ACE inhibitors are administered orally • All available in single-drug formulations • Except for captopril and moexipril, all oral formulations may be administered without regard to meals

  14. Angiotensin II Receptor Blockers • Mechanism of action and overview of pharmacologic effects • Block access of angiotensin II • Cause dilation of arterioles and veins • Prevent angiotensin II from inducing pathologic changes in cardiac structure • Reduce excretion of potassium • Decrease release of aldosterone • Increase renal excretion of sodium and water • Do not inhibit kinase II • Do not increase levels of bradykinin

  15. Fig. 44–3. Elevation of glomerular filtration pressure by angiotensin II.

  16. Angiotensin II Receptor Blockers • Therapeutic uses • Hypertension, heart failure, myocardial infarction • Diabetic nephropathy • If unable to tolerate ACE inhibitors: protection against MI, stroke, and death from cardiovascular (CV) causes in high-risk patients • Migraine headache • May prevent development of diabetic retinopathy • New data show that ACE inhibitors and angiotensin II receptor blockers (ARBs) are not effective for primary prevention of nephropathy in normotensive diabetic patients

  17. Angiotensin II Receptor Blockers • Adverse effects • Angioedema • Fetal harm • Renal failure • Possibility of promoting cancer

  18. Direct Renin Inhibitors • Aliskiren (Tekturna) • Binds tightly with renin and inhibits the cleavage of angiotensinogen to angiotensin I • Side effects • Angioedema, cough, GI effects, hyperkalemia, fetal injury, and death

  19. Aldosterone Antagonists • Eplerenone (Inspra) • Mechanism of action • Selective blockade of aldosterone receptors • Therapeutic uses • Hypertension • Heart failure • Pharmacokinetics • Absorption is not affected by food • Adverse effects • Hyperkalemia

  20. Aldosterone Antagonists • Eplerenone (Inspra) (cont’d) • Drug interactions • Inhibitors of CYP3A4 • Drugs that raise potassium levels • Use with caution when combined with lithium

  21. Aldosterone Antagonists • Spironolactone (Aldactone) • Mechanism of action • Blocks aldosterone receptors • Binds with receptors for other steroid hormones • Therapeutic uses • Hypertension • Heart failure

  22. Aldosterone Antagonists • Spironolactone (Aldactone) (cont’d) • Adverse effects • Hyperkalemia • Gynecomastia • Menstrual irregularities • Impotence • Hirsutism • Deepening of the voice

More Related