7: Antihypertensive (Angina, Arrhythmias, CHF) Flashcards
equation for blood pressure
BP = CO x TPR
what is the function of the baroreceptor reflex?
to monitor and correct changes in BP within seconds by altering cardiac output and peripheral vascular resistance
how do kidneys help with long term management of BP?
they control fluid balance
which type of hypertension is less common?
secondary hypertension (<10%)
which type of hypertension means there is no clear cause of the elevated BP?
primary hypertension
what are some causes of secondary hypertension?
chronic kidney disease, renal artery stenosis, endocrine disorders
how is secondary hypertension treated?
treatment focuses on correcting the abnormality –find the cause and address it specifically
what are possible causes of primary hypertension?
diet, stress, genetics, cigarette smoking, alcohol abuse, obesity
how are peripheral vessels impacted by consistently high BP?
vessels become less compliant and resistance increases
what are metabolic abnormalities associated with hypertension?
insulin resistance (impaired glucose metabolism), hyperinsulinemia, dyslipidemia, abdominal obesity (these characteristics all together are known as metabolic syndrome)
what classes of drugs are used to treat HTN?
diuretics
sympatholytics
vasodilators
renin-angiotensin inhibitors
calcium-channel blockers
what is the mechanism of diuretics?
they increase renal excretion of water and sodium, which decreases fluid volume in the vascular system
why do pts need a potassium supplements when taking diuretics?
potassium is also decreased with diuretics, which can lead to arrhythmias, decreased energy, and inability to tolerate PT
what are three types of diuretics?
thiazide, loop, and potassium-sparing
what is required for using thiazide diuretics?
good kidney function (often not a good choice for geriatrics)
are loop diuretics more or less potent than thiazides?
more potent
what are adverse effects of diuretics?
fluid depletion, electrolyte imbalance, low sodium, low potassium, orthostatic hypotension, impaired glucose or lipid metabolism, tired, up all night peeing
what are problems caused by fluid depletion (with use of diuretics)?
decrease in blood volume, increase in CO and peripheral resistance due to activation of the baroreceptor reflex
What are examples of sympatholytics?
beta blockers
alpha blockers
presynaptic adrenergic inhibitors
centrally acting agonists
What are sympatholytics?
drugs that block or interfere with sympathetic discharge
how do beta adrenergic blockers address HTN?
decrease CO and myocardial force, which slow down HR
suffix of sympatholytic beta blockers
(-lol)
side effects of beta blockers
excessive HR depression, orthostatic hypotension, impaired glucose and lipid metabolism, depression, fatigue, GI disturbances, allergic reactions, blunted HR response with exercise
what is the mechanism of alpha blockers?
they block alpha-1 adrenergic receptors on vascular smooth muscle, which decreases vascular resistance
adverse effects of alpha blockers
reflex tachycardia, orthostatic hypotension, increase in cardiac disease and CHF
what is reflex tachycardia?
when peripheral vascular resistance fails, the baroreceptor reflex may kick in and cause a compensatory increase in HR
why do alpha blockers increase risk of cardiac disease and CHF?
they allow vasodilation, which increases plasma volume and increases the workload of the heart (if they have a known risk of any cardiac disease, they should avoid alpha blockers)
what is the mechanism of presynaptic adrenergic inhibitors?
they inhibit the release of norepinephrine from the presynaptic terminals, which decreases sympathy excitation of the heart and vasculature, resulting in decreased BP
what is the mechanism of presynaptic adrenergic inhibitors?
they inhibit the release of norepinephrine from the presynaptic terminals, which decreases sympathy excitation of the heart and vasculature, resulting in decreased BP
what are adverse effects of alpha blockers?
bradycardia, arrhythmias, drowsiness, GI disturbances (nausea, vomiting, diarrhea)