Antihypertensive Drugs Flashcards
Preload
tension exerted by blood on the chamber wall before systole
determined by the volume of blood in the chamber at the end of diastole
end of diastolic volume (EDV)
Afterload
tension developed in the chamber to pump blood out
Left ventricle afterload is determined by peripheral resistance/Blood Pressure
End of Systolic Volume
volume of blood remaining in the ventricle after systole
indicator of cardiac emptying and left ventricle function
End diastolic volume
volumtole
determines the preload
larger EDV = higher contractility during systole
dependent on venous return
Stroke volume
EDV-ESV
ventricular ejection fraction
Fraction of blood ejected from the ventricle after systole
4 stages of hypertension
Normal
Prehypertension
Stage 1 Hypertension
Stage 2 Hypertension
Compelling Indications of hypertension
POST MY high cardiovascular risk heart failure diabetes mellitus chronic kidney disease previous stroke
Classification of BP
-Hypertension can be defined by its cause
essential, idiopathic, or primary hypertension is unknown
secondary hypertension is a known cause
Primary(Essential) Hypertension causes
most prevalent type more prevalent in african americans less prevalent in mexican americans heredity high salt intake tobacco diet age males
secondary hypertension causes
less prevalent secondary kidney disease renal artery disease aldosteronism phenochromocytoma thyroid disorders obesity drugs
drugs that may cause hypertension
NSAIDs Corticosteroids Licorice Sympathomimetics Oral contraceptives Excess alcohol
thiazide-type diuretics
should be the initial drug therapy for most patients with hypertension(alone or with other drug classes)
antihypertensive drugs
adrenergic drugs angiotensin converting enzyme inhibitors (ACE) Angiotensin 2 receptor blockers calcium channel blockers diuretics vasodilators
centrally and peripherally acting neuron blockers
- reserpine is the only drug in this class
- rarely used, but still available
- peripherally it depletes epinephrine from postganglionic sympathetic nerve terminals
- reduces sympathetic stimulation of the heart and blood vessels
- this results in a drop in cardiac output and blood pressure
- centrally reserpine depletes serotonin and catecholamines from neurons in the central nervous system, causing deep emotional depression
- absolutely contraindicated in patients with a history of depression
centrally acting alpha2 receptor agonists
stimulate alpha2 adrenergic reseptors in the brain
decrease sympathetic outflow from the CNS
decrease norepinephrine production
stimulate alpha2 adrenergic receptors, thus reducing renin activity in the kidneys
results in decreased blood pressure
centrally acting alpha2 receptor agonists drugs
clonidine
methyldopa: can be used for hypertension in pregnancy
indications for using centrally acting alpha receptor agonists
- treatment of hypertension, either alone or with other drugs: usually a diuretic
- usually used after other drugs have failed because of adverse effects(orthostatic hypertension, fatigue, dizziness)
- may be used for severe dysmenorrhea, menopausal flushing, and glaucoma
- clonidine is useful in the management of withdrawal symptoms in opioid or nicotine-dependent persons
peripheral alpha1 blockers
block alpha1 adrenergic receptors alpha 1 adrenergic receptors dilates both arteries and veins might increase urinary flow rates decrease outflow obstruction by preventing smooth muscle contractions in the bladder, neck, and urethra
examples of peripherally acting alpha 1 receptor blockers
doxazosin
terazosin
prazosin
indications for use of peripheral alpha 1 blockers
- treatment of hypertension
- some used to relieve symptoms of BPH(tamsulosin)
- management of severe heart failure when used with cardiac glycosides and diuretics
peripherally acting beta receptor blockers
- reduce blood pressure by reducing heart rate through beta blockade
- cause reduced secretion of renin resulting in reduction of angiotensin 2 mediated vasoconstriction and aldosterone mediated volume expansion
- long-term use causes reduced peripheral vascular resistance
- result is decreased blood pressure
non-selective beta vlockers
propanolol
nadolol
timolol
cardioselective beta blockers
atenolol
metoprolol
penbutolol
peripherally acting dual alpha 1 and beta receptor blockers
- block alpha 1 adrenergic receptors
- reduction of heart rate through a beta 1 receptor blockade
- vasodilation through an alpha 1 receptor blockade
- result in decreased blood pressure
peripherally acting dual alpha1 and beta receptor blockers
- labetalol
- carvedilol
adverse effects of adrenergic drugs
high incidence of orthostatic hypertension bradycardia with reflex tachycardia dry mouth drowsiness dizziness depression edema constipation impotence
contraindications for adrenergic drugs
known drug allergy
acute heart failure
concurrent use of monoamine oxidase inhibitor
severe mental depression
peptic ulcer disease
severe liver or kidney disease
asthma if the patient is taking a nonselective beta blocker
interactions of adrenergic drugs
additive CNS depression when taken with alcohol, benzodiazepines, and opioids
ACE inhibitors
large group of safe and effective drugs
often used as first line drugs for heart failure and hyper tension
may be combined with a thiazide diuretic or calcium channel blocker
renin-angiotensin aldosterone system
inhibit angiotensin converting enzyme(this enzyme converts angiotensin 1 to angiotensin 2 throguh the action of renin)
angiotensin 2 is a potent vasoconstrictor and causes aldosterone secretion from the adrenal glands
aldosterone stimulates water and sodium resorption
Result: increased blood volume, increased preload, increased blood pressure
ACE inhibitors mechanism
ACE mediates the production of angiotensin 2
angiotensin 2 is a vasoconstrictor
angiotensin 2 mediates hypertrophy
angiotensin 2 also causes sodium and fluid retention
ACE inhibitors prevent the production of angiotensin 2
ACEIs mechanism
dilate blood vessels and reduce peripheral resistance
reduction in blood pressure
ACEIs reduce blood volume by preventing sodium and water retention
reduces preload and cardiac output
Indications for ACE inhibitors
- hypertension
- heart failure
- slow progression of left ventricular hypertrophy after MI
- renal protective effects in patients with diabetes
- drugs of choice in hypertensive patients with heart failure
- drugs of choice for diabetic patients
ACE inhibitors end in:
-pril
Adverse effects of ACE inhibitors
- fatigue
- dizziness
- headache
- mood changes
- impaired taste
- possible hyperkalemia
- dry cough
- angioedema
ACEIs inhibit the degradation of what?
bradykinin and substance P
bradykini is a vasodilator
but bradykinin and supstance P are responsible for the dry cough
contraindications of ACE inhibitors
known allergy high baseline potassium lactating women children bilateral renal artery stenosis can cause injury and death to the developing fetus
interactions of ACE inhibitors
NSAIDs can reduce the antihypertensive effects of the ACE inhibitors
may also predispose the patient to renal failure
concurrent use with lithium can cause lithium toxicity
potassium supplements can result in hyperkalemia
Angiotensin receptor blockers
newer class well tolerated have no effect on bradykinin metabolism so does not cause a dry cough
angiotensin 2 receptor blockers mechnism of action
primarily affect vascular smooth muscle and the adrenal gland
allows angiotensin 1 to be converted to angiotensin 2, but block the receptors that receive angiotensin 2
blocks vasoconstriction and the release of aldosterone
ARBs are better tolerated than ACE inhibitors in treating heart failure or in protecting the kidneys : as in diabetes
angiotensin 2 receptor blockers end in
-sartan
angiotensin 2 receptor blockers indications
hypertension
adjunctive drugs for the treatment of heart failure
may be used alone or with other drugs auch as diuretics
used primarily in patients who cannot tolerate ACE inhibitors
adverse effects of angiotensin 2 receptor blockers
- upper respiratory infections
- headache
- may cause occasional dizziness, inability to sleep, diahrrhea, dyspnea, heartburn, nasal congestion, back pain, fatigue,
- hyperkalemia is much less likely to occur
angiotensin 2 receptor blockers: contraindications
- known allergy
- pregnancy
- lactation
- use caution in the elderly with renal dysfunction
angiotensin 2 receptor blockers: interactions
- may promote hyperkalemia
- NSAIDs decrease ARB effects
- Lithium concurrent use with ARBs causes toxicity
- Rifampin decreased ARB effects
calcium channel blockers mechanism of action
smooth muscle relaxation by blocking the binding of calcium to its receptors
- decreased peripheral smooth muscle tone
- decreased systemic vascular resistance
- decreased blood pressure
calcium channel blockers end in
-ipine
calcium channel blockers indicators
-angina
-hypertension
-dysrhythmias
-migraine
-raynauds disease
carebral artery vasospasm
adverse effects of calcium channel blockers
cardiovascular: hypotension, palpitations, tachycardia, bradycardia
gastrointestinal: constipation and nausea
other: rash, flushing, peripheral edema, dermatitis, fatigue, headache, dizziness, dyspnea
rare: gingival hyperplasia
calcium channel blockers contraindications
known allergy
acute MI
second or hird degree block
hypotension
diuretics
act on the nephron in different ways to increase urine output
decrease plasma and extracellular fluid volumes
decrease preload
decrease cardiac output
decreased total peripheral resistance
overall effect: decreased workload of the heart, decreased blood pressure
diuretics end in
-azide
adverse drug reactions to diuretics
known allergy fluid and electrolyte disturbance nausea skin rashes photosensitivity thrombocytopenia pancreatitis cholecystitis
contraindications to diuretics
known allergy
hepatic coma
anuria
severe renal failure
vasodilators mechanism
directly relax smooth muscle do not work through adrenergic receptors results in: decreased systemic vascular response decreased afterload peripheral vasodilation
examples of vasodilators
diazoxide
hydralazine
minoxidil
sodium nitroprusside
vasodilators: indications
treatment of hypertension
may be used in combination with other drugs
sodium nitroprusside and intravenous diazoxide are reserved for the management of hypertensive emergencies
adverse effects of vasodilators
hydralazine: dizziness, headache, anxiety, tachycardia, nausea and vomiting, diarrhea, anemia, dyspnea, edema, nasal congestion, others
sodium nitroprusside: bradycardia, hypotension, possible cyanide toxicity
diazoxide: dizziness
contraindications of vasodilators
known allergy hypotension cerbral edema head injury acute MI CAD HF secondary to diastolic dysfunction
