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Drugs Affecting Blood Pressure


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Blood Pressure (BP)
cardiac output x peripheral resistance
Cardiac Output (CO)
Affected by HR, contractility, venous return and blood volume
Peripheral Resistance (PR)
Determined by diameter and length of vessel
Arteriolar constriction
Types of Hypertension
Primary (Essential) Hypertension - No identifiable cause
Secondary Hypertension - Identifiable cause
Renal disease
Oral contraceptive use
Renovascular disease
Cushings syndrome
Consequences of Hypertension
Myocardial Infarction
Heart failure
Kidney disease
Degree of injury related to degree of elevation/higher pressure higher risk
Asymptomatic until long after injury has developed
Benefits of Lowering BP
↓ morbidity
↑ lifespan
↓ incidence of stroke
↓ incidence of MI
↓ incidence of heart failure
What are some identifiable causes of hypertension?
Oral contraceptives
Factors that increase CV risk
Target organ damage
Major CV risk factors
Goals of treatment of hypertension
↓ CV and renal morbidity and mortality without ↓ quality of life
Therapeutic Interventions for hypertension
Healthy lifestyle changes
Antihypertensive drugs
Classes of Antihypertensive Drugs

Sympatholytics (Adrenergic Antagonists)- Beta-adrenergic blockers, Alpha 1 Blockers, Alpha/Beta Blockers, Centrally Acting Alpha2, Agonist

Others - ACE Inhibitors, Angiotensin Receptor Blockers (ARB’s), Calcium Channel Blockers, Direct Acting Vasodilators
Sympatholytics (Adrenergic Antagonists)
Alpha 1, Alpha 2, Beta 1, Beta 2
Alpha 1 Sympatholytics (Adrenergic Antagonists)
Eye, arterioles of skin viscera and mucus membranes, veins, male sex organs, bladder neck and prostatic capsule
Alpha 2 Sympatholytics (Adrenergic Antagonists)
Presynaptic nerve terminals
Beta 1 Sympatholytics (Adrenergic Antagonists)
Heart, kidneys
Beta 2 Sympatholytics (Adrenergic Antagonists)
Arterioles of heart, lungs and skeletal muscle, bronchi, uterus, liver, skeletal muscle
Actions of Beta Blockers
Block the sympathetic nervous system
Beta adrenergic receptors
↓ HR
↓ force of contraction
Slows conduction through the AV node
Therapeutic Uses of Beta Blockers
Angina Pectoris
Cardiac dysrhythmias
Heart failure
Adverse Effects of Beta Blockers
↓ cardiac output
Precipitation of heart failure
AV heart block
Reflex tachycardia
Bronchoconstriction inhibition of glycogenolysis
Beta Blockers
Propranolol (Inderal), Metoprolol (Lopressor)
Action of Propranolol (Inderal)
Nonselective beta adrenergic antagonist (Beta1 and beta2)
↓ HR, ↓force of ventricular contraction and slow impulse conduction through the AV node, supress secretion of renin (Beta1)
Bronchoconstriction, vasoconstriction, inhibitions of glycogenolysis (Beta 2)
Lipid soluble – easily crosses membranes
Well absorbed
Widely distributed
Hepatic metabolism
Excreted in the urine
Drug interactions with Propranolol (Inderal)
Calcium channel blockers
Action of Metoprolol (Lopressor)
Cardioselective (Beta 1 only)
Therapeutic uses of Metoprolol (Lopressor)
HTN, heart failure and MI, Hepatic metabolism
Renal excretion
Adverse Effects of Metoprolol (Lopressor)
Bradycardia, ↓ CO, AV block, rebound tachycardia with abrupt discontinuation
Action of Alpha blockers
Block alpha receptors on blood vessels
Therapeutic Uses of Alpha blockers
Essential Hypertension
Adverse effects of Alpha blockers
Orthostatic Hypertension
Reflex tachycardia
Nasal congestion
Inhibition of ejaculation
Alpha blockers Drugs
Prazosin (Minipress)
Terazosin (Hytrin)
Doxazosin (Cardura)
Action of Alpha/Beta blocker - Labetolol (Normodyne)
Blocks beta 1 and beta 2 and selective alpha 1
Alpha blocking cause peripheral vasodilation
Beta blocking prevents reflex tachycardia
Action of Centrally Acting Alpha Agonists - Clonidine (Catapres)
Inhibits sympathetic nervous system response and reduces sympathetic outflow from the CNS
↓ HR, BP,vasocinstriction and vascular resistance
Severe rebound HTN if discontinued
Action of Centrally Acting Alpha Agonists - Methyldopa (Aldomet)
Displaces norepinephrine form storage sites
Drug of choice for pregnant women withHTN
renin-angiotensin-aldosterone system
Hypothalamus - pituitary gland - renin -

Angiotensin I -
Little biologic activity

Angiotensin II
Release of aldosterone
Alteration of cardiac and vascular structure
Action of ACE Inhibitors -
Captopril (Capoten)
Blocks the conversion of angiotensin I to angiotensin II

Prevents Na and H20 retention

Decreases peripheral vascular resistance
Significant adverse effects of ACE Inhibitors
First dose hypotension
Renal failure
ACE Inhibitors contraindicated in 2nd and 3rd trimesters
ACE Inhibitors - Enalapril
is the only ACE inhibitor that can be given IV.
Action of Angiotensin II Receptor Antagonists (ARB) - Losartan (Cozaar)
Prevents angiotensin II from binding to receptors in many tissues, thus blocking the vasoconstricting and aldosterone-secreting effects of angiotensin II
Decreases peripheral vascular resistance
Does not cause” ACE cough” or hyperkalemia
Angioedema is common
ARB’s contraindicated in 2nd and 3rd trimesters
Action of Calcium Antagonists - (Calcium Channel Blockers )
Prevent calcium from entering the cells
Treatment of HTN, angina, and cardiac dysrhythmias
Action of Calcium Channel Blockers -
Verapamil (Calan)
Blocks Ca channels in blood vessels and in the heart
Essential HTN, angina, and cardiac dysrhythmias
Direct effects of Calcium Channel Blockers
↓arterial pressure
↓AV nodal conduction
↓force of contraction
↑coronary perfusion
Reflex responses
Indirect effects of Calcium Channel Blockers
Barroreceptor activated
Increased firing of sympathetic nerves to the heart
Direct and indirect negate each other
Drug interactions with Beta blockers
Action of Calcium Antagonists -
Diltiazem (Cardizem)
Inhibits calcium ion influx, reduce afterload
Inhibit coronary artery spasm
Action of Calcium Antagonists -
Nifedipine (ProcardiaXL, Adalat)
Inhibits calcium ion influx
Vasodilating effects on coronary and peripheral arterioles
Does not slow AV node conduction but can cause cardiosuppression in toxic doses
Adverse effects of Nifedipine (ProcardiaXL, Adalat)
Reflex tachycardia
Common adverse effects for oral preparations of Calcium Antagonists
GI: constipation, nausea
CV: HA dizziness
What nursing interventions should be done with Calcium Antagonists
Monitor and treat adverse effects supportively
Overdose: IV calcium chloride or calcium gluconate
What are the actions of Direct-acting vasodilators -
Hydralazine (Apresoline)
↓Peripheral resistance
Adjunct with other antihypertensives
Used with beta blockers or clonidine to prevent reflex tachycardia from vasodilation
With diuretics to offset fluid retention from ↑ production of angiotensin II
What is the adverse effect of Direct-acting vasodilators -
Hydralazine (Apresoline)
Lupus like syndrome
What are the actions and nursing interventions of Direct-acting vasodilators - Nitorprusside (Nitorpress)
Used to treat hypertensive crisis (DBP>120)
Directly relaxes vascular smooth muscle
Dilates veins more than arteries
↓ preload and afterload
↓ BP dramatically
IV use only
MUST use a pump
Protect form light
Monitor BP often
What drugs are used in Treatment of Hypotension
What is the Prototype agent of Vasopressors?
dopamine (Intropin)
Adverse effects of dopamine (Intropin)
CV system effects
What are the actions of dopamine
Catecholamine and a precursor to NE
Vasopressor used in treating shock
Stimulation of alph-1, beta-1 and dopamine receptors is dose dependent
What are the nursing interventions for dopamine
IV administration only in acute care settings
Invasive monitoring, pump
Weight based dosing
Correct hypovolemia first
What are the contraindications for dopamine
Uncorrected tachyarrhythmias

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