Antihypertensives- Chapter 22.pptx

Chapter 22 Antihypertensive Drugs  Hypertension Defined (JNC-8)  60 years or older: systolic blood pressure (SBP) of greater than 150 mm Hg or diastolic blood pressure (DBP) greater than 90 mm Hg  Younger than 60 years and those who have chronic kidney disease or diabetes:...

Chapter 22 Antihypertensive Drugs  Hypertension Defined (JNC-8)  60 years or older: systolic blood pressure (SBP) of greater than 150 mm Hg or diastolic blood pressure (DBP) greater than 90 mm Hg  Younger than 60 years and those who have chronic kidney disease or diabetes: SBP greater than 140 and DBP greater than 90 2  Blood Pressure  Blood pressure (BP) = CO × SVR  CO = cardiac output  SVR = systemic vascular resistance  Hypertension = high BP  Hypertension is currently one of the most common disease states.  Hypertension is major risk factor for coronary artery disease (CAD), cardiovascular disease (CVD). 3 Eighth Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC-8)* (Cont.)  According to the JNC 8, therapy should be started if BP is at or greater than150/90 for patients older than 60 years and 140/90 for patients younger than 60 and those who have chronic kidney disease or diabetes. *Released December 2013. 4  Classification of Blood Pressure  Hypertension can also be defined by its cause.  Unknown cause  Essential, idiopathic, or primary hypertension  90% of cases  Known cause  Secondary hypertension  10% of cases 5  Audience Response System Question #1 The number of people with hypertension in the United States is estimated to be A. 10 million. B. 25 million. C. 50 million. D. 75 million. NOTE: No input is required to proceed. 6  Answer to System Question # 1 ANS: D Hypertension affects approximately 75 million people in the United States and approximately 1 billion people worldwide, designating it as the most common disease state. 7  Pharmacology Overview  Drug therapy for hypertension must be individualized.  Seven main categories of drugs to treat hypertension  Diuretics  Adrenergic drugs  Vasodilators  Angiotensin-converting enzyme (ACE) inhibitors  Angiotensin II receptor blockers (ARBs)  Calcium channel blockers (CCBs)  Direct renin inhibitors 8  Review of Autonomic Neurotransmission  Two divisions of autonomic nervous system (ANS)  Parasympathetic nervous system (PNS): stimulates smooth muscles, cardiac muscles, glands  Sympathetic nervous system (SNS): stimulates heart, blood vessels, skeletal muscles  Stimulation is controlled by neurotransmitters.  Acetylcholine  Norepinephrine  Receptors located throughout the body 9 Adrenergic Drugs: Five Subcategories  Adrenergic neuron blockers (central and peripheral)  Alpha2 receptor agonists (central)  Alpha1 receptor blockers (peripheral)  Beta receptor blockers (peripheral)  Combination alpha1 and beta receptor blockers (peripheral) 10  Centrally Acting Adrenergic Drugs  Clonidine and methyldopa  Stimulate alpha2-adrenergic receptors in the brain  Decrease sympathetic outflow from the central nervous system  Decrease norepinephrine production  Stimulate alpha2-adrenergic receptors, thus reducing renin activity in the kidneys  Result in decreased BP 11 Peripherally Acting Alpha1 Blockers  Doxazosin, prazosin, and terazosin  Block alpha1-adrenergic receptors  When alpha1-adrenergic receptors are blocked, BP is decreased.  Dilate arteries and veins  Alpha1 blockers also increase urinary flow rates and decrease outflow obstruction by preventing smooth muscle contractions in the bladder neck and urethra.  Use: benign prostatic hyperplasia (BPH) 12  Beta Blockers  Propranolol, metoprolol, and atenolol  Reduction of the heart rate through beta1 receptor blockade  Cause reduced secretion of renin  Long-term use causes reduced peripheral vascular resistance. 13 Dual-Action Alpha1 and Beta Receptor Blockers  Labetalol and carvedilol  Dual antihypertensive effects of reduction in heart rate (beta1 receptor blockade) and vasodilation (alpha1 receptor blockade) 14  Adrenergic Drugs: Indications/Contraindications  All used to treat hypertension  Glaucoma  BPH: doxazosin, prazosin, and terazosin  Management of severe heart failure (HF) when used with cardiac glycosides and diuretics  Contraindications:  Acute HF  MOAIs  Peptic ulcers  Severe liver/kidney disease  Asthma (with beta blockers) 15  Adrenergic Drugs: Adverse Effects  High incidence of orthostatic hypotension  First-dose syncope  Most common  Bradycardia with reflex tachycardia  Dry mouth  Drowsiness, sedation  Constipation  Depression  Edema  Sexual dysfunction 16  Adrenergic Drugs: Adverse Effects (Cont.)  Other  Headaches  Sleep disturbances  Nausea  Rash  Rebound hypertension with abrupt discontinuation 17  Adrenergic Drugs: Interactions  Can cause additive CNS depression with alcohol, benzodiazepines, opioids  Always check for specific drug interactions 18  Audience Response System Question #2 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? A. Hypotension B. Hyperkalemia C. Oliguria D. Respiratory distress NOTE: No input is required to proceed. 19  Answer to System Question #2 ANS: A These drugs have strong vasodilating properties and may cause severe hypotension, especially at the beginning of therapy. 20  Alpha2-Adrenergic Receptor Stimulators (Agonists)  Clonidine and methyldopa  Not typically prescribed as first-line antihypertensive drugs  High incidence of unwanted adverse effects: orthostatic hypotension, fatigue, and dizziness  Adjunct drugs to treat hypertension after other drugs have failed.  Used in conjunction with other antihypertensives such as diuretics 21  Clonidine (Catapres)  Used primarily for its ability to decrease blood pressure  Also used for management of opioid withdrawal  Oral and topical patch  Do not stop abruptly  May lead to rebound hypertension 22  Alpha1 Blockers  Doxazosin (Cardura)  Prazosin (Minipress)  Tamsulosin (Flomax)*  Terazosin (Hytrin) *Tamsulosin is not used to control BP but is indicated solely for symptomatic control of BPH. 23  Doxazosin (Cardura)  Commonly used alpha1 blocker  Reduces peripheral vascular resistance and BP by dilating both arterial and venous blood vessels 24 Dual-Action Alpha1 and Beta Receptor Blockers  Carvedilol (Coreg)  Widely used drug that is well tolerated  Uses: hypertension, mild to moderate HF in conjunction with digoxin, diuretics, and ACE inhibitors  Contraindications: known drug allergy, cardiogenic shock, severe bradycardia or HF, bronchospastic conditions such as asthma, and various cardiac problems involving the conduction system 25  Beta Receptor Blocker  Nebivolol (Bystolic)  Uses: hypertension and HF  Action: blocks beta1 receptors and produces vasodilatation, which results in a decrease in SVR  Less sexual dysfunction  Do not stop abruptly; must be tapered over 1 to 2 weeks 26  Angiotensin-Converting Enzyme (ACE) Inhibitors  Large group of safe and effective drugs  Currently are 10 ACE inhibitors  Often used as first-line drugs for HF and hypertension  May be combined with a thiazide diuretic or CCB 27  Angiotensin-Converting Enzyme (ACE) Inhibitors (Cont.)  Captopril (Capoten)  Benazepril (Lotensin)  Enalapril (Vasotec)  Fosinopril (Monopril)  Lisinopril (Prinivil)  Perindopril (Aceon)  Quinapril (Accupril)  Ramipril (Altace)  Trandolapril (Mavik) 28  ACE Inhibitors: Mechanism of Action  Inhibit ACE  ACE: converts angiotensin I (AI) (formed through the action of renin) to angiotensin II (AII)  AII: potent vasoconstrictors that induce aldosterone secretion by the adrenal glands  Aldosterone: stimulates sodium and water resorption, which can raise BP  Renin-angiotensin-aldosterone system  ACE inhibitors thus lower BP. 29  Primary Effects of the ACE Inhibitors  Cardiovascular and renal  BP: reduce BP by decreasing SVR  HF  Prevent sodium and water resorption by inhibiting aldosterone secretion  Diuresis: decreases blood volume and return to the heart  Decreases preload, or the left ventricular end-diastolic volume  Decreases work required of the heart 30  Cardioprotective Effects of the ACE Inhibitors  ACE inhibitors decrease SVR (a measure of afterload) and preload.  Used to prevent complications after MI  Ventricular remodeling: left ventricular hypertrophy, which is sometimes seen after MI  ACE inhibitors have been shown to decrease morbidity and mortality in patients with HF.  Drugs of choice for hypertensive patients with HF 31  Renal Protective Effects of the ACE Inhibitors  ACE inhibitors: reduce glomerular filtration pressure  Cardiovascular drugs of choice for patients with diabetes  ACE inhibitors reduce proteinuria.  Standard therapy for diabetic patients to prevent the progression of diabetic nephropathy 32  ACE Inhibitors: Indications  Hypertension  HF (either alone or in combination with diuretics or other drugs)  Slow progression of left ventricular hypertrophy after myocardial infarction (MI) (cardioprotective)  Renal protective effects in patients with diabetes 33  Audience Response System Question #4 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? A. Clonidine B. Prazosin C. Diltiazem D. Captopril NOTE: No input is required to proceed. 34  Answer to System Question #4 ANS: D 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. 35  ACE Inhibitors: Adverse Effects  Fatigue  Dizziness  Headache  Mood changes  Impaired taste  Possible hyperkalemia  Dry, nonproductive cough, which reverses when therapy is stopped  Angioedema: rare but potentially fatal NOTE: First-dose hypotensive effect may occur. 36  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 37  Enalapril (Vasotec)  Only ACE inhibitor available in both oral and parenteral preparations  Enalapril intravenous (IV) does not require cardiac monitoring.  Oral enalapril: prodrug  Improves patient’s chances of survival after an MI  Reduces the incidence of HF 38  Angiotensin II Receptor Blockers  Also referred to as angiotensin II blockers  Well tolerated  Do not cause a dry cough that is common with ACE inhibitors 39 Angiotensin II Receptor Blockers (Cont.)  Losartan (Cozaar)  Eprosartan (Teveten)  Valsartan (Diovan)  Irbesartan (Avapro)  Candesartan (Atacand)  Olmesartan (Benicar)  Telmisartan (Micardis)  Azilsartan (Edarbi) 40  Angiotensin II Receptor Blockers: Mechanism of Action  ARBs affect primarily vascular smooth muscle and the adrenal gland.  Selectively block the binding of AII to the type 1 AII receptors in these tissues  ARBs block vasoconstriction and the secretion of aldosterone. 41  Comparison of ACE Inhibitors and Angiotensin II Receptor Blockers  ACE inhibitors and ARBs appear to be equally effective for the treatment of hypertension.  Both are well tolerated.  ARBs do not cause cough.  Evidence that ARBs are better tolerated and are associated with lower mortality after MI than ACE inhibitors  Not yet clear whether ARBs are as effective as ACE inhibitors in treating HF (cardioprotective effects) or in protecting the kidneys, as in diabetes 42  Angiotensin II Receptor Blockers: Indications  Hypertension  Adjunctive drugs for the treatment of HF  May be used alone or with other drugs such as diuretics 43  Angiotensin II Receptor Blockers: Adverse Effects  Most common adverse effects of ARBs  Chest pain  Fatigue  Hypoglycemia  Diarrhea  Urinary tract infection  Anemia  Weakness  Hyperkalemia and cough are less likely to occur than with the ACE inhibitors. 44  Audience Response System Question #5 Which statement about ARBs does the nurse identify as being true? A. Hyperkalemia is more likely to occur than when using ACE inhibitors. B. Cough is more likely to occur than when using ACE inhibitors. C. Chest pain is a common adverse effect. D. Overdose is usually manifested by hypertension and bradycardia. NOTE: No input is required to proceed. 45  Answer to System Question #5 ANS: C The most common adverse effects of ARBs are chest pain, fatigue, hypoglycemia, diarrhea, urinary tract infection, anemia, and weakness. Hyperkalemia and cough are less likely to occur than with the ACE inhibitors. Overdose may manifest as hypotension and tachycardia; bradycardia occurs less often. Treatment is symptomatic and supportive and includes the administration of IV fluids to expand the blood volume. 46  Losartan (Cozaar)  Beneficial in patients with hypertension and HF  Used with caution in patients with renal or hepatic dysfunction and in patients with renal artery stenosis  Not safe for breastfeeding women and should not be used in pregnancy 47  Calcium Channel Blockers: Mechanism of Action  Primary use: HTN and angina  Cause smooth muscle relaxation by blocking the binding of calcium to its receptors, preventing muscle contraction  Results in:  Decreased peripheral smooth muscle tone  Decreased SVR  Decreased BP 48  Calcium Channel Blockers: Indications  Angina  Hypertension: amlodipine (Norvasc)  Dysrhythmias  Migraine headaches  Raynaud’s disease  Prevent the cerebral artery spasms after subarachnoid hemorrhage: nimodipine 49  Diuretics  First-line antihypertensives in the JNC 8 guidelines for the treatment of hypertension  Decrease plasma and extracellular fluid volumes  Results  Decreased preload  Decreased CO  Decreased total peripheral resistance  Overall effect  Decreased workload of the heart and decreased BP  Thiazide diuretics are the most commonly used diuretics for hypertension. 50  Vasodilators  Diazoxide (Hyperstat)  Hydralazine (Apresoline)  Minoxidil (Rogaine)  For hair regrowth  Nitroprusside (Nitropress) 51  Vasodilators: Mechanism of Action  Directly relax arteriolar or venous smooth muscle (or both)  Results in:  Decreased SVR  Decreased afterload  Peripheral vasodilation 52  Vasodilators: Indications  Treatment of hypertension  May be used in combination with other drugs  Sodium nitroprusside and IV diazoxide are reserved for the management of hypertensive emergencies. 53  Vasodilators: Adverse Effects  Hydralazine: dizziness, headache, anxiety, tachycardia, edema, dyspnea, nausea, vomiting, diarrhea, hepatitis, systemic lupus erythematosus, vitamin B6 deficiency, and rash  Minoxidil: T-wave electrocardiographic changes, pericardial effusion or tamponade, angina, breast tenderness, rash, and thrombocytopenia 54  Vasodilators: Adverse Effects (Cont.)  Sodium nitroprusside: bradycardia, decreased platelet aggregation, rash, hypothyroidism, hypotension, methemoglobinemia, and (rarely) cyanide toxicity 55 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 56  Vasodilators: Sodium Nitroprusside (Nitropress)  Used in the intensive care setting for severe hypertensive emergencies; titrated to effect by IV infusion  Contraindications: known hypersensitivity to the drug, severe HF, and known inadequate cerebral perfusion (especially during neurosurgical procedures) 57  Sildenafil and Tadalafil  Commonly used for erectile dysfunction  Also used for pulmonary hypertension but with different trade names  Sildenafil: Revatio  Tadalafil: Adcirca 58  Nursing Implications  Before beginning therapy, obtain a thorough health history and head-to-toe physical examination.  Assess for contraindications to specific antihypertensive drugs.  Assess for conditions that require cautious use of these drugs. 59  Nursing Implications (Cont.)  Educate patients about the importance of not missing a dose and taking the medications exactly as prescribed.  Instruct patients to check with their physicians for instructions on what to do if a dose is missed; patients should never double up on doses if a dose is missed.  Monitor BP during therapy; instruct patients to keep a journal of regular BP checks. 60  Nursing Implications (Cont.)  Instruct patients that these drugs should not be stopped abruptly because this may cause a rebound hypertensive crisis and perhaps lead to stroke.  Oral forms should be given with meals so that absorption is more gradual and effective.  Administer IV forms with extreme caution and use an IV pump. 61  Nursing Implications (Cont.)  Remind patients that medication is only part of therapy. Encourage patients to watch their diet, stress level, weight, and alcohol intake.  Instruct patients to avoid smoking and eating foods high in sodium.  Encourage supervised exercise. 62  Nursing Implications (Cont.)  Teach patients to change positions slowly to avoid syncope from postural hypotension.  Instruct patients to report unusual shortness of breath; difficulty breathing; swelling of the feet, ankles, face, or around the eyes; weight gain or loss; chest pain; palpitations; and excessive fatigue. 63  Nursing Implications (Cont.)  Male patients who take these drugs may not be aware that impotence is an expected effect, and this may influence compliance with drug therapy.  If patients are experiencing serious adverse effects or if they believe the dose or medication needs to be changed, they should contact their physicians immediately. 64  Nursing Implications (Cont.)  Hot tubs, showers, or baths; hot weather; prolonged sitting or standing; physical exercise; and alcohol ingestion may aggravate low BP, leading to fainting and injury; patients should sit or lie down until symptoms subside.  Patients should not take any other medications, including over-the-counter drugs, without first getting the approval of their physicians. 65  Nursing Implications (Cont.)  Educate patients about lifestyle changes that may be needed.  Weight loss  Stress management  Supervised exercise  Dietary measures 66  Nursing Implications (Cont.)  Monitor for adverse effects (dizziness, orthostatic hypotension, fatigue) and for toxic effects.  Monitor for therapeutic effects. 67  ACE Inhibitors and Laboratory Values  ACE inhibitors can cause renal impairment, which can be identified with serum creatinine.  ACE inhibitors can also cause hyperkalemia, so potassium levels need to be monitored. 68