Pharmacology Module 5 - Diuretics and Antihypertensives | PDF

NUR2474 PHARMACOLOGY MODULE 5 – CARDIOVASCULAR AND RENAL MEDICATIONS Prof. Anne Udechukwu Rasmussen University  Introduction to Diuretics  How diuretics work: Mechanism of action  Blockade of sodium and chloride reabsorption  Inhibit reabsorption of...

NUR2474 PHARMACOLOGY MODULE 5 – CARDIOVASCULAR AND RENAL MEDICATIONS Prof. Anne Udechukwu Rasmussen University  Introduction to Diuretics  How diuretics work: Mechanism of action  Blockade of sodium and chloride reabsorption  Inhibit reabsorption of sodium and chloride preventing water reabsorption  Site of action  Proximal tubule produces greatest diuresis  Adverse effects  Hypovolemia  Acid-base imbalance  Electrolyte imbalances 2 3  Introduction to Diuretics (Cont.)  Classification of diuretics  Four major categories Loop: Furosemide Thiazide: Hydrochlorothiazide Osmotic: Mannitol Potassium-sparing: Two subcategories  Aldosterone antagonists (spironolactone)  Nonaldosterone antagonists (triamterene)  Fifth group  Carbonic anhydrase inhibitors 4  Loop Diuretics  Furosemide (Lasix): Most frequently prescribed loop diuretic  Mechanism of action Acts on ascending loop of Henle to block reabsorption Inhibit reabsorption of sodium and chloride preventing water reabsorption Eliminates excess fluid = reduce pulmonary edema  Pharmacokinetics Rapid onset (PO 60 minutes; IV 5 minutes)  Therapeutic uses Pulmonary edema Edematous states Hypertension 5  Furosemide [Lasix]  Adverse effects  Hyponatremia, hypochloremia, and dehydration  Hypotension Loss of volume Relaxation of venous smooth muscle  Hypokalemia  Ototoxicity 6  Furosemide [Lasix] (Cont.)  Hyperglycemia  Hyperuricemia  Use in pregnancy If benefit outweighs the risk Monitor electrolytes, hematocrit, and fetal growth  Impact on lipids, calcium, and magnesium 7  Furosemide [Lasix] (Cont.)  Drug interactions  Digoxin  Ototoxic drugs  Potassium-sparing diuretics  Lithium  Antihypertensive agents  Nonsteroidal anti-inflammatory drugs  Preparations, dosage, and administration  Oral  Parenteral 8 Other High-Ceiling (Loop) Diuretics  Ethacrynic acid [Edecrin]  Bumetanide [Bumex]  Torsemide [Demadex]  All can cause:  Ototoxicity, hypovolemia, hypotension, hypokalemia, hyperuricemia, hyperglycemia, and disruption of lipid metabolism 9 10  Thiazides and Related Diuretics  Effects similar to those of loop diuretics  Increase renal excretion of sodium, chloride, potassium, and water  Elevate levels of uric acid and glucose  Maximum diuresis is considerably lower than with loop diuretics  Not effective when urine flow is scant (unlike with loop diuretics) 11 12  Hydrochlorothiazide  Hydrochlorothiazide [HydroDIURIL]  Most widely used  Action: Early segment distal convoluted tubule  Peaks in 4 to 6 hours  Therapeutic uses Essential hypertension Edema Diabetes insipidus 13  Hydrochlorothiazide (Cont.)  Adverse effects  Hyponatremia, hypochloremia, and dehydration  Hypokalemia  Use in pregnancy and lactation  Hyperglycemia  Hyperuricemia  Impact on lipids, calcium, and magnesium 14  Hydrochlorothiazide (Cont.)  Drug interactions  Digoxin  Augments effects of hypertensive medications  Can reduce renal excretion of lithium (leading to accumulation)  NSAIDs may blunt diuretic effect  Can be combined with ototoxic agents without increased risk of hearing loss 15 Potassium-Sparing Diuretics  Useful responses  Modest increase in urine production  Substantial decrease in potassium excretion  Rarely used alone for therapy  Aldosterone antagonist  Spironolactone  Nonaldosterone antagonists  Triamterene  Amiloride 16  Spironolactone [Aldactone]  Mechanism of action  Blocks aldosterone in the distal nephron  Retention of potassium  Increased excretion of sodium 17  Spironolactone [Aldactone] (Cont.)  Therapeutic uses  Hypertension  Edematous states  Heart failure (decreases mortality in severe failure)  Primary hyperaldosteronism  Premenstrual syndrome  Polycystic ovary syndrome  Acne in young women 18  Spironolactone [Aldactone] (Cont.)  Adverse effects  Hyperkalemia  Benign and malignant tumors  Endocrine effects  Drug interactions  Thiazide and loop diuretics  Agents that raise potassium levels 19  Osmotic Diuretic  Mannitol [Osmitrol]  Promotes diuresis by creating osmotic force within lumen of the nephron  Pharmacokinetics Drug must be given parenterally  Therapeutic uses Prophylaxis of renal failure Reduction of intracranial pressure Reduction of intraocular pressure 20  Mannitol [Osmitrol]  Adverse effects  Edema  Headache  Nausea  Vomiting  Fluid and electrolyte imbalance 21  Case Study A patient who sustained a head injury is admitted to the critical care unit with increased intracranial pressure (ICP). The healthcare provider says that a diuretic will be used to lower the patient’s ICP. The nurse anticipates that which diuretic will be ordered, and why? 22  Case Study (Cont.) Mannitol IV has been ordered for the patient. When the IV solution of mannitol arrives from the pharmacy, the nurse notes crystals in the fluid. What is the most appropriate action by the nurse? 23  Case Study (Cont.) Are there any other steps the nurse should take regarding IV administration of mannitol? 24  Question 1 When providing discharge teaching for a patient who has been prescribed furosemide [Lasix], it is most important for the nurse to include which dietary items to prevent adverse effects of furosemide [Lasix] therapy? A. Oranges, spinach, and potatoes B. Baked fish, chicken, and cauliflower C. Tomato juice, skim milk, and cottage cheese D. Oatmeal, cabbage, and bran flakes 25  Question 2 A patient is prescribed spironolactone [Aldactone] for treatment of hypertension. Which foods should the nurse teach the patient to avoid? A. Baked fish B. Low-fat milk C. Salt substitutes D. Green beans 26  Question 3 The nurse cares for a patient who is prescribed oral bumetanide twice daily. It is most important for the nurse to take which action? A. Monitor the patient for signs and symptoms of hyperkalemia. B. Insert a urinary catheter and assess the hourly urine output. C. Weigh the patient before administering each dose. D. Schedule the medication to be given at 0800 and 1400. 27  Question 4 A patient with heart failure who takes furosemide [Lasix] is diagnosed with bacterial pneumonia. Which medication, if ordered by the physician, should the nurse question? A. Ciprofloxacin [Cipro] B. Gentamicin [Garamycin] C. Amoxicillin [Amoxcil] D. Erythromycin [E-Mycin] 28 29  Antidysrhythmic Drugs  Classification  Class I: Sodium channel blockers  Class II: Beta blockers  Class III: Potassium channel blockers  Class IV: Calcium channel blockers  Other: Adenosine, digoxin, and ibutilide  Most of the drugs used to treat dysrhythmias can also cause new dysrhythmias or worsen the existing ones. 30  Class IA Agents  Quinidine  Effects on the heart Blocks sodium channels Slows impulse conduction Delays repolarization Blocks vagal input to the heart  Effects on the ECG Widens the QRS complex Prolongs the QT interval  Therapeutic uses Used for supraventricular and ventricular dysrhythmias 31  Class IA Agents (Cont.)  Adverse effects Diarrhea Cinchonism Cardiotoxicity Arterial embolism Alpha-adrenergic blockade, resulting in hypotension Hypersensitivity reactions  Drug interactions Digoxin 32 Other Class IA Agents  Procainamide [Procanbid]  Similar to quinidine  Only weakly anticholinergic  Adverse effects: Symptoms of systemic lupus erythematosus  Disopyramide [Norpace]  Similar to quinidine  Prominent side effects have limited its use 33  Class IB Agents  Lidocaine [Xylocaine]  Effects on the heart and ECG Blocks cardiac sodium channels  Slows conduction in the atria, ventricles, and His-Purkinje system Reduces automaticity in the ventricles and His-Purkinje system Accelerates repolarization  Adverse effects CNS effects Drowsiness Confusion Paresthesias 34 Class IB Agents (Cont.)  Other class IB agents  Phenytoin Antiseizure medication also used to treat digoxin- induced dysrhythmias  Mexiletine Oral analog of lidocaine Used for symptomatic ventricular dysrhythmias 35 Class II: Beta Blockers  Beta-adrenergic blocking agents  Only four approved for treating dysrhythmias 1. Propranolol 2. Acebutolol 3. Esmolol 4. Sotalol 36  Class II: Beta Blockers (Cont.)  Propranolol [Inderal]: Nonselective beta-adrenergic antagonist  Effects on the heart and ECG Decreased automaticity of the SA node Decreased velocity of conduction through the AV node Decreased myocardial contractility  Therapeutic use Dysrhythmias caused by excessive sympathetic stimulation Supraventricular tachydysrhythmias  Suppression of excessive discharge  Slowing of ventricular rate 37 Class II: Beta Blockers (Cont.)  Propranolol [Inderal]: Nonselective beta-adrenergic antagonist  Effects on the heart and ECG Decreased automaticity of the SA node Decreased velocity of conduction through the AV node Decreased myocardial contractility  Therapeutic use Dysrhythmias caused by excessive sympathetic stimulation Supraventricular tachydysrhythmias  Suppression of excessive discharge  Slowing of ventricular rate 38  Class III: Potassium Channel Blockers  Amiodarone [Cordarone, Pacerone]  Therapeutic use For life-threatening ventricular dysrhythmias only Recurrent ventricular fibrillation Recurrent hemodynamically unstable ventricular tachycardia 39  Class III: Potassium Channel Blockers (Cont.)  Effects on the heart and ECG Reduced automaticity in the SA node Reduced contractility Reduced conduction velocity QRS widening Prolongation of the PR and QT intervals 40  Class III: Potassium Channel Blockers (Cont.)  Adverse effects Protracted half-life Pulmonary toxicity Cardiotoxicity Toxicity in pregnancy and breast-feeding Corneal microdeposits Optic neuropathy 41  Class III: Potassium Channel Blockers (Cont.)  Amiodarone levels can be increased by grapefruit juice and by inhibitors of CYP3A4. Toxicity can result.  Amiodarone levels can be reduced by cholestyramine (which decreases amiodarone absorption) and by agents that induce CYP3A4 (eg, St. John’s wort, rifampin). 42  Class III: Potassium Channel Blockers (Cont.)  The risk of severe dysrhythmias is increased by diuretics (because they can reduce levels of potassium and magnesium) and by drugs that prolong the QT interval, of which there are many  Combining amiodarone with a beta blocker, verapamil, or diltiazem can lead to excessive slowing of the heart rate 43  Class IV: Calcium Channel Blockers  Verapamil [Calan, Covera, Verelan] and diltiazem [Cardizem]  Reduce SA nodal automaticity  Delay AV nodal conduction  Reduce myocardial contractility  Therapeutic uses Slow ventricular rate (atrial fibrillation or atrial flutter) Terminate SVT caused by an AV nodal reentrant circuit 44  Class IV: Calcium Channel Blockers (Cont.)  Verapamil [Calan, Verelan] and diltiazem [Cardizem]  Adverse effects Hypotension AV block Heart failure Peripheral edema Constipation, dizziness, facial flushing, headache Can elevate digoxin levels  No grapefruit juice 45  Diltiazem [Cardizem, Dilacor-XR, Tiazac]  Actions and uses  Blocks calcium channels in the heart and blood vessels (similar to verapamil)  Lowers blood pressure Arteriolar dilation Direct suppressant/reflex cardiac stimulation = Little net effect on the heart 46  Diltiazem [Cardizem, Dilacor-XR, Tiazac] (Cont.)  Therapeutic uses  Angina pectoris  Hypertension  Cardiac dysrhythmias Atrial flutter, atrial fibrillation, paroxysmal tachycardia 47  Diltiazem [Cardizem, Dilacor-XR, Tiazac] (Cont.)  Adverse effects  Similar to verapamil, except for less constipation  Dizziness  Flushing  Headache  Edema of ankles and feet  Exacerbates bradycardia, sick sinus syndrome, heart failure, second- or third-degree heart block 48  Diltiazem [Cardizem, Dilacor-XR, Tiazac] (Cont.)  Drug interactions  Digoxin  Beta-adrenergic blocking agents 49 Nifedipine [Adalat CC, Nifedical, Procardia] (Cont.)  Vasodilation by blocking calcium channels  Net effect Lowered blood pressure Increased heart rate Increased contractile force 50 Nifedipine [Adalat CC, Nifedical, Procardia] (Cont.)  Therapeutic uses  Angina pectoris  Hypertension  Investigational basis: To relieve migraine headache and to suppress preterm labor 51 Nifedipine [Adalat CC, Nifedical, Procardia] (Cont.)  Adverse effects  Flushing  Dizziness  Headache  Peripheral edema  Gingival hyperplasia  Chronic eczematous rash in older patients 52  DIGOXIN  Digoxin [Lanoxin]  Primary indication is heart failure  Side effects: dysrhythmias, GI symptoms (n/v, anorexia), CNS symptoms (fatigue, visual disturbance)  Adverse effect: Cardiotoxicity Risk increased by hypokalemia  No grapefruit juice , no high sodium foods (potato chips) – fluid retention 53 Other Antidysrhythmic Drugs  Adenosine [Adenocard]  Effects on the heart and ECG Decreases automaticity in the SA node Slows conduction through the AV node Prolongs PR interval  Therapeutic use: Termination of paroxysmal SVT 54  Question 1 The nurse is preparing to administer adenosine [Adenocard] to a patient to treat paroxysmal supraventricular tachycardia (SVT). Which action by the nurse is most appropriate? A. Inject the medication into the peripheral intravenous (IV) line. B. Infuse the dose by diluting the drug in 100 mL of saline. C. Administer a small test dose to determine hypersensitivity. D. Give the medication through the central line catheter. 55  Question 2 The nurse administers an intravenous infusion of amiodarone [Coredarone] to a patient to prevent recurrent episodes of ventricular fibrillation. It is most important for the nurse to assess the patient for which condition? A. Urinary retention B. Hypercalcemia C. Hypotension D. Metallic taste 56  Question 3 A patient diagnosed with systemic lupus erythematosus (SLE) develops a dysrhythmia. Which medication, if ordered by the physician, should the nurse question? A. Lidocaine [Xylocaine] B. Procainamide [Procanbid] C. Disopyramide [Norpace] D. Amiodarone [Cordarone] 57  Question 4 A patient is to receive a scheduled dose of diltiazem [Cardizem]. The nurse should hold the medication and contact the prescriber if which of the following is noted? A. The patient’s blood pressure is 112/64 mm Hg. B. The patient’s cardiac rhythm is atrial fibrillation. C. The patient is complaining of chest pain. D. The patient is in second-degree heart block. 58  Question 5 The nurse instructs a patient about taking nifedipine [Procardia ]. Which statement made by the patient indicates an understanding of medication teaching? A. “I’ll stop taking my beta blocker.” B. “The pill should be swallowed whole.” C. “The drug will cause constipation.” D. “This drug treats heart rhythm problems.” 59  Question 6 A patient is prescribed verapamil [Calan SR ]. The nurse should assess the patient for which common adverse effects? A. Atrial fibrillation, photosensitivity, and blurred vision B. Tachycardia, stomatitis, and inflammation of the joints C. Constipation, headache, and edema of the ankles and feet D. Dry mouth, lymphadenopathy, and decreased appetite 60  Question 7 The healthcare provider prescribes sustained-release verapamil [Calan SR] to an 82-year-old patient who takes digoxin [Lanoxin] daily. Which action is most appropriate for the nurse to take? A. Monitor the patient’s cardiac rhythm continuously. B. Assess the patient for tachycardia and hypertension. C. Maintain the patient on bed rest for 8 to 10 hours. D. Reduce dietary fiber to prevent loose, watery diarrhea. 61  Drugs for Heart Failure  Diuretics  RAAS inhibitors  Angiotensin-converting enzyme inhibitors  Angiotensin II receptor blockers  Aldosterone antagonists  Direct renin inhibitors  Beta blockers  Digoxin  Dopamine  Hydralazine 62  Management of Heart Failure  Stage A  No symptoms of HF  No structural or functional cardiac abnormalities  Hypertension, coronary artery disease (CAD), diabetes, family history of cardiomyopathy, personal history of alcohol abuse, rheumatic fever, or treatment with a cardiotoxic drug (eg, doxorubicin, trastuzumab)  Management is directed at reducing the risk 63  Management of Heart Failure (Cont.)  Stage B  No signs or symptoms of HF  Goal of management is to prevent development of symptomatic HF  Treatment is the same as for stage A with the addition of ACE inhibitors or ARBs 64  Management of Heart Failure (Cont.)  Stage C  Symptoms of HF  Structural heart disease  Four major goals Relieve pulmonary and peripheral congestive symptoms Improve functional capacity and quality of life Slow cardiac remodeling and progression of LV dysfunction Prolong life 65  Management of Heart Failure (Cont.)  Drug therapy Diuretics ACE inhibitors and ARBs Aldosterone antagonists Beta blockers Digoxin Isosorbide dinitrate/hydralazine  Drugs to avoid Antidysrhythmic agents Calcium channel blockers NSAIDs, including aspirin 66  Management of Heart Failure (Cont.)  Device therapy Implanted cardioverter- defibrillators Cardiac resynchronization  Exercise training  Evaluating treatment Based on symptoms and physical findings 67  Management of Heart Failure (Cont.)  Stage D  Marked symptoms of HF  Advanced structural heart disease  Repeated hospitalizations  Best solution is a heart transplant LV mechanical assist device used until heart is available  Management Control of fluid retention  Loop diuretic, thiazide diuretic  Dopamine, dobutamine Beta blockers pose high risk of worsening HF 68  Question 1 A patient is prescribed digoxin [Lanoxin] and furosemide [Lasix]. It is most important for the nurse to assess which value before administering these medications? A. Serum sodium B. Blood urea nitrogen C. Serum potassium D. Plasma B-natriuretic peptide 69  Question 2 A nurse instructs a patient about signs and symptoms of digoxin toxicity. The nurse determines that teaching is successful if the patient makes which statement? A. “If my heart is racing, the dose may be too high.” B. “I should report any muscle weakness or nausea.” C. “My doctor should be notified if diarrhea occurs.” D. “The dose will be reduced if I develop memory loss.” 70  Question 3 The nurse cares for a patient receiving digoxin [Lanoxin]. What indicates to the nurse that treatment with this medication is effective? A. Improved cardiac output B. Reduced exercise tolerance C. Increased body weight D. Decreased cardiac contractility 71  Question 4 The nurse cares for a patient with a digoxin level of 1.9 ng/mL. Which action would be most appropriate for the nurse to take initially? A. Start continuous heart monitoring. B. Check the patient’s serum creatinine. C. Administer digoxin as prescribed. D. Give Fab antibody fragments [Digibind]. 72  Classification of Blood Pressure (BP)  Normal Systolic BP below 120 mm Hg and diastolic BP below 80 mm Hg  Elevated Systolic BP of 120 to 129 mm Hg and diastolic BP > 80 mm Hg  Hypertension Stage 1: Systolic BP above 130-139mm Hg or diastolic BP 80-89 mm Hg Stage 2: Systolic BP >140 mm Hg or diastolic BP > 90 mm Hg 73 Types of Hypertension  Two broad categories of hypertension  Primary (essential) hypertension No identifiable cause Chronic, progressive disorder Population: Older adults, African Americans, postmenopausal women Treated but not cured (lifelong condition) Referred to as essential hypertension  Secondary hypertension Identifiable primary cause Possible to treat the cause directly Some individuals can actually be cured 74 Risk of Hypertension  Untreated hypertension can lead to heart disease, kidney disease and stroke 75 76 77 78  Angiotensin-Converting Enzyme (ACE) Inhibitors (Cont.)  How it works:  Inhibit the enzyme that converts angiotensin I to angiotensin II  They can inhibit aldosterone release causing the kidneys to retain potassium 79  Angiotensin-Converting Enzyme (ACE) Inhibitors (Cont.)  Adverse effects  First-dose hypotension  Fetal injury  Cough  Angioedema ACE inhibitors can cause angioedema, a potentially life-threatening reaction. If patients report edema of the tongue, lips, or eyes, emergency care should be sought immediately. The patient must never take ACE inhibitors again. 80  Aldosterone Antagonists (Cont.)  Adverse effects Hyperkalemia Gynecomastia Menstrual irregularities Impotence Hirsutism Deepening of the voice 81  Angiotensin-Converting Enzyme (ACE) Inhibitors (Cont.)  Drug interactions  Diuretics  Antihypertensive agents  Drugs that raise potassium levels  Lithium  Nonsteroidal anti-inflammatory drugs 82 83 84  Question 1 A patient diagnosed with heart failure has stage 1 hypertension. Which medication, if ordered by the healthcare provider, should the nurse question? A. Angiotensin-converting enzyme inhibitor B. Calcium channel blocker C. Thiazide diuretic D. Beta blocker 85  Question 2 A patient with stage 2 hypertension has been prescribed a thiazide diuretic and an angiotensin-converting enzyme inhibitor. It is most appropriate for the nurse to do what? A. Contact the healthcare provider. B. Administer both drugs to the patient. C. Administer the thiazide diuretic at bedtime. D. Hold the medications if the blood pressure is normal. 86  Question 3 A patient has hypertension, type 2 diabetes, and chronic kidney disease. Which blood pressure goal would be most beneficial for this patient? A. Blood pressure less than 140/90 mm Hg B. Diastolic blood pressure less than 100 mm Hg C. Blood pressure less than 130/80 mm Hg D. Systolic blood pressure less than 160 mm Hg 87  Question 4 The nurse teaches a patient about benazepril [Lotensin]. Which statement by the patient requires an intervention by the nurse? A. “I use NoSalt instead of salt to season foods.” B. “I eat sweet potatoes once or twice a week.” C. “I drink 4 ounces of prune juice each morning.” D. “I like asparagus because it’s high in vitamin K.” 88