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Drugs used to treat
Hypertension
HTN = BP > 140/90
Assos. With:
premature deathvascular disease of brain, heart,kidneys
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Goal of treatment
Prolong useful life by preventingcardiovascular problems by reducingBP < 140/90
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Blood Pressure
Review of physiologyBP caused by: _________Systolic pressure: __________
Diastolic pressure: __________
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Blood PressurePrimary Factors
1. Cardiac output2. Peripheral resistance
3. Blood Volume
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Initial tx. of hypertensionLifestyle modification firstNo smokingWeight controlReduce alcohol intake
Decrease stressSodium control
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Treatment of hypertensionLifestyle modification firstInitial tx. drug- diuretic or B-blockerLow dose first, increase dose ifnecessary2nd med. if needed
Most respond with diuretic and oneother medication (stepped care)Tx pump, fluid volume, or PVR
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Drugs to treat hypertension5 primary classes
1. Diuretics2. Calcium channel blockers3. Angiotesin converting enzyme (ACE)
inhibitors4. Autonomic nervous system agents5. Direct acting vasodilators
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DiureticsTx: mild to moderate HTNFirst drug of tx.
Also tx. heart failure or kidney diseaseFew adverse side effects
Used with other antihypertensives toenhance effectiveness
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Diuretics
Action
Reduce blood volume through urinaryexcretion of water and electrolytes
1. Electrolyte imbalances can occur(mainly hypokalemia)
2. Depends on type of diuretic
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DiureticsMost efficient: Loop or High-ceiling
Reduce edema assos. with CHFIncrease UO even if blood flow to kidney isdiminished
HypokalemiaKCL supplement givenLasix, Demadex, Bumex
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Diuretics
Most widely prescribed: ThiazidesMild to moderate HTN-primarilyHydrodiuril hydrochlorothiazide(HCTZ)HypokalemiaPotassium supplement- KCL
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DiureticsPotassium-sparing:prevent hypokalemiaMild HTNUsed in combination with other diureticsNo supplement taken
Watch for hyperkalemia
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Side effectsOrthostatic hypotensionDry mouth,irritation
Report:Electrolyte imbalance- hypokalemia(potasium
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Calcium Channel Blockers
Emerged as major drug to tx. HTNUsed for arrythmias also Alternative to B-blocker (hx. Asthma)
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Calcium Channel Blockers Action:
blocks ca+ access to muscle cellscontractility +conductivity of the
______________________demand for oxygenPVR (relaxing arterioles)
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Calcium Channel Blockers
Examples Verapamil Very
Procardia (nifedipine)-HTN Nice
Cardizem (diltiazem)-arrythmias Drugs
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Calcium Channel BlockersSIDE EFFECTS
BPBradycardiaMay precipitate A-V block
Headache Abdominal discomfortPeripheral edema
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Angiotensin-Converting
Enzyme Inhibitors ACE inhibitors Mainstay of oral vasodilator therapyMajor breakthrough in tx. of HTNMore effective when used with diuretics
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ACE INHIBITORS Angiotensin
C onverting
E nzyme (ends in PRIL )
capto pril enala pril benza pril(Capoten) (Vasotec) (Lotensin)
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RENIN-ANGIOTENSIN-
ALDOSTERONE AXN. BP
excrete renin
formation of angiotensin I angiotensin II = potent vasodilator Aldosterone release Na and H2O
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ACE INHIBITORS ACTION
peripheral vascular resistanse without
cardiac output
cardiac rate cardiac contractility
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AdvantagesInfrequent orthostatic hypotensionLack of aggravation of pulmonary dx.Lack of aggravation with DMIncrease renal blood flow
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Side effects
HeadacheOrthostatic hypotension-infrequentCough
GI distress
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Drug interactionsDiuretics
AlcoholBeta-blockers
All the above enhance the effects
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Adrenergic Receptors
Review of ANS
Sympathetic Nervous System Alpha 1 = vasoconstriction Alpha 2 = feedback/vasodilation
Beta 1 = increases heart rateBeta 2 = bronchodilation
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Beta Adrenergic Blocking
AgentsKnown as Beta-blockers
Axn: Inhibit cardiac response tosympathetic nerve stimulation byblocking Beta receptorsDecreases heart rate and C.O.Decreases blood pressure
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Beta Adrenergic Blocking
AgentsExamples olol names
Beta 1: AtenololBeta 1 and 2: Propranolol
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Nursing Implications
Can not be abruptly discontinuedCheck baseline b.p.Check hx. of resp. condition-aggravatesbronchoconstriction
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Side effects
BradycardiaBronchospasm, wheezingDiabetic: hypoglycemia
Heart failure: edema,dyspnea,rhales
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Interactions Antihypertensives- additive effectB-adrenergic agents- inhibit axn.Enzyme inducing agents-enhancemetabolismIndomethacin and salicylates:< controll
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Alpha-1 adrenergic blockers
Alternative if B-blockers and diureticsdo not work
Also used to tx. mild to mod. urinaryobstructive dx. (BPH)
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Alpha-1 Adrenergic Blocking
Agents Action:
Block postsynaptic alpha-1 adrenergicreceptors to produce arteriolar andvenous vasodilationReduces peripheral-vascular resistance
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Side effectsDrowsinessHeadacheDizziness,tachycardia,faintingWeakness,lethargy
Interactions: other antihypertensives(enhance effects)
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Clinical ImplicationsSide effects most prevalent with firstdoseWarn pt. that this is nl.Instruct pt. to lie down ifdizzy,weak,etc.
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Examples of Apha-1 blockers
Cardura (doxizosin)Minipress (prazosin)Hytrin (terazosin)
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Centrally Acting Alpha-2
AgonistsStimulate Alpha-2 receptors inbrainstem
Decreases HR, SBP and DBPMore frequent side effects drowsiness, dry mouth, dizziness
Never suddenly DC = rebound HTNClonidine Catapres ( available in TTS)Methyldopa - Aldomet
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Direct Acting Vasodilators Action: dirct arteriolar smooth musclerelaxation, decreasing PVR
Uses: HTN, renal dx., toxemia ofpregnancyEx: Apresoline, Minoxidel
SE: tachycardia, orthostatichypotension,dizziness, palpitations,nausea, nasal congestion
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Client Teaching for
Antihypertensive drugsTake medication as prescribedNever discontinue without approval of
healthcare providerIncorporate lifestyle changes, even ifmedication brings BP within nl. Limits
Check BP on regular basis and reportsignificant variations (and pulse)Get out of bed slowly
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Client Teaching for
Antihypertensive drugsIncrease intake of potassium-rich foods,unless taking potassium sparing
diureticsWeigh regularly and report abnormalweight gains or losses
Do not take OTC drugs withoutchecking with healthcare provider