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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