Transcript HTN Medications

Antihypertensive
Pharmacologic Agents
NUR133 Lecture #11
K Burger, MSEd, MSN, RN, CNE
Referenced 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 inhibitors
Angiotensin II receptor blockers
Calcium channel blockers
Vasodilators
Diuretics
Adrenergic Agents
Alpha Blockers
Alpha Blockers
(peripherally acting)
(centrally acting)
 Prazosin (Minipress)
 Clonidine (Catapres)
 Blocks norepinephrine
at receptor sites
 Sympathetic Nervous
System not stimulated
 Blood vessel dilation
results in decreased BP
 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 Agents
Nursing 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 Inhibitors
ACE 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 Inhibitors
Nursing Implications
 Dry, nonproductive cough common
 Other side effects:
fatigue,dizziness,headache, mood changes
 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 Blockers
ARBs
 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
ARB
Nursing Implications
 Common side effects:
Upper respiratory infection
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 Blockers
CCBs
 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 Blockers
Nursing 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
Vasodilators
Nursing Implications
Hydralazine
Side Effects: dizziness, headache, anxiety,
tachycardia
Sodium Nitroprusside
Side Effects: bradycardia, hypotension
Controlled administration/IV infusion pump
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 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
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-like
Loop
Potassium-sparing
Others:
 Osmotic
 Carbonic Anhydrase Inhibitors
Thiazide Diuretics
Hydrochlorothiazide ( HydroDIURIL )
Inhibits Na reabsorption at distal tubule
resulting in diuresis; decreased SVR & BP
Also acts to relax arterioles;decrease SVR
First line medication regimen for HTN
Safe for most patients; inexpensive
Often 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 of
renal, lung, system vessels
Rapid onset and most potent diuretic
Can be given once daily
Effective even in renal impaired patients
Thiazide and Loop Diuretics
Nursing 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
Potassium-sparing Diuretics
Spironlactone ( Aldactone )
Works in the collecting duct
Binds and blocks aldactone receptors
resulting in blocked Na water reabsorption;
decreased SVR and BP
Considered a weak diuretic
Often used in conjunction with more potent
K depleting diuretics
Potassium-sparing Diuretic
Nursing Implications
Monitor K levels closely for hyperkalemia
Especially with renal impairment, use of
potassium supplements, or ACE drugs
May cause gynecomastia, amenorrhea,
and post-menopausal bleeding
Other side effects: dizziness, ha, cramps,
nausea,diarrhea.
Diuretics
General 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