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Antihypertensive Agents
PRADITA DIAH PERMATASARI
Hypertension
High blood pressure Normal: Systolic < 130 mm
Hg Diastolic < 85 mm Hg
Classification of Blood PressureCategory Systemic BP (mm Hg) Diastolic BP (mm Hg)
Normal <120 <80
prehipertensi 120-139 80-89
HypertensionStage 1 140-159 90-99Stage 2 160 100
Classification of Blood PressurePrimary Hypertension Specific cause unknown 90% of the cases Also known as essential or idiopathic
hypertensionSecondary 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
Medications used to treat hypertension
Antihypertensive Agents: Categories Adrenergic agents Angiotensin-converting enzyme inhibitors Angiotensin II receptor blockers Calcium channel blockers Diuretics Vasodilators
Antihypertensive Agents: Categories
Adrenergic Agents Alpha1 blockers Beta blockers (cardioselective and nonselective) Centrally acting alpha blockers Combined alpha-beta blockers Peripheral-acting adrenergic agents
Antihypertensive Agents: Mechanism of Action
Adrenergic AgentsAlpha1 Blockers (peripherally acting) Block the alpha1-adrenergic receptors The SNS is not stimulated
Result: DECREASED blood pressure
Stimulation of alpha1-adrenergic receptors causes HYPERtension
Blocking alpha1-adrenergic receptors causes decreased blood pressure
Antihypertensive Agents:
Adrenergic AgentsAlpha1 Blockers doxazosin (Cardura) prazosin (Minipress) terazosin (Hytrin)
Antihypertensive Agents: Mechanism of ActionAdrenergic AgentsCentral-Acting Adrenergics Stimulate alpha2-adrenergic
receptors Sympathetic outflow from the CNS is
decreased
Result: decreased blood pressure
Antihypertensive Agents:
Adrenergic AgentsCentral-Acting Adrenergics clonidine (Catapres) methyldopa (Aldomet)
(drug of choice for hypertension in pregnancy)
Antihypertensive Agents: Mechanism of ActionAdrenergic AgentsAdrenergic Neuronal Blockers
(peripherally acting) Inhibit release of norepinephrine Also deplete norepinephrine stores SNS (peripheral adrenergic nerves) is
not stimulated
Result: decreased blood pressure
Antihypertensive Agents:
Adrenergic AgentsAdrenergic Neuronal Blockers
(peripherally acting) reserpine guanadrel (Hylorel) guanethidine (Ismelin)
Antihypertensive Agents: Adrenergic Agents
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
Antihypertensive Agents: Adrenergic Agents
Therapeutic Uses 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
Antihypertensive Agents: Adrenergic AgentsTherapeutic Uses Adrenergic neuronal blockers
(peripherally acting) Treatment of hypertension, either alone or with
other agents Seldom used because of frequent side effects
Antihypertensive Agents: Adrenergic AgentsSide EffectsMost common: dry mouthdrowsinesssedation constipationOther: headaches sleep disturbances nausearashcardiac disturbances (palpitations)
HIGH INCIDENCE OF ORTHOSTATIC HYPOTENSION
Antihypertensive Agents: CategoriesAngiotensin-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
Antihypertensive Agents: Mechanism of Action
ACE Inhibitors
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
Antihypertensive Agents: Mechanism of ActionACE Inhibitors Aldosterone stimulates water and
sodium resorption. Result: increased blood volume,
increased preload, and increased B
Antihypertensive Agents: Mechanism of ActionACE Inhibitors 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
Antihypertensive AgentsACE Inhibitors 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
Antihypertensive Agents: Therapeutic UsesACE 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
Antihypertensive Agents: Side EffectsACE Inhibitors Fatigue Dizziness Headache Mood changes Impaired taste
Dry, nonproductive cough, reverses when therapy is stopped
NOTE: first-dose hypotensive effect may occur!!
Antihypertensive Agents: CategoriesAngiotensin II Receptor Blockers (A II Blockers or
ARBs) Newer class Well-tolerated Do not cause coughing
Antihypertensive Agents: Mechanism of ActionAngiotensin II Receptor Blockers Allow angiotensin I to be converted to
angiotensin II, but block the receptors that receive angiotensin II
Block vasoconstriction and release of aldosterone
Antihypertensive Agents:
Angiotensin II Receptor Blockers losartan (Cozaar) eposartan (Teveten) valsartan (Diovan) irbesartan (Avapro) candesartan (Atacand) telmisartan (Micardis)
Antihypertensive Agents: Therapeutic UsesAngiotensin II Receptor Blockers Hypertension Adjunctive agents for the treatment
of CHF May be used alone or with other
agents such as diuretics
Antihypertensive Agents: Side EffectsAngiotensin II Receptor Blockers Upper respiratory infections Headache May cause occasional dizziness,
inability to sleep, diarrhea, dyspnea, heartburn, nasal congestion, back pain, fatigue
Antihypertensive Agents: CategoriesCalcium Channel Blockers Benzothiazepines Dihydropyridines Phenylalkylamines
Antihypertensive Agents: Mechanism of ActionCalcium Channel Blockers 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
Antihypertensive Agents
Calcium Channel Blockers Benzothiazepines:
diltiazem (Cardizem, Dilacor) Phenylalkamines:
verapamil (Calan, Isoptin) Dihydropyridines:
amlodipine (Norvasc), bepridil (Vascor), nicardipine (Cardene)
nifedipine (Procardia), nimodipine (Nimotop)
Antihypertensive Agents: Therapeutic UsesCalcium Channel Blockers Angina Hypertension Dysrhythmias Migraine headaches
Antihypertensive Agents: Side EffectsCalcium Channel Blockers Cardiovascular
hypotension, palpitations, tachycardia Gastrointestinal
constipation, nausea Other
rash, flushing, peripheral edema, dermatitis
Antihypertensive Agents: DiureticsDecrease the plasma and extracellular fluid
volumesResults: decreased preload
decreased cardiac output decreased total peripheral resistance
Overall effect: decreased workload of the heart, and decreased blood pressure
Antihypertensive Agents: Mechanism of Action
Vasodilators
Directly relaxes arteriolar smooth muscle Result: decreased systemic vascular
response, decreased afterload, andPERIPHERAL VASODILATION
Antihypertensive Agents
Vasodilators diazoxide (Hyperstat) hydralazine HCl (Apresoline) minoxidil (Loniten, Rogaine) sodium nitroprusside (Nipride,
Nitropress)
Antihypertensive Agents: Therapeutic UsesVasodilators Treatment of hypertension May be used in combination with
other agents Sodium nitroprusside and diazoxide
IV are reserved for the management of hypertensive emergencies
Antihypertensive Agents: Side EffectsVasodilators Hydralazine:
dizziness, headache, anxiety, tachycardia, nausea and vomiting, diarrhea, anemia, dyspnea, edema, nasal congestion
Sodium nitroprusside: bradycardia, hypotension, possible
cyanide toxicity
Antihypertensive Agents: 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.
Antihypertensive Agents: Nursing Implications 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.
Antihypertensive Agents: Nursing Implications 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.
Antihypertensive Agents: Nursing Implications 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.
Antihypertensive Agents: Nursing Implications 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.
Antihypertensive Agents: Nursing Implications 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.
Antihypertensive Agents: Nursing Implications 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.
Antihypertensive Agents: Nursing Implications 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
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