Drugs Affecting Blood Pressure PDF
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2023
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This document is a chapter on drugs affecting blood pressure. It covers hypertension, hypotension, and related conditions. It details various drug types, their mechanisms of action, and implications.
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Chapter 43 Drugs Affecting Blood Pressure Copyright Copyright © 2012 © 2017 Wolters Wolters Kluwer Kluwer All Health |...
Chapter 43 Drugs Affecting Blood Pressure Copyright Copyright © 2012 © 2017 Wolters Wolters Kluwer Kluwer All Health | Lippincott Rights Reserved Williams & Wilkins Blood Pressure Control Mean arterial pressure determined by o Heart rate o Stroke volume: amount of blood pumped out of the ventricle with each heartbeat o Total peripheral resistance: resistance of the muscular arteries to the blood being pumped through Autonomic nervous system Baroreceptors Renin–angiotensin–aldosterone system Copyright © 2023 Wolters Kluwer All Rights Reserved Control of Blood Pressure Copyright © 2023 Wolters Kluwer All Rights Reserved The Renin–Angiotensin–Aldosterone System Copyright © 2023 Wolters Kluwer All Rights Reserved Hypertension Person’s BP is above normal limit for sustained period o 90% have essential or primary hypertension Underlying danger o Body organ damage o Increased risk of atherosclerotic vascular disease o Thickening of heart muscle Difficult to diagnose and treat; “silent killer” Copyright © 2023 Wolters Kluwer All Rights Reserved Conditions Related to Untreated Hypertension CAD and cardiac death Stroke Renal failure Loss of vision Copyright © 2023 Wolters Kluwer All Rights Reserved Risk Factors Associated With Hypertension Increased age Cigarette smoking High-salt diet High intake of alcohol Low physical fitness Obesity Insulin resistance Psychological stress Obstructive sleep apnea Family history Copyright © 2023 Wolters Kluwer All Rights Reserved Hypotension BP becomes too low Vital centers in brain and rest of tissues in body may not receive enough oxygenated blood to function Can progress to shock Can occur in following situations: o Heart muscle is damaged and unable to pump effectively o Severe blood or fluid loss, when volume drops dramatically o Impairment of autonomic nervous system to increase cardiac output, vascular resistance, or both o Medication-induced hypotension Copyright © 2023 Wolters Kluwer All Rights Reserved Orthostatic Hypotension Lowering of BP when person sits up from lying down or stands from sitting position May be accompanied by dizziness, light-headedness, nausea, changes in vision, and/or syncope o Symptoms caused by decrease in blood flow to brain tissue Increased risk o Older adults o Use of certain medications Copyright © 2023 Wolters Kluwer All Rights Reserved Use of Drugs Affecting Blood Pressure Across the Lifespan #1 Copyright © 2023 Wolters Kluwer All Rights Reserved Use of Drugs Affecting Blood Pressure Across the Lifespan #2 Copyright © 2023 Wolters Kluwer All Rights Reserved Stepped Care Management of Hypertension Step 1: Lifestyle modifications Step 2: Drug therapy added Step 3: Change in drug dose or class or addition of another drug Step 4: Second or third agent or diuretic is added Copyright © 2023 Wolters Kluwer All Rights Reserved Antihypertensive Agents Work to alter normal reflexes that control BP Not all patients respond in same way to antihypertensive drugs because of different factors and complicating conditions Several different types of medication may need to be used in combination Drugs include o ACE inhibitors o Angiotensin II receptor blockers (ARBs) o Calcium-channel blockers o Vasodilators o Other agents Copyright © 2023 Wolters Kluwer All Rights Reserved Drugs Affecting the RAAS ACE inhibitors ARBs Renin inhibitor Copyright © 2023 Wolters Kluwer All Rights Reserved ACE Inhibitors #1 Benazepril (Lotensin) Lisinopril (Prinivil, Zestril, Qbrelis) Captopril (generic) Moexipril (generic) Enalapril (Epaned, Vasotec) Perindopril (generic) Enalaprilat (generic) Quinapril (Accupril) Fosinopril (generic) Ramipril (Altace) Trandolapril (generic) Copyright © 2023 Wolters Kluwer All Rights Reserved ACE Inhibitors #2 Therapeutic actions o Act in lungs to prevent ACE from converting angiotensin I to angiotensin II, leading to a decrease in blood pressure and in aldosterone production; results in increase in serum potassium and loss of serum sodium and fluid Indications o Treatment of hypertension, heart failure, left ventricular dysfunction, diabetic nephropathy Pharmacokinetics o Well absorbed, widely distributed, metabolized in the liver, and excreted in the urine and feces o Cross placenta and enter human milk Copyright © 2023 Wolters Kluwer All Rights Reserved ACE Inhibitors #3 Contraindications o History of allergic reaction o Impaired renal function o Acute heart failure exacerbation o Salt/volume depletion o Pregnancy and lactation Copyright © 2023 Wolters Kluwer All Rights Reserved ACE Inhibitors #4 Adverse effects o Related to the effects of vasodilatation and alterations in blood flow o Generally well tolerated o Serious allergic reactions including angioedema o Hyperkalemia o Captopril, moexipril, perindopril: more serious effects Copyright © 2023 Wolters Kluwer All Rights Reserved ACE Inhibitors #5 Drug–drug interactions o Allopurinol o NSAIDs o Diuretics and other antihypertensive medications o Potassium supplements and potassium-sparing diuretics o Lithium o Drugs that alter RAAS o Other ACE inhibitors, ARBs, renin inhibitor Copyright © 2023 Wolters Kluwer All Rights Reserved ACE Inhibitor Prototype Copyright © 2023 Wolters Kluwer All Rights Reserved Question #1 Please answer the following questions as true or false. The use of a loop diuretic is the first drug used in the stepped care management of hypertension. Copyright © 2023 Wolters Kluwer All Rights Reserved Answer to Question #1 False Rationale: The first step in stepped care management of hypertension involves lifestyle modifications. A diuretic may be added in step 2. Copyright © 2023 Wolters Kluwer All Rights Reserved Angiotensin II Receptor Blockers #1 Azilsartan (Edarbi) Candesartan (Atacand) Irbesartan (Avapro) Losartan (Cozaar) Olmesartan (Benicar) Telmisartan (Micardis) Valsartan (Diovan) Copyright © 2023 Wolters Kluwer All Rights Reserved Angiotensin II Receptor Blockers #2 Therapeutic actions o Selectively bind with the angiotensin II receptors in vascular smooth muscle and in the adrenal cortex to block vasoconstriction and the release of aldosterone o These actions block BP-raising effects of the RAAS and lower BP Indications o Used alone or in combination to treat hypertension o Some indicated for treatment of heart failure and after MI o Some have been found to slow progression of renal disease Copyright © 2023 Wolters Kluwer All Rights Reserved Angiotensin II Receptor Blockers #3 Pharmacokinetics o Well absorbed; undergo metabolism in the liver by the cytochrome P450 system; excreted in the feces and urine o Cross the placenta o Not known if they enter human milk Copyright © 2023 Wolters Kluwer All Rights Reserved Angiotensin II Receptor Blockers #4 Contraindications o Allergy o Pregnancy and lactation Cautions o Hepatic or renal dysfunction o Hypovolemia Copyright © 2023 Wolters Kluwer All Rights Reserved Angiotensin II Receptor Blockers #5 Adverse effects o Headache, dizziness, syncope, weakness o GI complaints o Dry mouth and tooth pain o Symptoms of upper respiratory infections and cough o Rash, dry skin, alopecia Drug–drug interactions o Other antihypertensive medications o Potassium supplements or potassium-sparing diuretic medication o Lithium o NSAIDs Copyright © 2023 Wolters Kluwer All Rights Reserved Angiotensin II Receptor Blocker Prototype Copyright © 2023 Wolters Kluwer All Rights Reserved Renin Inhibitor #1 Aliskiren (Tekturna) Therapeutic action o Directly inhibits renin, leading to decreased plasma renin activity and inhibiting the conversion of angiotensinogen to angiotensin I Pharmacokinetics o Poorly and slowly absorbed from GI tract, metabolized in the liver, excreted in the urine o Crosses the placenta and enters human milk Copyright © 2023 Wolters Kluwer All Rights Reserved Renin Inhibitor #2 Contraindications o Pregnancy and lactation Adverse effects o Risk of hyperkalemia o Angioedema with respiratory involvement o Renal impairment Drug–drug Interactions o Furosemide o Other antihypertensive medications o ACE inhibitors, ARBs, potassium-sparing diuretics Copyright © 2023 Wolters Kluwer All Rights Reserved Calcium-Channel Blockers #1 Decrease BP, cardiac o Nifedipine (Procardia XL) work load, myocardial o Nisoldipine (Sular) oxygen consumption o Verapamil (Calan SR) Drugs o Clevidipine (Cleviprex): o Amlodipine (Katerzia, IV only for short-term Norvasc) management o Diltiazem (Cardizem LA, Cartia XT, others) o Felodipine (generic) o Isradipine (generic) o Nicardipine (generic) Copyright © 2023 Wolters Kluwer All Rights Reserved Calcium-Channel Blockers #2 Therapeutic actions o Inhibit movement of calcium ions across the membranes of myocardial and arterial muscle cells, altering action potential and blocking muscle cell contraction Indications o Treatment of hypertension, angina Pharmacokinetics o Well absorbed, metabolized in the liver, and excreted in the urine o Cross the placenta and enter human milk Copyright © 2023 Wolters Kluwer All Rights Reserved Calcium-Channel Blockers #3 Contraindications o Allergy o Nondihydropyridine calcium-channel blockers: heart block or sick sinus syndrome, heart failure, acute MI o Pregnancy and lactation Adverse effects o Related to effects on cardiac output o CNS effects o GI effects o CV effects o Skin flushing and rash Copyright © 2023 Wolters Kluwer All Rights Reserved Calcium-Channel Blockers #4 Drug–drug interactions o Vary with each drug Drug–food interactions o Grapefruit juice Copyright © 2023 Wolters Kluwer All Rights Reserved Calcium-Channel Blocker Prototype Copyright © 2023 Wolters Kluwer All Rights Reserved Question #2 The mechanism of action of an ACE inhibitor is the blocking of ACE from converting angiotensin I to angiotensin II. What does this cause? A. Decrease in serum potassium levels B. Decrease in aldosterone secretion C. Increase in serum sodium and fluid D. Increase in blood pressure Copyright © 2023 Wolters Kluwer All Rights Reserved Answer to Question #2 B. Decrease in aldosterone secretion Rationale: ACE inhibitors act in the lungs to prevent ACE from converting angiotensin I to angiotensin II, a powerful vasoconstrictor and stimulator of aldosterone release. This action leads to a decrease in BP and in aldosterone secretion with a resultant increase in serum potassium and a loss of serum sodium and fluid. Copyright © 2023 Wolters Kluwer All Rights Reserved Vasodilators #1 Most are reserved for use in severe hypertension, refractory hypertension, or hypertensive emergencies Drugs o Hydralazine (generic) o Minoxidil (generic) o Nitroglycerin (generic) o Nitroprusside (Nitropress) Copyright © 2023 Wolters Kluwer All Rights Reserved Vasodilators #2 Therapeutic actions o Act directly on vascular smooth muscle to cause muscle relaxation, leading to vasodilatation and drop in BP Indications o Severe hypertension that has not responded to other therapy Pharmacokinetics o Rapidly absorbed and widely distributed, metabolized in the liver, and primarily excreted in the urine o Cross placenta and enter human milk Copyright © 2023 Wolters Kluwer All Rights Reserved Vasodilators #3 Contraindications o Known allergy o Any condition that could be exacerbated by sudden fall in BP o Pregnancy and lactation Cautions o Peripheral vascular disease o CAD o Heart failure o Tachycardia Copyright © 2023 Wolters Kluwer All Rights Reserved Vasodilators #4 Adverse effects o Related to changes in BP o Cyanide toxicity Drug–drug interactions o Varies by individual drug; check each before use Copyright © 2023 Wolters Kluwer All Rights Reserved Vasodilator Prototype Copyright © 2023 Wolters Kluwer All Rights Reserved Diuretics Increase excretion of sodium and water from the kidney to lower BP See Chapter 51 for detailed discussion of these agents Often one of the first agents tried in mild hypertension Usually tolerated well by most patients Diuretics used to treat hypertension: o Thiazide and thiazidelike diuretics o Potassium-sparing diuretics Copyright © 2023 Wolters Kluwer All Rights Reserved Sympathetic Nervous System Blockers Block effects of sympathetic nervous system See Chapter 31 for detailed discussion of these agents Drugs: o Beta-blockers o Alpha- and beta-blockers o Alpha-adrenergic blockers o Alpha1-blockers o Alpha2-agonists Copyright © 2023 Wolters Kluwer All Rights Reserved Question #3 For which drug will the nurse need to caution patients against drinking grapefruit juice? A. Irbesartan (Avapro) B. Aliskiren (Tekturna) C. Clevidipine (Cleviprex) D. Moexipril (generic) Copyright © 2023 Wolters Kluwer All Rights Reserved Answer to Question #3 C. Clevidipine (Cleviprex) Rationale: Clevidipine (Cleviprex) is a calcium- channel blocker. The calcium-channel blockers are a class of drugs that interact with grapefruit juice. When grapefruit juice is present in the body, the concentrations of calcium-channel blockers increase, sometimes to toxic levels. Advise patients to avoid drinking grapefruit juice if they are taking a calcium- channel blocker. If a patient on a calcium-channel blocker reports toxic effects, ask whether they have been drinking grapefruit juice. Copyright © 2023 Wolters Kluwer All Rights Reserved Antihypotensive Agents Sympathetic adrenergic agonists or vasopressors Blood pressure–raising agents Droxidopa (Northera) Copyright © 2023 Wolters Kluwer All Rights Reserved Sympathetic Adrenergic Agonists or Vasopressors #1 First choice for treating severe hypotension or shock Sympathomimetic drugs discussed in detail in Chapter 30 Therapeutic actions and indications o React with sympathetic adrenergic receptors to cause effects of sympathetic stress response o Increase BP and may restore balance to CV system while underlying cause of shock is treated Copyright © 2023 Wolters Kluwer All Rights Reserved Sympathetic Adrenergic Agonists or Vasopressors #2 Adverse effects o Effects of stimulation of sympathetic system o Use with caution with any disease that limits blood flow Drug–drug interactions o Other agents that increase HR and BP Copyright © 2023 Wolters Kluwer All Rights Reserved Blood Pressure–Raising Agent: Midodrine #1 Therapeutic actions and indications o Activates alpha-receptors in arteries and veins to produce increase in vascular tone, increase in BP o Symptomatic treatment of orthostatic hypotension in patients whose lives are impaired by the disorder and who have not responded to other therapy Pharmacokinetics o Rapidly absorbed from GI tract; metabolized in liver and excreted in urine o Not known if it enters human milk Copyright © 2023 Wolters Kluwer All Rights Reserved Blood Pressure–Raising Agent: Midodrine #2 Contraindications o Supine hypotension or pheochromocytoma Cautions o Severe heart disease o Acute renal disease o Urinary retention o Thyrotoxicosis o Pregnancy and lactation o Visual problems o Renal or hepatic impairment Copyright © 2023 Wolters Kluwer All Rights Reserved Blood Pressure–Raising Agent: Midodrine #3 Adverse effects o Related to stimulation of alpha-receptors Drug–drug interactions o Cardiac glycosides, beta-blockers, alpha- adrenergic agents, corticosteroids Copyright © 2023 Wolters Kluwer All Rights Reserved Droxidopa #1 Indicated for treatment of orthostatic dizziness, light- headedness, “about to black out” feeling in adults with symptomatic neurogenic orthostatic hypotension Therapeutic actions and indications o Metabolized to norepinephrine by dopa decarboxylase o Actions on BP thought to be related to norepinephrine effects causing vasoconstriction Pharmacokinetics o Absorbed through GI tract; widely distributed; metabolized by normal catecholamine pathways; excreted in urine Copyright © 2023 Wolters Kluwer All Rights Reserved Droxidopa #2 Contraindications o History of allergy Cautions o History of CV issues o Renal impairment o Breast or chestfeeding Adverse effects o Related to sympathetic effects of the drug Drug–drug interactions o Dopa decarboxylase inhibitors Copyright © 2023 Wolters Kluwer All Rights Reserved