Cardiovascular Drugs
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- Thiazide diuretics: What drugs?
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Chlorothazide
Hydrochlorothiazide - Thiazide diuretics: effects?
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decrease plasma volume (PV)
decrease venous return, which causes a decrease in cardiac output (CO)
cardiopulmonary reflexes respond to decreased BP due to decreased PV
reflexes causes:
increased peripheral resistance
increased heart rate
increased plasma renin levels
decrease systemic vascular resistance w/ chronic use which balances the CV reflex reaction - Thiazide diuretics: mechanism of action?
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increase sodium and water excretion by inhibiting reabsorption of sodium and chloride ions in the distal nephron
relaxation of vascular smooth muscle w/ chronic use - Thiazide diurectics: therapeutic uses?
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used alone to control BP in Stage 1 & Stage 2 HT
Combined w/ other anti-HT drugs to control fluid
retention and edema caused by the other drug - Thiazide diuretics: adverse effects?
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muscle weakness
fatigue
Potassium loss: leads to muscle crams and cardiac arrythmias
hyperglycemia (problem only in diabetics)
increased total cholesterol due to increased VLDL
impotence
also, metabolic acidosis, hyponatremia, volume depletion, and hyperuricemia - Potassium sparing diuretics: what drugs?
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spironolactone
triamterene
amiloride - Potassium sparing diuretics: effects?
- decrease potassium loss
- Potassium sparing diuretics: therapeutic use?
- used in combination w/ thiazide and loop diuretics to decrease potassium
- Loop diuretics: effects?
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decrease fluid retention
decrease peripheral vascular resistance - Loop diuretics: therapeutic use?
- used in combination w/ anti-HT drugs which cause pronounced fluid retention
- B-adrenergic receptor blockers: what drugs?
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propranolol(non-selective, B1 & B2)
nadolol(non-selective, B1 & B2)
metoprolol(cardioselective, B1 only)
atenolol(cardioselective, B1 only)
pindolol(non-cardioselective)
labetalol(non-cardioselective) - B-blocker: effects?
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B-1 receptor block
decrease in HR
decrease in contractility
B-2 receptor block
decrease norepinephrine release
Non-selective B block
in addition to previous affects:
increase total cholesterol
increase LDL
decrease HDL - B-blocker: mechanism of action?
- B-2 receptor block: blocks presynaptic B-2 receptors that mediate a feedback facilitation of norepinephrine release, leaving A-2 receptor mediated inhibition of norepinephrine release unopposed
- Labetalol (B-blocker): effects?
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decreases peripheral vascular resistance
HR is not decreased - Labetalol: mechanism of action?
- blocks B-receptors and A-receptors
- Calcium channel blockers: what drugs?
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nifedipine (dihydropyridine)
verapamil (non-dihydropyridine)
diltiazem (non-dihydropyridine) - Calcium channel blockers: effect?
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decrease cardiac automaticity
decrease AV conduction
decrease cardiac contractility
dihydropyridines have a greater effect on blood vessels
non-dyhydropyridines have a greater effect on the heart
vasodilation - Calcium channel blockers: mechanism of action?
- blocks L-type calcium channels: channels responsible for the generation of action potentials in vascular smooth muscle
- Calcium channel blockers: therapeutic use?
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used alone in therapy of Stage 1, 2, & 3 HT
used in combination w/ a thiazide diuretic or an ACE-inhibitor in therapy of stages of HT - Calcium channel blockers: adverse effects?
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Dihydropyridines
headache
tachycardia
digital dysesthesia
ankle edema
Non-dihydropyridines
bradycardia
constipation
Contraindicated in pts. with ejection fraction less than 30%, sinus bradycardia, atrial ventricular conduction disturbances - Angiotensin Converting Enzyme (ACE) Inhibitors: what drugs?
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Captopril
Enalapril
Lisinopril - ACE Inhibitors: effects?
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decrease angiotensin II
decrease aldosterone
decrease BP
decrease cardiac preload and cardiac afterload - ACE Inhibitors: mechanism of action?
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prevents the conversion of angiotensin I to angiotensin to by inhibiting angiotensin converting enzyme
prevent the enzymatic inactivation of bradykinin - ACE Inhibitors: therapeutic use?
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used alone in the treatment of Stage 1, 2, & 3 HT
used in combination w/ thiazide diuretics, calcium channel blockers, or b-blockers in the therapy of Stage 4 HT - ACE Inhibitors: adverse effects?
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severe hypotension w/ 1st dose
dry cough
hyperkalemia
dysgeusia (loss of taste sensation)
maculopapular rasch
angioedema
Can cause fetal mortality in 2nd and 3rd trimesters - Angiotensin receptor blocking agent: what drugs?
- Losartan
- Losartan: effects?
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decreases preload
decreases afterload - Losartan: mechanism of action?
- competitive inhibitor of angiotensin II on the angiotensin 1 (AT-1) receptor
- Losartan: therapeutic use?
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used alone for Stage 1, 2, & 3
used in combo w/ thiazide diuretics, calcium channel blockers, & B-blockers in therapy for Stage 4 HT - Losartan: adverse effects?
- dizziness
- Alpha adrenergic blockers: what drugs?
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Prazosin
Terazosin - A-blockers: effect?
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decreases preload (venous dilation)
decreases afterload (arterial dilation) - A-blockers: mechanism of action?
- blocks A-1 receptor
- A-blockers: therapeutic use?
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used alone for Stage 1 HT
used w/ a diuretic for Stage 2 HT - A-blockers: adverse effects
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prazosin
postural hypotension w/ first dose (first doese effect) due to venous vasodilation
dizziness
headache
tachycardia
delayed ejaculation
incontinence
orthostatic hypotension
nasal stuffiness - Centrally acting drugs: what drugs?
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Clonidine
Methyldopa
Guanabenz
Guanfacine - Centrally acting drugs: effect?
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Clonidine
decrease sympathetic activity
increase parasympathetic activity
decrease norepinephrine release
decrease peripheral vascular resistance
decrease cardiac output - Centrally acting drugs: mechanism of action?
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Clonidine
stimulate central A-2 receptors
stimulate peripheral presynaptic A-2 receptors
Methyldopa
converted by enzymes DOPA decarboxylase and dopamine-B-hydroxylase to a-methylnorepinephrine which is stored in synaptic vesicle s and released in response to nerve activity
stimulates central and peripheral A-2 receptors - Centrally acting drugs: therapeutic use?
- used in combo w/ diuretics for all Stages of HT
- Centrally acting drugs: adverse effects?
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sedation
dry mouth
bradycardia
constipation
Rebound hypertension upon abrupt withdrawal(dramatic rise in HR and BP, profuse sweating)
methyl dopa specific effects
decreased liver function
positive Coomb's test
mental lassitude
impaired concentration - Peripheral adrenergic blockers: what drugs?
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Reserpine
Guanethidine - Peripheral adrenergic blockers: effect?
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decreased cardiac preload
decreased cardiac afterload - Peripheral adrenergic blockers: mechanism of action?
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Reserpine
interferes w/ the transport of norepinephrine and dopamine from the cytosol into synaptic vesicles - Peripheral adrenergic blockers: therapeutic use?
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Reserpine
use w/ a diuretic for all Stages of HT
Guanethidine
severe HT - Peripheral adrenergic blockers: adverse effects?
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Reserpine
Psychic depression
sedation
inability to concentrate
bradycardia
orthostatic hypotension
nausea
diarrhea
nasal congestion
delayed ejaculation
attenuation of sexual orgasm