Anti-Hypertensive Drugs PDF

ANTIHYPERTENSIVE DRUGS Lectured By: Roger Carlo P. Pineda, RN, MD Slides Provided For By: Regie De Jesus, RN, PhDNS Nursing Lecture Review of Blood Pressure Four variables influence blood flow and blood pressure: 1. Cardiac output 2. Compliance 3. Volume of the blood 4....

ANTIHYPERTENSIVE DRUGS Lectured By: Roger Carlo P. Pineda, RN, MD Slides Provided For By: Regie De Jesus, RN, PhDNS Nursing Lecture Review of Blood Pressure Four variables influence blood flow and blood pressure: 1. Cardiac output 2. Compliance 3. Volume of the blood 4. Resistance Review of Blood Pressure Cardiac output is the measurement of blood flow from the heart through the ventricles, and is usually measured in liters per minute. Any factor that causes cardiac output to increase, by elevating heart rate or stroke volume or both, will elevate blood pressure and promote blood flow. Review of Blood Pressure Cardiac output is INCREASED by: Sympathetic stimulation Thyroid hormones Increased calcium ion levels Cardiac output is DECREASED by: Parasympathetic stimulation Elevated or decreased potassium ion levels Decreased calcium levels Anoxia Acidosis. Review of Blood Pressure Compliance is the ability of any compartment to expand to accommodate increased content. A metal pipe, for example, is not compliant, whereas a balloon is. The greater the compliance of an artery, the more effectively it is able to expand to accommodate surges in blood flow without increased resistance or blood pressure. Review of Blood Pressure Blood Volume The relationship between blood volume, blood pressure, and blood flow is intuitively obvious. Water may merely trickle along a creek bed in a dry season, but rush quickly and under great pressure after a heavy rain. Similarly, as blood volume decreases, pressure and flow decrease. As blood volume increases, pressure and flow increase. Review of Blood Pressure Resistance: Blood viscosity is the thickness of fluids that affects their ability to flow. The viscosity of blood is directly proportional to resistance and inversely proportional to flow; therefore, any condition that causes viscosity to increase will also increase resistance and decrease flow. Review of Blood Pressure Resistance: Blood vessel length is directly proportional to its resistance: the longer the vessel, the greater the resistance and the lower the flow. Review of Blood Pressure Resistance: In contrast to length, the blood vessel diameter changes throughout the body, according to the type of vessel. The vascular tone of the vessel is the contractile state of the smooth muscle and the primary determinant of diameter, and thus of resistance and flow. The effect of vessel diameter on resistance is inverse: Given the same volume of blood, an increased diameter means there is less blood contacting the vessel wall, thus lower friction and lower resistance, subsequently increasing flow. A. Baroceptors (Pressure Receptors) specialized cells in the arch of the aorta and other tissues sensory input from the baroreceptors is received in the medulla in an area called the vasomotor center. If the pressure is high, the medulla stimulates vasodilation and a decrease in cardiac rate and output A. Baroceptors (Pressure Receptors) B. Renin–Angiotensin–Aldosterone System (RAAS) Types of Hypertension 1. Essential Hypertension (Primary Hypertension) Ninety percent of these cases have no known cause There is elevated total peripheral resistance The organs are perfused effectively and people with essential hypertension usually exhibit no symptoms (“Silent Killer”) Types of Hypertension 2. Secondary Hypertension characterized by elevated blood pressure due to a known cause For example, a tumor in the adrenal medulla called phaeochromocytoma can cause the organ to release a high amount of catecholamines, which greatly increase blood pressure. ANTIHYPERTENSIVE DRUGS Angiotensin-converting enzymes inhibitors (ACE Inhibitors) Angiotensin II-Receptor Blockers (ARBs) Renin Inhibitors Calcium-Channel Blockers Vasodilators Diuretic Agents Sympathetic Nervous System Blockers A. Angiotensin-converting enzymes inhibitors (ACE Inhibitors) are antihypertensive agents that act in the lungs to prevent the conversion of angiotensin I into angiotensin II, which is a potent vasoconstrictor. blood pressure is decreased with resultant loss of serum sodium and fluid but with a slight increase in serum potassium. A. Angiotensin-converting enzymes inhibitors (ACE Inhibitors) A. Angiotensin-converting enzymes inhibitors (ACE Inhibitors) A. Angiotensin-converting enzymes inhibitors (ACE Inhibitors) Examples of Generic Classification Names (suffix “pril”) Angiotensin- benazepril fosinopril converting captopril ramipril enzymes enalapril perindopril inhibitors (ACE Inhibitors) quinapril lisinopril A. Angiotensin-converting enzymes inhibitors (ACE Inhibitors) Indications Primarily indicated for hypertension and can be used alone or in combination with other drugs. It is also approved for treatment of diabetic nephropathy, in which the renal artery is being damaged by diabetes. Adults: ACE inhibitors are not allowed during pregnancy. Older adults: Renal and hepatic function should always be monitored. A. Angiotensin-converting enzymes inhibitors (ACE Inhibitors) Adverse Effects GI: irritations, ulcer, constipation, liver injury GU: renal insufficiency, renal failure, proteinuria CV: reflex tachycardia, chest pain, heart failure, cardiac arrhythmias (from HYPERKALEMIA) EENT: rash, alopecia, dermatitis, photosensitivity Captopril is associated with sometimes-fatal pancytopenia, cough, and GI distress. A. Angiotensin-converting enzymes inhibitors (ACE Inhibitors) NURSING CONSIDERATIONS Educate patient on importance of healthy lifestyle choices Administer drug on empty stomach one hour before or two hours after meal Monitor for presence of manifestations that signal decreased in fluid volume (Hypotensive effects) B. Angiotensin II-Receptor Blockers (ARBs) ARBs are antihypertensive agents that exert their action by blocking vasoconstriction and release of aldosterone through selective blocking of angiotensin II receptors in vascular smooth muscles and adrenal cortex. B. Angiotensin II-Receptor Blockers (ARBs) B. Angiotensin II-Receptor Blockers (ARBs) B. Angiotensin II-Receptor Blockers (ARBs) Examples of Generic Names (suffix Classification “sartan”) Angiotensin II- azilsartan irbesartan telmisartan Receptor Blockers (ARBs) candesartan losartan valsartan eprosartan olmesartan B. Angiotensin II-Receptor Blockers (ARBs) Indications used alone for treatment of hypertension or in combination Utilized in treatment of heart failure for patients who do not respond to ACE inhibitors. By blocking the effects of angiotensin receptors in vascular endothelium, these drugs are able to slow down the progress of renal disease in patients with type 2 diabetes and hypertension. Adults: ARBs are not allowed during pregnancy. Older adults: Renal and hepatic function should always be monitored. B. Angiotensin II-Receptor Blockers (ARBs) Adverse Effects CNS: headache, dizziness, syncope, weakness Respiratory: symptoms of upper respiratory tract infections (URTI), cough GI: diarrhea, abdominal pain, nausea, dry mouth, tooth pain EENT: rash, alopecia, dry skin B. Angiotensin II-Receptor Blockers (ARBs) NURSING CONSIDERATIONS Educate patient on importance of healthy lifestyle choices Administer drug with food to prevent GI distress Monitor for presence of manifestations that signal decreased in fluid volume (Hypotensive effects) Provide comfort measures (e.g. quiet environment, relaxation techniques, etc.) to help patient tolerate drug effects. C. Renin Inhibitors A new drug, released in 2007, Aliskiren (Tekturna) directly inhibits renin and inhibiting the conversion of angiotensinogen to angiotensin I. This inhibition of the renin–angiotensin– aldosterone system leads to decreased blood pressure, decreased aldosterone release, and decreased sodium reabsorption C. Renin Inhibitors D. Calcium-Channel Blockers inhibit the movement of calcium ions across myocardial and arterial muscle cell membranes. As a result, action potential of these cells are altered and cell contractions are blocked. Resultant effects include: depressed myocardial contractility, slow cardiac impulse in conductive tissues, and arterial dilation and relaxation. Since these drugs can significantly decrease cardiac workload, they are effective in treatment of angina. D. Calcium-Channel Blockers D. Calcium-Channel Blockers D. Calcium-Channel Blockers Indications used alone for treatment of hypertension or in combination Extended-release preparations are usually indicated for hypertensions in adults. Children: calcium-channel blockers are the drug group that is first considered in cases of hypertension Adults: these drugs are not allowed during pregnancy. Older adults: Renal and hepatic function should always be monitored. D. Calcium-Channel Blockers Adverse reactions CNS: headache, dizziness, light- headedness, fatigue CV: hypotension, bradycardia, peripheral edema, heart block GI: nausea, hepatic injury EENT: rash, skin flushing D. Calcium-Channel Blockers Classification Examples of Generic Names Dihydropyridines (suffix Non- Calcium- “dipine) Dihydropyridines Channel Amlodipine Nifedipine Diltiazem Blockers Felodipine Nicardipine Verapamil D. Calcium-Channel Blockers D. Calcium-Channel Blockers NURSING CONSIDERATIONS Educate patient on importance of healthy lifestyle choices Monitor blood pressure and heart rate and rhythm Provide comfort measures for the patient to tolerate side effects e.g. small frequent meals for nausea, limiting noise and controlling room light and temperature to prevent aggravation of stress which can increase demand to the heart, E. VASODILATORS exert their effect by acting directly on smooth muscles. Consequently, there will be muscle relaxation and vasodilation. Both of these will cause drop in blood pressure. They are reserved for severe hypertension and hypertensive emergencies E. VASODILATORS E. VASODILATORS Classification Examples of Generic Names hydralazine Vasodilators minoxidil nitropruisside E. VASODILATORS Indications only used for hypertension cases that do not respond to other drug therapies. Nitroprusside is used in maintaining controlled hypotension during surgery. Nitroprusside is administered intravenously; hydralazine is available for oral, intravenous, and intramuscular use; and minoxidil is available for oral use only. E. VASODILATORS Adverse Effects CNS: headache, dizziness, anxiety GI: nausea, vomiting, GI upset EENT: rash, lesions (e.g. minoxidil is associated with abnormal hair growth.) Nitroprusside is metabolized into cyanide so it can cause cyanide toxicity characterized by dyspnea, ataxia, loss of consciousness, distant heart sounds, and dilated pupil. Nitroprusside suppresses iodine uptake which leads to development of hypothyroidism. E. VASODILATORS NURSING CONSIDERATIONS Educate patient on importance of healthy lifestyle choices Monitor blood pressure and heart rate and rhythm Provide comfort measures for the patient to tolerate side effects e.g. small frequent meals for nausea, limiting noise and controlling room light and temperature to prevent aggravation of stress which can increase demand to the heart, E. VASODILATORS NURSING CONSIDERATIONS Monitor for presence of manifestations that signal decreased in fluid volume (Hypotensive effects) Monitor blood pressure and heart rate and rhythm Emphasize to the client the importance of strict adherence to drug therapy F. Diuretic Agents drugs that increase the excretion of sodium and water from the kidney often the first agents tried in mild hypertension (i.e. Thiazide & Loop) also use to manage edema (excessive accumulation of fluids) and glaucoma (an eye disease that is characterized by increased intraocular pressure (IOP) F. Diuretic Agents F. Diuretic Agents Five Classes of Diuretics 1. Thiazide Diuretics 2. Loop Diuretics 3. Carbonic Anhydrase Inhibitors Diuretics 4. Potassium Sparing Diuretics 5. Osmotic Diuretics 1. Thiazide Diuretics It causes active pumping out of chloride from the cells lining the ascending limb of Loop of Henle and distal tubule by blocking the chloride pump. Since sodium passively moves with chloride to maintain electrical neutrality, both sodium and chloride are excreted in the urine. Thiazide Diuretics This is among the most commonly used class of diuretics. Considered to be a milder form of diuretics compared to loop diuretics. First-line drugs for management of essential hypertension Thiazide Diuretics Classificatio Examples of Generic Names (suffix n “thiazide”) endroflumethiazide hydroflumethiazide Thiazide Diuretics chlorothiazide methyclothiazide hydrochlorothiazide Thiazide Diuretics Adverse Effects CNS: weakness CV: hypotension, arrhythmias GI: GI upset GU:hypokalemia (can precipitate hyperglycemia), hypercalcemia, hyperuremia, slightly-alkalinized urine (can lead to bladder infections) Potassium-Wasting Diuretics 2. Loop Diuretics Referred to as high-ceiling diuretics because they are capable of causing greater degree of diuresis Blocks the action of chloride pump in the ascending limb of the loop of Henle, where 30% of sodium is normally reabsorbed. Exerts the same effect on the descending limb of loop of Henle and distal tubule causing sodium-rich urine. 2. Loop Diuretics Classification Examples of Generic Names furosemide ethacrynic acid Thiazide torsemide bumetanide Diuretics 2. Loop Diuretics Indications treatment of acute HF, acute pulmonary edema, and edema associated with HF or with renal or liver disease, and hypertension. Drug of choice when rapid and extensive diuresis is needed. It can produce a fluid loss up to 20 pounds per day. 2. Loop Diuretics Adverse Effects CNS: dizziness; CV: hypotension GI: GI upset GU: hypokalemia (can precipitate hyperglycemia), increased bicarbonate excretion, hypocalcemia and tetany EENT: ototoxicity, reversible loss of hearing Potassium-Wasting Diuretics 3. Carbonic Anhydrase Inhibitors Diuretics Relatively mild diuretics which affects the proximal convoluted tubule Inhibits the action of the enzyme carbonic anhydrase, the catalyst for the formation of sodium bicarbonate stored as alkaline reserve in the renal tubules and is important for the excretion of hydrogen. It slows down the movement of hydrogen ions which leads to greater amount of sodium and bicarbonate lost in the urine. 3. Carbonic Anhydrase Inhibitors Diuretics Examples of Generic Classification Names Carbonic Anhydrase methazolamide Inhibitors Diuretics acetazolamide 3. Carbonic Anhydrase Inhibitors Diuretics Indications often used for the treatment of glaucoma. Inhibition of carbonic anhydrase results in decreased secretion of aqueous humor of the eyes. Also used as adjunct to other diuretics when more intense diuresis is needed. 3. Carbonic Anhydrase Inhibitors Diuretics Adverse Effects CNS: paresthesia, confusion, drowsiness CV: hypotension GU: hypokalemia (can precipitate hyperglycemia), increased loss of bicarbonate (can lead to metabolic acidosis) 4. Potassium-Sparing Diuretics Less powerful than loop diuretics but they retain potassium instead of wasting it. used for patients who have high risk for hypokalemia associated with diuretic use. 4. Potassium-Sparing Diuretics Classification Examples of Generic Names spironolactone Potassium-Sparing Diuretics triamterene amiloride Spironolactone acts as aldosterone antagonist which blocks the action of aldosterone in the distal tubule. Amiloride and triamterene block potassium secretion through the tubule. 4. Potassium-Sparing Diuretics Indications used as adjuncts with thiazide or loop diuretics or in patients who are especially at risk if hypokalemia develops. Spironolactone is the drug of choice for treating hyperaldosteronism typically seen in patients with liver cirrhosis and nephrotic syndrome. 4. Potassium-Sparing Diuretics Adverse Effects CNS: lethargy, confusion, ataxia CV: arrhythmias Musculoskeletal: muscle cramps GU: hyperkalemia, increased loss of bicarbonate (can lead to metabolic acidosis) Associated with various androgen effects such as hirsutism, gynecomastia, deepening of the voice, and irregular menses. 4. Potassium-Sparing Diuretics 5. Osmotic Diuretics exerts their therapeutic effect by pulling water into the renal tubule without loss of sodium. Only one osmotic diuretic is currently available, mannitol (Osmitrol). Mannitol is a sugar that is not well reabsorbed by the tubules and it acts to pull large amounts of fluid into the urine. This also pulls fluid into the vascular system from extravascular spaces like aqueous humor. 5. Osmotic Diuretics Indications used to decrease IOP before eye surgery or during acute attacks of glaucoma Diuretic of choice in cases of increased cranial pressure (e.g. Stroke) or acute renal failure Most common and potentially dangerous adverse effect related to an osmotic diuretic is the sudden drop in fluid levels. Nursing Considerations in the Use of Diuretics Administer intravenous diuretics slowly to prevent severe changes in fluid and electrolytes. Administer oral form early in the day to prevent increased urination during sleep hours. Monitor patient response to drugs through vital signs, weight, serum electrolytes and hydration to evaluate effectiveness of drug therapy Nursing Considerations in the Use of Diuretics Assess skin condition to determine presence of fluid volume deficit or retention. Provide safety measures (e.g. adequate lighting, raised side rails, etc.) to prevent injuries. Educate client on drug therapy to promote compliance. ANTIHYPERTENSIVE DRUGS Part 2 Lectured By: Roger Carlo P. Pineda, RN, MD Slides Provided For By: Regie De Jesus, RN, PhDNS Nursing Lecture G. Sympathetic Nervous System Blockers are useful in blocking many of the compensatory effects of the sympathetic nervous system Beta-blockers Alpha-1 Blockers (Alpha-1 Adrenergic Blockers) Alpha- Blockers (Alpha-2 Adrenergic Blockers) Centrally Acting Adrenergic Drugs (i.e. Alpha2- agonists) BETA-BLOCKERS Selective Beta-blockers - blocks beta-1 receptors in the heart thereby causing decrease in cardiac output resulting to decrease in blood pressure Non-Selective Beta-blockers - blocks beta-1 receptors in the heart (decrease in cardiac output) and kidneys (decrease renin and angiotensin II, and aldosterone) while simultaneously blocking alpha-1 receptors that decreases systemic vascular resistance resulting to decrease in blood pressure BETA-BLOCKERS BETA-BLOCKERS BETA-BLOCKERS Examples of Generic Names (suffix “olol”) atenolol (selective) Metoprolol (selective) Beta-Blockers betaxolol (Beta- nebivolol Adrenergic labetalol (non-selective) Antagonist) carvedilol(non-selective) propranolol timolol BETA-BLOCKERS Indications Nadolol is used for management of chronic angina. It is the drug of choice in angina patients with hypertension. Propranolol is the prototype drug of this class. It is used for treatment of angina and syncope. Nebivolol, the newest adrenergic blocking agent does not produce the same adverse effects seen in propranolol. BETA-BLOCKERS Caution: 4Bs Bradycardia (60 or less) Bottomed out BP (80/60) Breathing patterns (COPD, Asthma) Blood sugar masking (diabetics) BETA-BLOCKERS NURSING CONSIDERATIONS Provide comfort measures: ambulation assistance, raised siderails, appropriate room light and temperature, and rest periods (for fatigue and dizziness) Monitor cardiopulmonary status closely to detect possible alterations in vital signs which signal need for dose adjustment and to prevent related adverse effects. (for cough, dyspnea and arrhythmia) Educate client about the need to not abruptly stop therapy as this can lead to rebound hypertension and myocardial infarction. Alpha-1 Blockers (Alpha-1 Adrenergic Blockers) “ending in –osin” used to treat hypertension because of their ability to block the postsynaptic alpha1-receptor sites. This decreases vascular tone and promotes vasodilation, leading to a fall in blood pressure. Non-Selective Alpha- Blockers (Alpha 1 and 2 Adrenergic Blockers) these drugs also block presynaptic alpha2-receptors (located in pre- synaptic endings), preventing the feedback control of norepinephrine release. = MORE EPINEPHRINE The result (B1 stimulation) is an increase in the reflex tachycardia that occurs when blood pressure decreases. Alpha- Blockers (Alpha 1 and 2 Adrenergic Blockers) used to diagnose and manage episodes of pheochromocytoma, but they have limited usefulness in essential hypertension include the following agents: phenoxybenzamine (Dibenzyline) phentolamine (Regitine – the drug of choice for pheochromocytoma) Alpha- Blockers (Alpha-1 and 2 Adrenergic Blockers) used to diagnose and manage episodes of pheochromocytoma, but they have limited usefulness in essential hypertension include the following agents: phenoxybenzamine (Dibenzyline) phentolamine (Regitine – the drug of choice for pheochromocytoma) Centrally Acting Adrenergic Drugs (i.e. Alpha2-agonists) stimulate the alpha2- receptors in the CNS and inhibit the cardiovascular centers, leading to a decrease in sympathetic outflow from the CNS and a resultant drop in blood pressure. associated with many adverse CNS and GI effects, as well as cardiac dysrhythmias. Centrally Acting Adrenergic Drugs (i.e. Alpha2-agonists) include the following agents: clonidine (Catapres), guanfacine (Tenex), and methyldopa (generic). THANK YOU VERY MUCH!