Antihypertensive Pharmacologic Agents

NR33

K Burger, MSEd, MSN, RN, CNEReferenced from:

Lilley et al (2005)

Pharmacology and the nursing process (4th ed). Elsevier

Categories

Adrenergic agents-Alpha blockers-Beta blockers-Alpha/Beta blockers

Angiotensin-converting enzyme inhibitorsAngiotensin II receptor blockersCalcium channel blockersVasodilatorsDiuretics

Components of Blood Pressure

Blood pressure = CO X SVRCO = cardiac outputSVR = systemic vascular resistance

Adrenergic Agents

Alpha Blockers(peripherally acting)

Prazosin (Minipress) Blocks norepinephrine

at receptor sites Sympathetic Nervous

System not stimulated Blood vessel dilation

results in decreased BP

Alpha Blockers

(centrally acting)

Clonidine (Catapres) Reduces norepinephrine

production Sympathetic Nervous

System not stimulated Blood vessel dilation

results in decreased BP

Adrenergic Agents

Beta Blockers

atenolol (Tenormin) metoprolol (Lopressor) propranolol (Inderal) Block SNS stimulation of heart; reduces SA node activity Reduces ventricular contraction rate Reduction in cardiac output results in lower BP Also used as: Antidysrhythmic, Antianginal

Adrenergic Agents

Alpha / Beta Blocker Combination

Carvedilol ( Coreg )

Dual antihypertensive effect on both CO and SVR Alpha blocker promotes vasodilation; decreased SVR Beta blocker reduces heart rate; decreased CO Overall effect = decreased BP

Adrenergic AgentsNursing Implications

Orthostatic hypotension common;take alphas @ bedtime Other side effects:

fatigue, dizziness, sedation, constipation Potentiates CNS depressants (Alcohol/Opiods) Abrupt withdrawal of central alpha blocker causes

rebound hypertension Less side effects with peripheral acting and/or

combination adrenergics Monitor HR =>60 for beta blockers

Angiotensin-Converting Enzyme InhibitorsACE Inhibitors

Inhibit the conversion of Angiotensin I to Angiotensin II resulting in:Vasodilation,decreased SVR, decreased BP Decreased aldosterone,diuresis,decreased SVR&BP

May be combined with a thiazide diuretic or calcium channel blocker

Safe and effective; often used as first line Rx Used also for: CHF, post MI to stop LVH progress Renal protective effects in patients with diabetes

ACE 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

Newer agents, long half-lives, once-a-day dosing

ACE InhibitorsNursing Implications

Dry, nonproductive cough common

Other side effects: fatigue,dizziness,headache, mood changes,taste alterations, angioedema

First-dose hypotensive effect may occur

Additive effects when given with diuretics or other antihypertensives

Antagonistic effects when given with NSAIDs

If given with K supplement may cause hyperK

Angiotensin II Receptor BlockersARBs

Losartan ( Cozaar ) Valsartan ( Diovan ) Block the binding of Angiotensin II to AT1

receptors on vessels & adrenal gland thereby:- promoting vasodilation / lower aldosterone- decreased SVR and decreased BP

Newer class and well-tolerated

ARBNursing Implications

Possible side effects:Upper respiratory infectionAngioedema & Headache

Less likely to cause hyperkalemia (unlike ACE) Can be used in pts who cannot tolerate ACE Rx Do not cause coughing Used cautiously in geriatric pts and impaired

renal function

Calcium Channel BlockersCCBs

Diltiazem (Cardizem) Verapamil ( Calan ) Nifedipine ( Procardia ) Cause smooth muscle relaxation by blocking the

binding of calcium to its receptors, preventing muscle contraction

This causes decreased peripheral smooth muscle tone, decreased SVR and BP

Slows cardiac conduction; decreases HR&CO&BP Also used as : antidysrythmic, antianginal

Calcium Channel BlockersNursing Implications

Considered safe with limited side-effects

First line drug choice

More effective in geriatric and African-American patients

Possible side effects:hypotension, dysrythmias, constipation, nausea,rash,peripheral edema, dermatitis

Vasodilators

hydralazine HCl (Apresoline) sodium nitroprusside (Nipride, Nitropress)

Directly relaxes arteriolar smooth muscle

vasodilation; decreased SVR; decreased BP May be used in combination with other agents Sodium nitroprusside is reserved for the

management of hypertensive emergencies

VasodilatorsNursing Implications

Hydralazine Side Effects: dizziness, headache, anxiety, tachycardia

Sodium Nitroprusside Side Effects: bradycardia, hypotensionControlled administration/IV infusion pump

CHECKPOINT

The physician has ordered prazosin (Minipress) for Mrs. McAdams. What patient teaching should she receive?

A. She should weigh herself daily, and report any weight loss to the physician.

B. She must increase her potassium intake by eating more bananas and apricots.

C. The impaired taste associated with the medication usually goes away in 2 to 3 weeks.

D. She should take her first dose while lying down, because there is a first-dose effect with the prazosin.

Antihypertensive Agents General Nursing Implications

Educate patients about the importance of not missing a dose, taking the medications exactly as prescribed, never doubling up on doses, and not stopping abruptly

Patients should not take any OTC drugs without first checking with MD

PO meds should be taken with meals

Educate patient on concurrent lifestyle modifications:Diet, Exercise, Stress Reduction

Instruct patients on how to monitor their own BP

Antihypertensive AgentsNursing 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 General Nursing Implications

Instruct patients to change positions slowly

Hot showers, tubs, weather, exercise, alcohol, prolonged sitting/standing may cause hypotension, dizziness, fainting

Patients should report: SOB, dyspnea, peripheral and/or angioedema, excessive weight gain, chest pain, palpitations

Men may experience impotence as expected SE

Diuretics

Main classifications:Thiazide and thiazide-likeLoopPotassium-sparing

Others: Osmotic Carbonic Anhydrase Inhibitors

Thiazide Diuretics

Hydrochlorothiazide ( HydroDIURIL )Inhibits Na reabsorption at distal tubule

resulting in diuresis; decreased SVR & BPAlso acts to relax arterioles;decrease SVRFirst line medication regimen for HTNSafe for most patients; inexpensiveOften used in combination w/ other drugs

Loop Diuretics

Furosemide (Lasix)Blocks Cl and Na reabsorption at Loop of

Henle resulting in diuresis; decreased SVR and decreased BP

Stimulate prostaglandins; vasodilation ofrenal, lung, system vessels

Rapid onset and most potent diureticCan be given once dailyEffective even in renal impaired patients

Thiazide and Loop DiureticsNursing Implications

Monitor K levels closely for hypokalemia Teach patient to eat high K foods Cross allergies may exist to sulfonamides Concurrent digoxin Rx may lead to digoxin

toxicity NSAIDS may decrease diuretic effect Concurrent antiglycemic Rx may lead to

hyperglycemia Monitor for I & O.

NCLEX QUESTION

A 66 y.o. client who is taking several medications including Digoxin and Diuril comes to the clinic complaining of not feeling well. Which of the following assessment data would indicate a potential diagnosis of digoxin toxicity?

A. chest pain, hypotension, and paresthesia

B. constipation, dry mouth, and sleep disorder

C. double vision, loss of appetite, and nausea

D. dyspnea, edema, and palpitations

Potassium-sparing Diuretics

Spironlactone ( Aldactone )Works in the collecting ductBinds and blocks aldosterone receptors

resulting in blocked Na water reabsorption;decreased SVR and BP

Considered a weak diureticOften used in conjunction with more potent

K depleting diuretics

Potassium-sparing DiureticNursing Implications

Monitor K levels closely for hyperkalemiaEspecially with renal impairment, use of potassium supplements, or ACE drugs

May cause gynecomastia, impotence in men; amenorrhea, and post-menopausal bleeding in women.

Other side effects: dizziness, ha, cramps, nausea,diarrhea.

DiureticsGeneral Nursing Implications

Instruct patient to take early in the day to avoid sleep disturbances

Geriatric patients more sensitive to fluid balance changes; caution for postural hypotension

Monitor weights, potassium levels as well as Na and Cl

Instruct patients to notify MD if ill with vomiting and/or diarrhea