DRUGS ACTING ON THE
CARDIOVASCULAR SYSTEM
ANTIHYPERTENSIVE AGENTS
**for High blood pressure
•Normal: Systolic < 130 mm Hg Diastolic < 85 mm Hg
Classification of Blood Pressure
Category Systemic BP (mm Hg) Diastolic BP (mm Hg)
Normal <130 <85
High normal 130-139 85-89
Hypertension
Stage 1 140-159 90-99
Stage 2 160-169 100-109
Stage 3 180-209 110-119
Stage 4 > 210 > 120
Classification of Blood Pressure
Primary Hypertension
•Specific cause unknown
•90% of the cases
•Also known as essential or idiopathic hypertension
Secondary Hypertension
•Cause is known (such as eclampsia of pregnancy, renal artery disease, pheochromocytoma)
•10% of the cases
Blood Pressure = CO x SVR
•CO = Cardiac output
•SVR = Systemic vascular resistance
Antihypertensive Agents
•Adrenergic agents
•Angiotensin-converting enzyme inhibitors
•Angiotensin II receptor blockers
•Calcium channel blockers
•Diuretics
•Vasodilators
•Adrenergic Agents
–Alpha1 blockers
–Beta blockers (cardioselective and nonselective)
–Centrally acting alpha blockers
–Combined alpha-beta blockers
–Peripheral-acting adrenergic agents
Mechanism of Action
Alpha1 Blockers (peripherally acting)
•Block the alpha1-adrenergic receptors
•The SNS is not stimulated
Result: DECREASED blood pressure
Alpha1 Blockers
•doxazosin (Cardura)
•prazosin (Minipress)
•terazosin (Hytrin)
•Stimulation of alpha1-adrenergic receptors causes HYPERtension
•Blocking alpha1-adrenergic receptors causes decreased blood pressure
Central-Acting Adrenergics
•Stimulate alpha2-adrenergic receptors
•Sympathetic outflow from the CNS is decreased
Result: decreased blood pressure
•clonidine (Catapres)
•methyldopa (Aldomet) *(drug of choice for hypertension in pregnancy)
Mechanism of Action
Adrenergic Neuronal Blockers
(peripherally acting)
•Inhibit release of norepinephrine
•Also deplete norepinephrine stores
•SNS (peripheral adrenergic nerves) is not stimulated
Result: decreased blood pressure
•reserpine
•guanadrel (Hylorel)
•guanethidine (Ismelin)
Therapeutic Uses
•Alpha1 blockers (peripherally acting)
–Treatment of hypertension
–Relief of symptoms of BPH
–Management of of severe CHF when used with cardiac glycosides and diuretics
•Central-Acting Adrenergics
–Treatment of hypertension, either alone or with other agents
–Usually used after other agents have failed due to side effects
–Also may be used for treatment of severe dysmenorrhea, menopausal flushing, glaucoma
–Clonidine is useful in the management of withdrawal symptoms in opioid- or nicotine-dependent persons
•Adrenergic neuronal blockers
(peripherally acting)
–Treatment of hypertension, either alone or with other agents
–Seldom used because of frequent side effects
Adrenergic Agents: Side Effects
Most common: dry mouth drowsiness sedation constipation
Other: headaches sleep disturbances nausea rash cardiac disturbances (palpitations)
*HIGH INCIDENCE OF ORTHOSTATIC HYPOTENSION
Angiotensin-Converting Enzyme Inhibitors
(ACE Inhibitors)
•Large group of safe and effective drugs
•Often used as first-line agents for CHF and hypertension
•May be combined with a thiazide diuretic or calcium channel blocker
Mechanism of Action
RAAS: Renin Angiotensin-Aldosterone System
•When the enzyme angiotensin I is converted to angiotensin II, the result is potent vasoconstriction and stimulation of aldosterone
•Result of vasoconstriction: increased systemic vascular resistance and increased afterload
•Therefore, increased BP
ACE Inhibitors
•Aldosterone stimulates water and sodium resorption.
•Result: increased blood volume, increased preload, and increased B
•ACE Inhibitors block the angiotensin-converting enzyme, thus preventing the formation of angiotensin II.
•Also prevent the breakdown of the vasodilating substance, bradykinin Result: decreased systemic vascular resistance (afterload), vasodilation, and therefore, decreased blood pressure
•captopril (Capoten)
•Short half-life, must be dosed more frequently than others
•enalapril (Vasotec)
•The only ACE inhibitor available in oral and parenteral forms
•lisinopril (Prinivil and Zestril) and quinapril (Accupril)
•Newer agents, long half-lives, once-a-day dosing
•Several other agents available
Therapeutic Uses
ACE Inhibitors
•Hypertension
•CHF (either alone or in combination with diuretics or other agents)
•Slows progression of left ventricular hypertrophy after an MI
•Renal protective effects in patients with diabetes Drugs of choice in hypertensive patients with CHF
Side Effects
ACE Inhibitors
•Fatigue Dizziness
•Headache Mood changes
•Impaired taste Dry, nonproductive cough, reverses when therapy is stopped
*NOTE: first-dose hypotensive effect may occur!!
Angiotensin II Receptor Blockers
(A II Blockers or ARBs)
•Newer class
•Well-tolerated
•Do not cause coughing
Mechanism of Action
•Allow angiotensin I to be converted to angiotensin II, but block the receptors that receive angiotensin II
•Block vasoconstriction and release of aldosterone
Angiotensin II Receptor Blockers
•losartan (Cozaar)
•eposartan (Teveten)
•valsartan (Diovan)
•irbesartan (Avapro)
•candesartan (Atacand)
•telmisartan (Micardis)
Therapeutic Uses
•Hypertension
•Adjunctive agents for the treatment of CHF
•May be used alone or with other agents such as diuretics
•Upper respiratory infections
•Headache
•May cause occasional dizziness, inability to sleep, diarrhea, dyspnea, heartburn, nasal congestion, back pain, fatigue
Calcium Channel Blockers
•Benzothiazepines
•Dihydropyridines Phenylalkylamines
Mechanism of Action
•Cause smooth muscle relaxation by blocking the binding of calcium to its receptors, preventing muscle contraction
•This causes decreased peripheral smooth muscle tone, decreased systemic vascular resistance
•Result: decreased blood pressure
•Benzothiazepines: –diltiazem (Cardizem, Dilacor)
•Phenylalkamines: –verapamil (Calan, Isoptin)
•Dihydropyridines: –amlodipine (Norvasc), bepridil (Vascor), nicardipine (Cardene)
–nifedipine (Procardia), nimodipine (Nimotop)
Therapeutic Uses
•Angina
•Hypertension
•Dysrhythmias
•Migraine headaches
•Cardiovascular –hypotension, palpitations, tachycardia
•Gastrointestinal –constipation, nausea
•Other –rash, flushing, peripheral edema, dermatitis
Diuretics
•Decrease the plasma and extracellular fluid volumes
•Results: decreased preload, decreased cardiac output, decreased total peripheral resistance •
•Overall effect: decreased workload of the heart, and decreased blood pressure
Mechanism of Action
Vasodilators
•Directly relaxes arteriolar smooth muscle
•Result: decreased systemic vascular response, decreased afterload, and PERIPHERAL VASODILATION
Vasodilators
•diazoxide (Hyperstat)
•hydralazine HCl (Apresoline)
•minoxidil (Loniten, Rogaine)
•sodium nitroprusside (Nipride, Nitropress)
Therapeutic Uses
•Treatment of hypertension
•May be used in combination with other agents
•Sodium nitroprusside and diazoxide IV are reserved for the management of hypertensive emergencies
Side Effects
•Hydralazine: –dizziness, headache, anxiety, tachycardia, nausea and vomiting, diarrhea, anemia, dyspnea, edema, nasal congestion
•Sodium nitroprusside: –bradycardia, hypotension, possible cyanide toxicity
Nursing Implications
•Before beginning therapy, obtain a thorough health history and head-to-toe physical examination.
•Assess for contraindications to specific antihypertensive agents.
•Assess for conditions that require cautious use of these agents.
•Educate patients about the importance of not missing a dose and taking the medications exactly as prescribed.
•Patients should never double up on doses if a dose is missed; check with physician for instructions on what to do if a dose is missed.
•Monitor BP during therapy. Instruct patients to keep a journal of regular BP checks.
•Instruct patients that these drugs should not be stopped abruptly, as this may cause a rebound hypertensive crisis, and perhaps lead to CVA.
•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.
•Remind patients that medications is only part of therapy. Encourage patients to watch their diet, stress level, weight, and alcohol intake.
•Patients should avoid smoking and eating foods high in sodium.
•Encourage supervised exercise.
•Instruct patients to change positions slowly to avoid syncope from postural hypotension.
•Patients should report unusual shortness of breath; difficulty breathing; swelling of the feet, ankles, face, or around the eyes; weight gain or loss; chest pain; palpitations; or excessive fatigue.
•Men taking these agents may not be aware that impotence is an expected effect. This may influence compliance with drug therapy.
•If patients are experiencing serious side effects, or believe that the dose or medication needs to be changed, they should contact their physician immediately.
•Hot tubs, showers, or baths; hot weather; prolonged sitting or standing; physical exercise; and alcohol ingestion may aggravate low blood pressure, leading to fainting and injury.
Patients should sit or lie down until symptoms subside.
•Patients should not take any other medications, including OTC drugs, without first getting the approval of their physician.
•Monitor for side/adverse effects
-(dizziness, orthostatic hypotension, fatigue) and for toxic effects.
•Monitor for therapeutic effects
•Blood pressure should be maintained at less than 140/90 mm Hg
Category Systemic BP (mm Hg) Diastolic BP (mm Hg)
Normal <130 <85
High normal 130-139 85-89
Hypertension
Stage 1 140-159 90-99
Stage 2 160-169 100-109
Stage 3 180-209 110-119
Stage 4 > 210 > 120
Classification of Blood Pressure
Primary Hypertension
•Specific cause unknown
•90% of the cases
•Also known as essential or idiopathic hypertension
Secondary Hypertension
•Cause is known (such as eclampsia of pregnancy, renal artery disease, pheochromocytoma)
•10% of the cases
Blood Pressure = CO x SVR
•CO = Cardiac output
•SVR = Systemic vascular resistance
Antihypertensive Agents
•Adrenergic agents
•Angiotensin-converting enzyme inhibitors
•Angiotensin II receptor blockers
•Calcium channel blockers
•Diuretics
•Vasodilators
•Adrenergic Agents
–Alpha1 blockers
–Beta blockers (cardioselective and nonselective)
–Centrally acting alpha blockers
–Combined alpha-beta blockers
–Peripheral-acting adrenergic agents
Mechanism of Action
Alpha1 Blockers (peripherally acting)
•Block the alpha1-adrenergic receptors
•The SNS is not stimulated
Result: DECREASED blood pressure
Alpha1 Blockers
•doxazosin (Cardura)
•prazosin (Minipress)
•terazosin (Hytrin)
•Stimulation of alpha1-adrenergic receptors causes HYPERtension
•Blocking alpha1-adrenergic receptors causes decreased blood pressure
Central-Acting Adrenergics
•Stimulate alpha2-adrenergic receptors
•Sympathetic outflow from the CNS is decreased
Result: decreased blood pressure
•clonidine (Catapres)
•methyldopa (Aldomet) *(drug of choice for hypertension in pregnancy)
Mechanism of Action
Adrenergic Neuronal Blockers
(peripherally acting)
•Inhibit release of norepinephrine
•Also deplete norepinephrine stores
•SNS (peripheral adrenergic nerves) is not stimulated
Result: decreased blood pressure
•reserpine
•guanadrel (Hylorel)
•guanethidine (Ismelin)
Therapeutic Uses
•Alpha1 blockers (peripherally acting)
–Treatment of hypertension
–Relief of symptoms of BPH
–Management of of severe CHF when used with cardiac glycosides and diuretics
•Central-Acting Adrenergics
–Treatment of hypertension, either alone or with other agents
–Usually used after other agents have failed due to side effects
–Also may be used for treatment of severe dysmenorrhea, menopausal flushing, glaucoma
–Clonidine is useful in the management of withdrawal symptoms in opioid- or nicotine-dependent persons
•Adrenergic neuronal blockers
(peripherally acting)
–Treatment of hypertension, either alone or with other agents
–Seldom used because of frequent side effects
Adrenergic Agents: Side Effects
Most common: dry mouth drowsiness sedation constipation
Other: headaches sleep disturbances nausea rash cardiac disturbances (palpitations)
*HIGH INCIDENCE OF ORTHOSTATIC HYPOTENSION
Angiotensin-Converting Enzyme Inhibitors
(ACE Inhibitors)
•Large group of safe and effective drugs
•Often used as first-line agents for CHF and hypertension
•May be combined with a thiazide diuretic or calcium channel blocker
Mechanism of Action
RAAS: Renin Angiotensin-Aldosterone System
•When the enzyme angiotensin I is converted to angiotensin II, the result is potent vasoconstriction and stimulation of aldosterone
•Result of vasoconstriction: increased systemic vascular resistance and increased afterload
•Therefore, increased BP
ACE Inhibitors
•Aldosterone stimulates water and sodium resorption.
•Result: increased blood volume, increased preload, and increased B
•ACE Inhibitors block the angiotensin-converting enzyme, thus preventing the formation of angiotensin II.
•Also prevent the breakdown of the vasodilating substance, bradykinin Result: decreased systemic vascular resistance (afterload), vasodilation, and therefore, decreased blood pressure
•captopril (Capoten)
•Short half-life, must be dosed more frequently than others
•enalapril (Vasotec)
•The only ACE inhibitor available in oral and parenteral forms
•lisinopril (Prinivil and Zestril) and quinapril (Accupril)
•Newer agents, long half-lives, once-a-day dosing
•Several other agents available
Therapeutic Uses
ACE Inhibitors
•Hypertension
•CHF (either alone or in combination with diuretics or other agents)
•Slows progression of left ventricular hypertrophy after an MI
•Renal protective effects in patients with diabetes Drugs of choice in hypertensive patients with CHF
Side Effects
ACE Inhibitors
•Fatigue Dizziness
•Headache Mood changes
•Impaired taste Dry, nonproductive cough, reverses when therapy is stopped
*NOTE: first-dose hypotensive effect may occur!!
Angiotensin II Receptor Blockers
(A II Blockers or ARBs)
•Newer class
•Well-tolerated
•Do not cause coughing
Mechanism of Action
•Allow angiotensin I to be converted to angiotensin II, but block the receptors that receive angiotensin II
•Block vasoconstriction and release of aldosterone
Angiotensin II Receptor Blockers
•losartan (Cozaar)
•eposartan (Teveten)
•valsartan (Diovan)
•irbesartan (Avapro)
•candesartan (Atacand)
•telmisartan (Micardis)
Therapeutic Uses
•Hypertension
•Adjunctive agents for the treatment of CHF
•May be used alone or with other agents such as diuretics
•Upper respiratory infections
•Headache
•May cause occasional dizziness, inability to sleep, diarrhea, dyspnea, heartburn, nasal congestion, back pain, fatigue
Calcium Channel Blockers
•Benzothiazepines
•Dihydropyridines Phenylalkylamines
Mechanism of Action
•Cause smooth muscle relaxation by blocking the binding of calcium to its receptors, preventing muscle contraction
•This causes decreased peripheral smooth muscle tone, decreased systemic vascular resistance
•Result: decreased blood pressure
•Benzothiazepines: –diltiazem (Cardizem, Dilacor)
•Phenylalkamines: –verapamil (Calan, Isoptin)
•Dihydropyridines: –amlodipine (Norvasc), bepridil (Vascor), nicardipine (Cardene)
–nifedipine (Procardia), nimodipine (Nimotop)
Therapeutic Uses
•Angina
•Hypertension
•Dysrhythmias
•Migraine headaches
•Cardiovascular –hypotension, palpitations, tachycardia
•Gastrointestinal –constipation, nausea
•Other –rash, flushing, peripheral edema, dermatitis
Diuretics
•Decrease the plasma and extracellular fluid volumes
•Results: decreased preload, decreased cardiac output, decreased total peripheral resistance •
•Overall effect: decreased workload of the heart, and decreased blood pressure
Mechanism of Action
Vasodilators
•Directly relaxes arteriolar smooth muscle
•Result: decreased systemic vascular response, decreased afterload, and PERIPHERAL VASODILATION
Vasodilators
•diazoxide (Hyperstat)
•hydralazine HCl (Apresoline)
•minoxidil (Loniten, Rogaine)
•sodium nitroprusside (Nipride, Nitropress)
Therapeutic Uses
•Treatment of hypertension
•May be used in combination with other agents
•Sodium nitroprusside and diazoxide IV are reserved for the management of hypertensive emergencies
Side Effects
•Hydralazine: –dizziness, headache, anxiety, tachycardia, nausea and vomiting, diarrhea, anemia, dyspnea, edema, nasal congestion
•Sodium nitroprusside: –bradycardia, hypotension, possible cyanide toxicity
Nursing Implications
•Before beginning therapy, obtain a thorough health history and head-to-toe physical examination.
•Assess for contraindications to specific antihypertensive agents.
•Assess for conditions that require cautious use of these agents.
•Educate patients about the importance of not missing a dose and taking the medications exactly as prescribed.
•Patients should never double up on doses if a dose is missed; check with physician for instructions on what to do if a dose is missed.
•Monitor BP during therapy. Instruct patients to keep a journal of regular BP checks.
•Instruct patients that these drugs should not be stopped abruptly, as this may cause a rebound hypertensive crisis, and perhaps lead to CVA.
•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.
•Remind patients that medications is only part of therapy. Encourage patients to watch their diet, stress level, weight, and alcohol intake.
•Patients should avoid smoking and eating foods high in sodium.
•Encourage supervised exercise.
•Instruct patients to change positions slowly to avoid syncope from postural hypotension.
•Patients should report unusual shortness of breath; difficulty breathing; swelling of the feet, ankles, face, or around the eyes; weight gain or loss; chest pain; palpitations; or excessive fatigue.
•Men taking these agents may not be aware that impotence is an expected effect. This may influence compliance with drug therapy.
•If patients are experiencing serious side effects, or believe that the dose or medication needs to be changed, they should contact their physician immediately.
•Hot tubs, showers, or baths; hot weather; prolonged sitting or standing; physical exercise; and alcohol ingestion may aggravate low blood pressure, leading to fainting and injury.
Patients should sit or lie down until symptoms subside.
•Patients should not take any other medications, including OTC drugs, without first getting the approval of their physician.
•Monitor for side/adverse effects
-(dizziness, orthostatic hypotension, fatigue) and for toxic effects.
•Monitor for therapeutic effects
•Blood pressure should be maintained at less than 140/90 mm Hg
**This video contains on how the Antihypertensive Drugs on our Cardiovascular System.