Drugs used to treat Hypertension
HTN = BP > 140/90
Assos. With: premature death vascular disease of brain,
heart,kidneys
Goal of treatment
Prolong useful life by preventing cardiovascular problems by reducing
BP < 140/90
Blood Pressure
Review of physiology BP caused by: _________ Systolic pressure: __________ Diastolic pressure: __________
Blood Pressure Primary Factors
1. Cardiac output2. Peripheral resistance3. Blood Volume
Initial tx. of hypertension Lifestyle modification first No smoking Weight control Reduce alcohol intake Decrease stress Sodium control
Treatment of hypertension Lifestyle modification first Initial tx. drug- diuretic or B-blocker Low dose first, increase dose if
necessary 2nd med. if needed Most respond with diuretic and one
other medication (stepped care) Tx pump, fluid volume, or PVR
Drugs to treat hypertension
5 primary classes1. Diuretics2. Calcium channel blockers3. Angiotesin converting enzyme
(ACE) inhibitors4. Autonomic nervous system agents5. Direct acting vasodilators
Diuretics Tx: mild to moderate HTN First drug of tx. Also tx. heart failure or kidney
disease Few adverse side effects Used with other antihypertensives
to enhance effectiveness
DiureticsAction
Reduce blood volume through urinary excretion of water and electrolytes
1. Electrolyte imbalances can occur (mainly hypokalemia)
2. Depends on type of diuretic
Diuretics
Most efficient: Loop or High-ceiling Reduce edema assos. with CHF Increase UO even if blood flow to kidney
is diminished Hypokalemia KCL supplement given Lasix, Demadex, Bumex
Diuretics
Most widely prescribed: Thiazides Mild to moderate HTN-primarily Hydrodiuril – hydrochlorothiazide
(HCTZ) Hypokalemia Potassium supplement- KCL
Diuretics Potassium-sparing:prevent
hypokalemia Mild HTN Used in combination with other
diuretics No supplement taken Watch for hyperkalemia
Side effects Orthostatic hypotension Dry mouth,irritation Report: Electrolyte imbalance-
hypokalemia (potasium<3.5) Disorientation dehydration
Implications for use
Optimal time to admin.= AM Check VS Accurate intake and output Daily weights Monitor electrolyte imbalances
Calcium Channel Blockers
Emerged as major drug to tx. HTN Used for arrythmias also Alternative to B-blocker (hx.
Asthma)
Calcium Channel Blockers
Action:blocks ca+ access to muscle cells
contractility + conductivity of the ______________________ demand for oxygen PVR (relaxing arterioles)
Calcium Channel Blockers Examples Verapamil Very
Procardia (nifedipine)-HTN Nice
Cardizem (diltiazem)-arrythmias Drugs
Calcium Channel Blockers SIDE EFFECTS
BP Bradycardia May precipitate A-V block Headache Abdominal discomfort Peripheral edema
Angiotensin-Converting Enzyme Inhibitors “ACE” inhibitors Mainstay of oral vasodilator
therapy Major breakthrough in tx. of HTN More effective when used with
diuretics
ACE INHIBITORS
Angiotensin Converting Enzyme (ends in PRIL)
captopril enalapril benzapril(Capoten) (Vasotec) (Lotensin)
RENIN-ANGIOTENSIN-ALDOSTERONE AXN. BP
excrete renin
formation of angiotensin I angiotensin II = potent vasodilator Aldosterone release Na and H2O
ACE INHIBITORS ACTION
peripheral vascular resistanse without
Ø cardiac outputØ cardiac rate Ø cardiac contractility
Advantages Infrequent orthostatic hypotension Lack of aggravation of pulmonary
dx. Lack of aggravation with DM Increase renal blood flow
Side effects
Headache Orthostatic hypotension-infrequent Cough GI distress
Drug interactions Diuretics Alcohol Beta-blockers
All the above enhance the effects
Adrenergic ReceptorsReview of ANS
Sympathetic Nervous System Alpha 1 = vasoconstriction Alpha 2 = feedback/vasodilation Beta 1 = increases heart rate Beta 2 = bronchodilation
Beta Adrenergic Blocking Agents Known as Beta-blockers Axn: Inhibit cardiac response to
sympathetic nerve stimulation by blocking Beta receptors
Decreases heart rate and C.O. Decreases blood pressure
Beta Adrenergic Blocking Agents
Examples – “olol” names
Beta 1: Atenolol Beta 1 and 2: Propranolol
Nursing Implications
Can not be abruptly discontinued
Check baseline b.p. Check hx. of resp. condition-
aggravates bronchoconstriction
Side effects
Bradycardia Bronchospasm, wheezing Diabetic: hypoglycemia Heart failure:
edema,dyspnea,rhales
Interactions Antihypertensives- additive effect B-adrenergic agents- inhibit axn. Enzyme inducing agents-enhance
metabolism Indomethacin and salicylates:<
controll
Alpha-1 adrenergic blockers
Alternative if B-blockers and diuretics do not work
Also used to tx. mild to mod. urinary obstructive dx. (BPH)
Alpha-1 Adrenergic Blocking Agents
Action: Block postsynaptic alpha-1
adrenergic receptors to produce arteriolar and venous vasodilation
Reduces peripheral-vascular resistance
Side effects Drowsiness Headache Dizziness,tachycardia,fainting Weakness,lethargy
Interactions: other antihypertensives (enhance effects)
Clinical Implications Side effects most prevalent with
first dose Warn pt. that this is nl. Instruct pt. to lie down if
dizzy,weak,etc.
Examples of Apha-1 blockers
Cardura (doxizosin) Minipress (prazosin) Hytrin (terazosin)
Centrally Acting Alpha-2 Agonists Stimulate Alpha-2 receptors in
brainstem Decreases HR, SBP and DBP More frequent side effects –
drowsiness, dry mouth, dizziness Never suddenly DC = rebound HTN Clonidine – Catapres ( available in
TTS) Methyldopa - Aldomet
Direct Acting Vasodilators Action: dirct arteriolar smooth
muscle relaxation, decreasing PVR Uses: HTN, renal dx., toxemia of
pregnancy Ex: Apresoline, Minoxidel SE: tachycardia, orthostatic
hypotension,dizziness, palpitations, nausea, nasal congestion
Client Teaching forAntihypertensive drugs Take medication as prescribed Never discontinue without approval of
healthcare provider Incorporate lifestyle changes, even if
medication brings BP within nl. Limits Check BP on regular basis and report
significant variations (and pulse) Get out of bed slowly
Client Teaching forAntihypertensive drugs Increase intake of potassium-rich
foods, unless taking potassium sparing diuretics
Weigh regularly and report abnormal weight gains or losses
Do not take OTC drugs without checking with healthcare provider