Chapter 22.2 | Quizalize

Chapter 22 Antihypertensive Drugs Hypertension Defined (JNC-8) Pharmacology Overview 7 main categories of drugs to treat HTN Adrenergic drugs (old friend) Angiotensin-converting enzyme (ACE) inhibitors Angiotensin II receptor blockers (ARBs) Calcium channel blockers (CCBs) Diuretics Vasodilators Direct renin inhibitors A. Adrenergic Drugs: 5 Subcategories and where they act A1. Adrenergic neuron blockers (central and peripheral)- we won’t talk about this A2. Alpha1 receptor blockers (peripheral) A3. Alpha2 receptor agonists (central) A4. Beta receptor blockers (peripheral) A5. Combined α and β receptor blockers (peripheral) A2. Peripherally Acting Adrenergic DrugAlpha1 Blockers (we’ve met these) Doxazosin, prazosin, alfuzosin Block alpha1-receptors which causes BP to decrease Reduces peripheral vascular resistance and BP by dilating both arterial and venous blood vessels Main Use: benign prostatic hyperplasia (BPH) Alpha1 Blockers REMEMBER Tamsulosin (Flomax)* is an α1 blocker BUT *Tamsulosin is not used to control BP, just for BPH. A3. Centrally Acting Adrenergic DrugsAlpha 2 agonist Clonidine and methyldopa 1- Stimulate alpha2-adrenergic receptors. in the brain Decreases sympathetic outflow from the CNS which decreases NE production 2. Stimulate alpha2-adrenergic receptors in kidneys remember alpha 2 opposes alpha 1 Dilates peripheral blood vessels → lowers peripheral resistance → Results in decreased BP So ….Clonidine (Catapres) Used primarily for its ability to decrease blood pressure in an urgent setting Also use in opioid withdrawal as previously discussed Oral (multiple times a day), and topical patch formulations Do not stop abruptly as it may lead to rebound hypertension In reality, Clonidine and methyldopa Not prescribed as first-line home antiHTN drugs High incidence of unwanted adverse effects: orthostatic hypotension, fatigue, and dizziness MIGHT be uses as adjunct drugs after other drugs have failed, in conjunction with other antiHTN such as diuretics A4. Adrenergic Drugs Selective Beta 1 Blockers Metoprolol, Atenolol Reduction of HR through β1 receptor blockade (remember adrenergic blocking of this receptor???) HR results in BP Cause reduced secretion of renin = BP A4. Adrenergic Drugs Selective Beta1 Blockers Nebivolol (Bystolic) Uses: hypertension and HF Action: blocks β1 receptors and produces vasodilatation, which results in a decrease in SVR High doses loses selectivity and blocks both β1 and β2 Less sexual dysfunction All BB- Do not stop abruptly; must be tapered over 1 to 2 weeks A4. Adrenergic Drugs NONSelective Beta Blockers Propranolol Acts equally on β1 and β2 Other uses include situational anxiety associated with public speaking, test taking As mentioned on previous slide, nebivolol at high doses becomes beta nonselective A5. Dual-Action Adrenergic Drugs α1 and β Receptor Blockers Dual antihypertensive effects of reduction in heart rate (beta1 receptor blockade) and vasodilation (alpha1 receptor blockade) Examples are carvedilol (common) and labetalol (not as common) A5. Dual-Action Adrenergic Drugs α1 and β Receptor Blockers Carvedilol (Coreg) Widely used drug that is well tolerated Uses: HTN, mild to moderate HF in conjunction with digoxin, diuretics, and ACE inhibitors Contraindications: severe bradycardia or unstable HF, bronchospastic conditions such as asthma, and various cardiac conduction problems Adrenergic Drugs Indications - HTN But also for Glaucoma (topical) BPH: doxazosin, prazosin, and terazosin (2 for 1) Management of severe HF when used with cardiac glycosides and diuretics Contraindications Acute HF- have to stabilize first MOAIs- yeah doesn’t everything interact with MAOIs? Peptic ulcers Severe liver/kidney disease Asthma (with beta blockers) Adrenergic Drugs: Adverse Effects Orthostatic hypotension 1st-dose syncope Rebound hypertension with abrupt discontinuation Most common: Dry mouth, drowsiness, constipation, sedation Interactions- always check for specific drug interactions Can cause additive CNS depression with alcohol, benzodiazepines, opioids Question #1 When administering an alpha-adrenergic drug for hypertension, it is most important for the nurse to assess the patient for the development of what response? Hypotension Hyperkalemia Oliguria Respiratory distress Answer A Hypotension This is a key point in patient education These drugs have strong vasodilating properties and may cause severe hypotension, especially at the beginning of therapy. B. Angiotensin-Converting Enzyme Inhibitorsaka ACE Inhibitors or ACEi Large group of safe and effective drugs Currently are 10 ACEi Often used as first-line drugs for HF and hypertension May be combined with a thiazide diuretic, loop diuretic, or Calcium Channel Blocker (CCB) You need to understand the basics ACE Inhibitors: Review RAAS ACE converts angiotensin I, formed through the action of renin, to angiotensin II Angiotensin 2 is a potent vasoconstrictor and also induces aldosterone secretion by the adrenal glands Aldosterone stimulates sodium resorption (H20 follows Na Both act to raise BP which causes kidneys to reduce renin production ACEi= Great drug to treat HTN BUT contraindicated in pregnancy (2nd,3rd trimester due to fetal renal damage) and breastfeeding first few weeks after birth B. ACE Inhibitors - PRIL Lisinopril (Prinivil) super common, often the 1st drug Enalapril (Vasotec) also common Captopril (Capoten) great if liver disease present Benazepril (Lotensin) Fosinopril (Monopril) Perindopril (Aceon) Quinapril (Accupril) Ramipril (Altace) Trandolapril (Mavik) Primary Effects of the ACE Inhibitors Prevent Na (and H2O) resorption by inhibiting aldosterone secretion (volume reduction) (GO BACK TO RAAS DIAGRAM) blood volume decreases work of the heart preload, or the left ventricular end-diastolic volume which is important in HF ACE SUMMARY OF ACTIVITY 1) Prevent vasoconstriction caused by angiotensin 2 (2) Prevent aldosterone secretion  less sodium and water resorption Cardioprotective Effects of ACEi They slow progression of left ventricular hypertrophy (ventricular remodeling) after MI so considered cardioprotective ACE inhibitors have been shown to decrease morbidity and mortality in patients with HF Renal Protective Effects of ACEi ACE inhibitors: reduce glomerular filtration pressure by volume reduction Cardiovascular drug of choice for patients with diabetes since it helps protect kidneys by reducing pressure. Sometimes used low dose for kidney protection with DM without HTN B. ACEi Enalapril (Vasotec) Only ACEi available in both oral and IV Enalapril IV does not require cardiac monitoring Oral enalapril: prodrug (metabolized in liver) Improves patient’s chances of survival after an MI Reduces the incidence of HF B. ACEi Captopril (Capoten) Uses: prevention of ventricular remodeling after MI; reduce the risk of HF after MI Shortest half-life Must be administered multiple times throughout the day so this limits its use Not a prodrug so good for patient with liver disease Question #2 A patient with diabetes has a new prescription for the ACE inhibitor lisinopril. She questions this order because her provider has never told her that she has hypertension. What is the best explanation for this order? The doctor knows best The patient is confused This medication has cardioprotective properties This medication has a protective effect on the kidneys for patients with diabetes Answer D ACE inhibitors have been shown to have a protective effect on the kidneys because they reduce glomerular filtration pressure. This property makes them the cardiovascular drug of choice for patients with diabetes. Question #3 A patient with a history of pancreatitis and cirrhosis is also being treated for hypertension. Which drug will most likely be ordered for this patient? Clonidine Prazosin Diltiazem Captopril Answer D Captopril Captopril is not a prodrug; therefore, it does not need to be metabolized by the liver to be effective. This is an advantage in patients with liver disease. ACE Inhibitors: Adverse Effects *Dry, nonproductive cough, which reverses when therapy is stopped. This is a class effect Dizziness- Note: First-dose hypotensive effect may occur Headache & Fatigue Possible hyperkalemia ** Angioedema: rare but potentially fatal Not safe in pregnancy-are contraindicated during the second and third trimesters of pregnancy because of increased risk of fetal renal damage C. Angiotensin II Receptor Blockers(ARB) Considered an alternative to ACEi Less likely to cause a dry cough and hyper K+ that is common with ACE inhibitors Angiotensin II Receptor Blockers: Mechanism of Action Go back to RAAS diagram! ARBs affect primarily 2 places 1. Vascular smooth muscle - blocks vasoconstriction 2. Adrenal gland -Selectively blocks the binding of Ang 2 to certain Ang 2 receptors inhibiting secretion of aldosterone Lowers volume retention and BP Angiotensin II Receptor Blockers -ARTAN Losartan (Cozaar)- very common Eprosartan (Teveten) Valsartan (Diovan) Irbesartan (Avapro) Candesartan (Atacand) Olmesartan (Benicar) Telmisartan (Micardis) Azilsartan (Edarbi) C. ARB Losartan (Cozaar) Beneficial in patients with HTN and HF Used with caution in patients with kidney or liver dysfunction and in patients with renal artery stenosis ***Not safe for breastfeeding women and should not be used in pregnancy (Cat C 1st trimester, Cat D 2nd-3rd trimester), potential fetal toxicity Appear to be equally effective for the treatment of hypertension and well tolerated ARBs less likely to cause cough and hyperK+ but can still happen Evidence that ARBs are associated with lower mortality after MI than ACE inhibitors Never take ACEi and ARBs at the same time* 5. Calcium Channel Blockers (CCB) Primary use: HTN, angina, some dysrhythmias Cause smooth muscle relaxation by blocking the binding of calcium to its receptors, preventing muscle contraction Results in: Relaxed blood vessels to the heart Decreased peripheral smooth muscle tone Decreased SVResistance Decreased BP E. Diuretics First-line antiHTN in JNC 8 guidelines Decreases fluid volume The results from diuresis: preload, Peripheral resistance Overall effect  Decreased workload of the heart and decreased BP Thiazide diuretics are the most commonly used diuretics for HTN Ie hydrochlorothiazide (HCTZ), chlorthalidone We will discuss diuretics further in the chapter on diuretics F. Vasodilators Directly relax arterial or venous smooth muscle (or both) Results in: Decreased SVR Decreased afterload Peripheral vasodilation Indicated for treatment of HTN May be used in combination with other drugs F. Vasodilators Hydralazine (Apresoline) Orally: routine cases of essential hypertension Injectable: hypertensive emergencies BiDil: specifically indicated as an adjunct for treatment of HF in African-American patients F. Vasodilators Sodium Nitroprusside (Nitropress) *Sodium nitroprusside and IV diazoxide are reserved for the management of hypertensive emergencies. Contraindications: severe HF, known inadequate cerebral perfusion (especially during neurosurgical procedures) F. Vasodilators Adverse Effects Hydralazine: dizziness, headache, tachycardia, edema, dyspnea, N/V/D, vitamin B6 deficiency, rash Sodium nitroprusside: hypotension, bradycardia, decreased platelet aggregation, rash G. Direct Renin Inhibitors Aliskirin (Tekturna) Blocks the RAS pathway at the point of activation. Inhibiting renin production prevents the downstream production of Ang II (potent vasoconstrictor) Adverse effects: N/V, severe hypotension, hyponatremia, hyperkalemia… Contraindicated in patients with DM taking ACEi or ARB Miscellaneous Antihypertensives Eplerenone (Inspra) Newer class of drugs called selective aldosterone blockers (remember RAAS?) Reduces BP by blocking the actions of aldosterone at its corresponding receptors in the kidney, heart, blood vessels, and brain Indications: routine treatment of hypertension and for post-MI HF Contraindicated if serum potassium levels are high (above 5.6 mEq/L) A Special Form of HTNTreatment of Pulmonary Hypertension Sildenafil and Tadalafil Commonly used for erectile dysfunction Used for pulmonary hypertension but with different trade names Sildenafil: Revatio* (Viagra for ED) Tadalafil: Adcirca* (Cialis for ED)

Acct. 2 Quiz Chapter 22

Chapter 19 to 22 MC AP Stat part 2

Plant cells have three kinds of structures that are not found in animal cells and that are extremely important to plant survival: plastids, central vacuoles, and cell walls. PLANT CELLS Most of the organelles and other parts of the cell just described are common to all eukaryotic cells. However, plant cells have three additional kinds of structures that are extremely important to plant function: cell walls, large central vacuoles, and plastids. To understand why plant cells have structures not found in ani- mal cells, consider how a plant’s lifestyle differs from an animal’s. Plants make their own carbon-containing molecules directly from carbon taken in from the environment. Plant cells take carbon diox- ide gas from the air, and in a process called photosynthesis, they convert carbon dioxide and water into sugars. The organelles and structures in plant cells are shown in Figure 4-21. SECTION 4 OBJECTIVES ● List three structures that are present in plant cells but not in animal cells. ● Compare the plasma membrane, the primary cell wall, and the secondary cell wall. ● Explain the role of the central vacuole. ● Describe the roles of plastids in the life of a plant. ● Identify features that distinguish prokaryotes, eukaryotes, plant cells, and animal cells. VOCABULARY cell wall central vacuole plastid chloroplast thylakoid chlorophyll Chloroplast Golgi apparatus Mitochondrion Cell membrane Nucleolus Nucleus Cytoskeleton Rough endoplasmic reticulum Pore Smooth endoplasmic reticulum Central vacuole Ribosome Cell wall In addition to containing almost all of the types of organelles that animal cells contain, plant cells contain three unique features. Those features are the cell wall, the central vacuole, and plastids, such as chloroplasts. FIGURE 4-21 Copyright © by Holt, Rinehart and Winston. All rights reserved. 88 CHAPTER 4 CELL WALL The cell wall is a rigid layer that lies outside the cell’s plasma membrane. Plant cell walls contain a carbohydrate called cellulose. Cellulose is embedded in a matrix of proteins and other carbohy- drates that form a stiff box around each cell. Pores in the cell wall allow water, ions, and some molecules to enter and exit the cell. Primary and Secondary Cell Walls The main component of the cell wall, cellulose, is made directly on the surface of the plasma membrane by enzymes that travel along the membrane. These enzymes are guided by microtubules inside the plasma membrane. Growth of the primary cell wall occurs in one direction, based on the orientation of the microtubules. Other components of the cell wall are made in the ER. These materials move in vesicles to the Golgi and then to the cell surface. Some plants also produce a secondary cell wall. When the cell stops growing, it secretes the secondary cell wall between the plasma membrane and the primary cell wall. The secondary cell wall is very strong but can no longer expand. The wood in desks and tabletops is made of billions of secondary cell walls. The cells inside the walls have died and disintegrated. CENTRAL VACUOLE Plant cells may contain a reservoir that stores large amounts of water. The central vacuole is a large, fluid-filled organelle that stores not only water but also enzymes, metabolic wastes, and other materials. The central vacuole, shown in Figure 4-22, forms as other smaller vacuoles fuse together. Central vacuoles can make up 90 percent of the plant cell’s volume and can push all of the other organelles into a thin layer against the plasma membrane. When water is plentiful, it fills a plant’s vacuoles. The cells expand and the plant stands upright. In a dry period, the vacuoles lose water, the cells shrink, and the plant wilts. Other Vacuoles Some vacuoles store toxic materials. The vacuoles of acacia trees, for example, store poisons that provide a defense against plant-eating ani- mals. Tobacco plant cells store the toxin nicotine in a storage vacuole. Other vacuoles store plant pigments, such as the colorful pigments found in rose petals. The central vacuole occupies up to 90 percent of the volume of some plant cells. The central vacuole stores water and helps keep plant tissue firm. FIGURE 4-22 Central vacuole Nucleus Chloroplast Copyright © by Holt, Rinehart and Winston. All rights reserved. CELL STRUCTURE AND FUNCTION 89 PLASTIDS Plastids are another unique feature of plant cells. Plastids are organelles that, like mitochondria, are surrounded by a double mem- brane and contain their own DNA. There are several types of plastids, including chloroplasts, chromoplasts, and leucoplasts. Chloroplasts Chloroplasts use light energy to make carbohydrates from carbon dioxide and water. As Figure 4-23 shows, each chloroplast contains a system of flattened, membranous sacs called thylakoids. Thylakoids contain the green pigment chlorophyll, the main mole- cule that absorbs light and captures light energy for the cell. Chloroplasts can be found not only in plant cells but also in a wide variety of eukaryotic algae, such as seaweed. Chloroplast DNA is very similar to the DNA of certain photosyn- thetic bacteria. Plant cell chloroplasts can arise only by the divi- sion of preexisting chloroplasts. These facts may suggest that chloroplasts are descendants of ancient prokaryotic cells. Like mitochondria, chloroplasts are also thought to be the descendants of ancient prokaryotic cells that were incorporated into plant cells through a process called endosymbiosis. Chromoplasts Chromoplasts are plastids that contain colorful pigments and that may or may not take part in photosynthesis. Carrot root cells, for example, contain chromoplasts filled with the orange pigment carotene. Chromoplasts in flower petal cells contain red, purple, yellow, or white pigments. Other Plastids Several other types of plastids share the general features of chloro- plasts but differ in content. For example, amyloplasts store starch. Chloroplasts, chromoplasts, and amyloplasts arise from a common precursor, called a proplastid. Thylakoid Inner membrane Outer membrane chloroplast from the Greek chloros, meaning “pale green,” and plastos, meaning “formed” Word Roots and Origins A chloroplast captures energy from sunlight and uses that energy to convert carbon dioxide and water into sugar and other carbohydrates. FIGURE 4-23 Copyright © by Holt, Rinehart and Winston. All rights reserved. 90 CHAPTER 4 COMPARING CELLS All cells share common features, such as a cell membrane, cyto- plasm, ribosomes, and genetic material. But there is a high level of diversity among cells, as shown in Figure 4-24. There are signifi- cant differences between prokaryotes and eukaryotes. In addition, plant cells have features that are not found in animal cells. Prokaryotes Versus Eukaryotes Prokaryotes differ from eukaryotes in that prokaryotes lack a nucleus and membrane-bound organelles. Prokaryotes have a region, called a nucleoid, in which their genetic material is concen- trated. However, prokaryotes lack an internal membrane system. Plant Cells Versus Animal Cells Three unique features distinguish plant cells from animal cells. One is the production of a cell wall by plant cells. Plant cells contain a large central vacuole. Third, plant cells contain a variety of plastids, which are not found in animal cells. Cell walls, central vacuoles, and plastids are unique features that are important to plant function. 1. Identify three unique features of plant cells. 2. List the differences between the plasma mem- brane, the primary cell wall, and the secondary cell wall. 3. Identify three functions of plastids. 4. Name three things that may be stored in vacuoles. 5. Describe the features that distinguish prokary- otes from eukaryotes and plant cells from animal cells. CRITICAL THINKING

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