Antihypertensive Drugs

Mechanisms Regulating Blood Pressure Neural Neural Hormonal Hormonal Vascular Vascular Vascular Remodeling Vascular Remodeling

Neural Triggered by hypotension & inadequate tissue perfusion Triggered by hypotension & inadequate tissue perfusion Release of epinephrine & norepinephrine causing Release of epinephrine & norepinephrine causing Constriction of blood vessels in the skin, kidney, & GIConstriction of blood vessels in the skin, kidney, & GI The heart rate and the force of the contractionThe heart rate and the force of the contraction

Hormonal Renin-Angiotensin-Aldosterone System & Vasopressin Renin is released in response to Renin is released in response to ________________ Renin converts angiotensinogen to angiotensin I Renin converts angiotensinogen to angiotensin I Angiontensin-converting enzyme (ACE) produces angiontensin II Angiontensin-converting enzyme (ACE) produces angiontensin II

Renin-Angiotensin-Aldosterone

Renin-Angiotensin- Aldosterone Please follow the following link and review this material

Angiontensin II Strongly constricts arterioles Strongly constricts arterioles Increases/Decreases? peripheral vascular resistance Increases/Decreases? peripheral vascular resistance Increases BP by direct vasoconstriction, stimulation of the SNS, and stimulation of catecholamine release Increases BP by direct vasoconstriction, stimulation of the SNS, and stimulation of catecholamine release Stimulates secretion of Aldosterone Stimulates secretion of Aldosterone

Aldosterone Kidneys retain sodium and H2O Kidneys retain sodium and H2O Retention of sodium and water increases () Retention of sodium and water increases () ______ ___________ _____

Vasopressin Antidiuretic Hormone (ADH) Regulates _______ reabsorption by the kidneys Regulates _______ reabsorption by the kidneys Released in response to decreased blood volume and blood pressure Released in response to decreased blood volume and blood pressure Causes Causes Retention of fluidsRetention of fluids vasoconstrctionvasoconstrction

Vascular Endothelium damage Endothelium damage Production of vasoconstrictor Production of vasoconstrictor Inability to respond to vasodialators Inability to respond to vasodialators

Vascular Remodeling Endothelial damage Endothelial damage Stimulates growth of smooth muscle cells Stimulates growth of smooth muscle cells Vessel is thickened Vessel is thickened Lumen is narrowed Lumen is narrowed Less flexible Less flexible

Primary Hypertension Unknown etiology Unknown etiology One or more of the compensatory mechanisms has gone awry One or more of the compensatory mechanisms has gone awry

Hypertension Definition pg 353 Definition pg 353

Target Organs

Antihypertensive Drugs Primary Hypertension Angitensinconverting enzyme (ACE) Inhibitors (yes) Angitensinconverting enzyme (ACE) Inhibitors (yes) Angitensin II Receptor Antagonists (no) Angitensin II Receptor Antagonists (no) Antiandrenergics (yes) Antiandrenergics (yes) Calcium Channel Blockers (yes) Calcium Channel Blockers (yes) Diuretics (yes) Diuretics (yes)

Angiotensin-Converting Enzyme Inhibitors (ACE Inhibitors) Block the enzyme that converts angiotensin I to angiontensin II Block the enzyme that converts angiotensin I to angiontensin II Decrease vasoconstriction Decrease vasoconstriction Decrease aldosterone production Decrease aldosterone production Prevent or reverse remodeling of heart and vessels Prevent or reverse remodeling of heart and vessels

ACE Inhibitors Caucasians-May be effective alone Caucasians-May be effective alone African-Americans maybe used in combination with diuretic African-Americans maybe used in combination with diuretic

ACE Inhibitor Prototype Captopril (Capoten) Choice for diabetic nephropathy Choice for diabetic nephropathy Renal protective Renal protective DOC for clients with CHF DOC for clients with CHF 23-4 p p. 363

Side Effects % experience persistent cough % experience persistent cough Hypotension Hypotension Hyperkalemia Hyperkalemia Renal failure Renal failure Sexual dysfunction Sexual dysfunction

Contraindications Pregnancy Pregnancy

Nursing Assessment Check BP accurately and repeatedly Check BP accurately and repeatedly Monitor renal function Monitor renal function Hyperkalemia Hyperkalemia Jaundice Jaundice

Teaching Give one hour ac Give one hour ac Continue to take even if feeling well Continue to take even if feeling well Antacids 2 hours before or after Antacids 2 hours before or after

Beta Blockers 269, Lilley Decrease Heart rate Heart rate Force of myocardial contraction Force of myocardial contraction Cardiac output Cardiac output O 2 Demand by the heart O 2 Demand by the heart Renin release from the kidney Renin release from the kidney Stimulation from SNS Stimulation from SNS

Beta Blocker Drug of first choice <50 with high renin hypertension <50 with high renin hypertension Tachycardia Tachycardia Angina Angina MI MI Left ventricular hypertrophy Left ventricular hypertrophy

Beta Blocker Greater effect on Asians Greater effect on Asians African-American part of multi-drug regimen African-American part of multi-drug regimen

Beta Blocker Prototype Lopressor Available PO & IV Available PO & IV Available in extended release Available in extended release Cardio selective beta blocker Cardio selective beta blocker

Side Effects Fatigue Fatigue Bradycardia Bradycardia CHF CHF Pulmonary Edema Pulmonary Edema Impotence Impotence

Nursing Assessment Monitor BP, ECG, Pulse Monitor BP, ECG, Pulse I & O & daily weights I & O & daily weights BUN BUN Liver function Liver function

Teaching Pulse & BP at home Pulse & BP at home May cause drowsiness May cause drowsiness Drug must be tapered Drug must be tapered Impotence Impotence Weight gain >2lb/wk Weight gain >2lb/wk

Use Carefully Hepatic Impairment Hepatic Impairment Renal Impairment Renal Impairment

Calcium Channel Blockers Used for several CV disorders Used for several CV disorders In hypertension In hypertension Dilate peripheral arteriesDilate peripheral arteries Decrease vascular resistanceDecrease vascular resistance Choice for clients with angina Choice for clients with angina Can use for renal impairment Can use for renal impairment Use with caution with hepatic impairment Use with caution with hepatic impairment

Calcium Channel Blockers Prototype: Diltiazem (Cardizem SR) Prevent movement of extracellular Ca into the cell Prevent movement of extracellular Ca into the cell SR? SR? Slows the AV node Slows the AV node Decreases systemic vascular pressure Decreases systemic vascular pressure

Contraindications 2 nd and 3 rd degree heart block 2 nd and 3 rd degree heart block Cardiogenic shock Cardiogenic shock Congestive heart failure Congestive heart failure Severe bradycardia Severe bradycardia Hypotension Hypotension

Side effects Diltiazem (Cardizem SR) Peripheral edema Peripheral edema Arrhythmias Arrhythmias CHF CHF Stevens Johnson Syndrome Stevens Johnson Syndrome

Teaching Do not crush, break, or chew Do not crush, break, or chew With or without meals With or without meals May cause drowsiness May cause drowsiness Photosensitivity Photosensitivity

Nursing Implications All Antihypertensives Therapeutic Goal of tx is usually 140/90 Goal of tx is usually 140/90 Adverse Effects Monitor postural hypotension Monitor postural hypotension I & O I & O Bradycardia Bradycardia Antiacids, andrenergics, & NSAIDS Antiacids, andrenergics, & NSAIDS

Diuretics Renal Physiology Nephron processes (pg 378) Nephron processes (pg 378) ______ ____________ ______ Maintain fluid volume, electrolyte concentration, & pH Maintain fluid volume, electrolyte concentration, & pH Cellular waste Cellular waste 400 ml/d 400 ml/d

Glomerular Filtration Pressure pushes H2O, electrolytes other solutes out Pressure pushes H2O, electrolytes other solutes out End product is approx 2L urine/d End product is approx 2L urine/d

Tubular Reabsorption Most occurs in proximal tubule Most occurs in proximal tubule Glucose, amino acids, and approx 80% of H2O, Sodium, Potassium, & ChlorideGlucose, amino acids, and approx 80% of H2O, Sodium, Potassium, & Chloride Loop of Henle Loop of Henle Descending limb H2ODescending limb H2O Ascending SodiumAscending Sodium Distal Tubule Distal Tubule Exchange sodium & potassiumExchange sodium & potassium H2OH2O

Antidiuretic Hormone (ADH) & Aldosterone ADH promotes reabsorption of ____ ADH promotes reabsorption of ____ Urine becomes more concentrated Urine becomes more concentrated Aldosterone promotes sodium- potassium exchange Aldosterone promotes sodium- potassium exchange Promotes sodium retention and potassium loss Promotes sodium retention and potassium loss

Tubular Secretion Proximal tubule Proximal tubule Uric acid, Cr, Hydrogen ions, & ammoniaUric acid, Cr, Hydrogen ions, & ammonia Distal tubule Distal tubule Potassium ions, hydrogen ions, & ammoniaPotassium ions, hydrogen ions, & ammonia Hydrogen balance maintains pH

Diuretics Decrease blood pressure by sodium & water depletion Decrease blood pressure by sodium & water depletion Initially, BV & CO are decreased Initially, BV & CO are decreased Eventually, CO normalizes but vascular resistance is decreased Eventually, CO normalizes but vascular resistance is decreased May be used alone or in combination with anti-hypertensives May be used alone or in combination with anti-hypertensives

Thiazide Diuretics Chemically related to sulfonamides Chemically related to sulfonamides Decrease reabsorption of sodium, H2O, Chloride, & distal convoluted tubule Decrease reabsorption of sodium, H2O, Chloride, & distal convoluted tubule Not a strong diuretic Not a strong diuretic Ineffective for immediate diuresis Ineffective for immediate diuresis DOC for long term management DOC for long term management

Thiazide Prototype Hydrochorothiazide (Hydrodiuril) Diuresis in about 2 hours Diuresis in about 2 hours Promotes excretion of chloride, potassium, magnesium, & bicarb Promotes excretion of chloride, potassium, magnesium, & bicarb

Contraindications Allergy to ____ Allergy to ____ Pregnancy Pregnancy

Loop Diuretics Inhibit sodium & chloride reabsorption at the ascending limb of the loop of Henle Inhibit sodium & chloride reabsorption at the ascending limb of the loop of Henle Significant diuresis, w/i 5 min (IV) Significant diuresis, w/i 5 min (IV) High ceiling High ceiling Postdiuretic phase may absorb more sodium Postdiuretic phase may absorb more sodium DOC in impaired renal function DOC in impaired renal function

Loop Diuretic Prototype Furosimide (Lasix) Most commonly used Most commonly used Do not give if discolored Do not give if discolored Ototoxicity Ototoxicity

Side Effect Hypokalemia Serum potassium levels (what is normal?) Serum potassium levels (what is normal?) EKG EKG Hypotension Hypotension N&V, anorexia N&V, anorexia Muscle weakness Muscle weakness Confusion Confusion

Teaching Diuretics Avoid excess table salt Avoid excess table salt Periodic serum potassium levels Periodic serum potassium levels Increase potassium rich foods Increase potassium rich foods Diabetic? Diabetic? Photosensitivity Photosensitivity Change positions slowly Change positions slowly Take with food Take with food

Potassium Sparing Diuretics Distal tubule to decrease sodium reabsorption and potassium excretion Distal tubule to decrease sodium reabsorption and potassium excretion Weak diuretic Weak diuretic Usually in combination Usually in combination

Potassium Sparing Diuretics Prototype: Spironolactone (Aldactone) Aldosterone antagonist Aldosterone antagonist Major side effect hyperkalemia Major side effect hyperkalemia Do not use with renal insufficiency Do not use with renal insufficiency

Teaching No salt substitutes No salt substitutes No potassium supplements No potassium supplements

Contraindications Renal failure Renal failure

Nursing Implications All Diuretics Give in AM Give in AM I & O, daily weights, BP I & O, daily weights, BP Assess for edema Assess for edema Monitor for coughing Monitor for coughing Skin turgor Skin turgor Hyperglycemia Hyperglycemia Hyperuricemia Hyperuricemia Pulmonary edema Pulmonary edema

Potassium Sparing Hyperkalemia Potassium over ?Potassium over ? ECG changesECG changes ArrhythmiasArrhythmias

Questions The nurse is explaining HTN to a client. Which is the best explanation for why hypertension develops? A) “Americans have a poor diet” B) “Its is because of your sedentary lifestyle” C) “we really don’t understand the reasons behind hypertension” D) “one or more of the body’s compensatory systems has gone awry”

Questions A client with an order for Furosimide (Lasix) is experiencing hypokalemia. What should the nurse do? A) Give the Furosimide with a K+ supplement B) Give Spironolactone (Aldactone) STAT C) Hold the Furosimide D) Call the lab