Anti-hypertensives Flashcards
How do diuretics work?
reduce blood pressure by depleting the body of sodium and decreasing blood volume
How do sympathoplegic agents work?
lower blood pressure by inhibiting the function of the sympathetic nervous system. As a result, they reduce PVR, inhibit cardiac function (which reduces CO), and increases venous pooling in capacitance vessels (which reduces CO)
How do vasodilators work?
reduce blood pressure by relaxing vascular smooth muscle; this leads to dilating vessels and increasing capacitance
How do inhibitors of angiotensin work?
lower blood pressure by inihibiting the renin-angiotensin-aldosterone pathway in the kidneys. As a result, they reduce PVR and blood volume
Sodium contributes to PVR by (increasing or decreasing?) vessel stiffness and neural activity?
increasing
Increasing vessel stiffness by sodium leads to ______
an increase in intracellular calcium
What drugs are used in combination with diuretics in patients with severe hypertension?
sympathoplegic and vasodilator drugs
What do sympathoplegic drugs inhibit the function of?
the sympathetic nervous system
What happens if you use a sympathplegic drug alone?
may cause retention of sodium and water by the kidneys and expansion of blood volume (via the RAAS pathway)
Which drug type should be used in combination with a sympathoplegic drug to make its effects more beneficial?
diuretic
Name the central alpha-2 adrenergic agonists
Methyldopa
Clonidine
Guanabenz
Guanfacine
Where do the central alpha-2 adrenergic agonists act on?
the central sympathetic neurons in the brain
What is the MOA for the central alpha-2 adrenergic agonists?
Work on sympathetic neurons in the brain stimulating central alpha-adrenoceptors to reduce sympathetic outflow from vasopressor centers in the brain
Are toxicities dependent on posture?
no, because they work on central neurons
Name the adrenergic neuron-blocking agents
Reserpine
How do the adrenergic neuron-blocking agents work?
reduce blood pressure by preventing normal physiologic release of norepinephrine from prostaganglionic sympathetic neurons
Where is Reserpine derived from?
it is a natural alkaloid derived from the roots of the plant Rauwolfia serpentine
What Reserpine cause in higher doses?
severe depression
What is Reserpine’s MOA?
Binds irreversibly and blocks the uptake and storage of biogenic amines in throughout the body inhibiting the uptake mechanism that depends on Mg and ATP resulting in a depletion of NE, dopamine, and serotonin in BOTH central and peripheral neurons
Name the beta-adrenoceptor antagonists (beta-blocker) discussed in the notes
Propanolol
Nebivolol
Where does Beta-1 act on?
Heart
Brain
Kidney
Where does Beta-2 act on?
Heart
Smooth muscle
Liver
Where does Beta-3 act on?
Heart
Lipocytes
What are the toxicities for the central alpha-2 adrenergic agonists?
- Sedation
- Mental Depression
- Sleep disturbances (nightmares)
Name the toxicities of Reserpine
- Mild postural HTN
- Sedation
- Nightmares
- Mental depression
- Extrapyramidal effects resembling Parkinson’s as a result of dopamine depletion in the corpus striatum
Beta-blockers antagonize the effects of ________ at the Beta-adrenergic receptors
catecholamines
How does Propanolol work?
lower blood pressure by decreasing CO
Which beta-blocker exhibits nitric oxide-mediated vasodilating activity?
Nebivolol
Is Propanolol selective or non-selective? If selective, which beta-adrenergic subtype is selective to?
nonselective
Is Nebivolol selective or non-selective? If selective, which beta-adrenergic subtype is selective to?
Beta-1 selective
What is the beta-blockers MOA?
Blocks beta-1 and beta-2 receptors inhibiting the stimulation of renin production by the catecholamines
Name some toxicities of Propanolol
- Asthma
- Sedation
- Sleep disturbances
- Depression
- Caution in patients with bradycardia or cardiac conduction disease
- Bronchospasm (at very high doses, non-selective)
What can patients experience if they abruptly discontinue the use of beta-blocker therapy after chronic use/
withdrawal symptoms such as nervousness, tachycardia, HTN, and/or MI
Name the alpha-adrenoceptor antagonist discussed in the notes
Prazosin
Where does alpha-1 act on?
Heart
Smooth muscle
Prostate
Where does alpha-2 act on?
Lipocytes
Smooth muscle
Platelets
Is Prazosin selective or non-selective? If selective, which receptor subtype is selective towards?
alpha-1 selective
What is the MOA of alpha blockers?
Antagonizes (blocks) the effects of catecholamines causing dilation in BOTH resistance (arterioles) and capacitance (venules) vessels thus causing vasodilation thereby reducing BP
Which class of drugs are used in combination with alpha blockers to make them more effective?
Beta-blockers
Diuretics
Name the toxicities of Prazosin
Little postural hypotension (especially after the first dose)
First-dose phenomenon occurs in salt and volume depleted patients—first dose should be given at bedtime
True or False: Blood pressure is reduced more in the upright position?
True
Name the non-dihydropyridine CCBs
Verapamil
Diltiazem
Name the dihydropyrimidn CCBs discussed in the notes
Nifedipine
What is the MOA of the CCBs?
Block calcium channels in:
- Arteriole smooth muscle cells resulting in inhibition of calcium influx
- Cardiac muscle cells inhibiting calcium influx which will reduce contractility, decrease SA pacemaker rate and AV conduction
What is the function of CCBs?
dilate peripheral arterioles and reduce blood pressure
Which CCB is the more selective vasodilator and has a less cardiac depressant effect than the others?
Nifedipine
Which CCB has the greatest depressant effect?
Verapamil
Which CCB has intermediate effects?
Diltiazem
Name the oral vasodilator
Minoxidil
Name the parenteral vasodilators
Nitroprusside
Fenoldopam
Which type of vasodilator is used for long-term outpatient therapy?
oral vasodilators
Which type of vasodilator is used to treat hypertensive emergencies?
parenteral vasodilators
What is the function of vasodilators?
effective in treating HTN because they relax smooth muscle of arterioles, which leads to a decrease in systemic vascular resistance
Which vasodilator dilates both arterial and venous vessels, resulting in reduced PVR and venous return?
Sodium Nitroprusside
What is the MOA of Minoxidil?
Lowers BP by activating the ATP-modulated K channels opening them and allowing K efflux causing hyperpolarization making contraction less likely resulting in an overall relaxation of vascular smooth muscle