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80 Cards in this Set

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What is secondary HTN?
Hypertension has specific causes and high blood pressure is a result of another condition such as kidney disease or certain tumors.
What is primary or essential HTN?
HTN that has no identifiable cause. Drugs and lifestyle changes can control blood pressure.
What controls short term regulation of Blood pressure?
Baroreceptor reflexes in the aortic arch, carotid sinuses, and walls of vessels
What are the main goals of reducing blood pressure?
Reduce volume overload
Reduce sympathetic outflow from the brain
What are the ways to classify HTN treatment drugs?
1. Those that alter Na+/H2O balance (diuretics)
2. Sympathoplegic agents
3. Direct vasodilators
4. Agents that block production or action of angiotension
How do centrally acting drugs control BP?
They prevent sympathetic outflow from the brain by activating inhibitory alpha-2 receptors. They are used in mild to moderate HTN.
What is the MOA of methyldopa?
Causes a reduction in renal vascular resistance.
What are some adverse reactions of methyldopa?
Sedation, slight orthostatic hypotension, impotence, nightmares, and involuntary movements.
How does clonidine work?
Binds more tightly to alpha2 receptors than alpha1 receptors which results in reduction of cardiac output dur to reduced heart rate and relaxation of capacitance vessels.
Lowers HR and CO more than methyldopa.
What drugs may have the same MOA as clonidine?
Guanabenz and Guanfacine
What are some examples of peripheral acting drugs?
Reserpine, guanethidine, and guanedrel
How do peripheral acting drugs work?
They prevent norepinephrine release from peripheral nerve terminals (those that terminate on the heart)
These drugs do not enter the CNS or BBB, they work locally by collecting in the nerves. Therefore it takes 2 weeks to get maximum effects.
PS-these drugs are seldom used
What are the toxicities of reserpine?
Postural hypotension, diarrhea, and impared ejaculation
What are some Ganglionic-blocking drugs?
Mecamifamine and trimethaphan
How do ganglionic-blocking agents work?
These drugs competively block nicotinic cholinoceptors at autonomic sympathetic and parasympathetic ganglia.
No longer available because of intolerable Adverse reactions.
What was the first beta-blocker found to be effective in HTN?
Propranolol
How does propranolol work?
Non-selective block of beta-receptors.
Decreases primarily as a result of decrease in cardiac output but also inhibits the stimulation of renin production by catecholamines mediated by Beta1 receptors.
Produces significant decrease in BP without prominent orthostatic hypotension.
What are some "cardioselective" beta-blockers (B1 > B2)?
Metoprolol, atenolol, betaxolol, bisoprolol.
These can be used in patients with asthma, diabetes, and peripheral vascular disease.
What are some mixed alpha and beta antagonists?
Labetalol and carvedilol
(Labetalol is more of emergency situations)
What are some partial adrenergic agonists?
Pindolol, acebutolol, and penbutolol
What are the toxicities of beta-blockers?
Fatigue, sleep disturbance, depression, cardiac arrhythmias, and bronchoconstriction.
How does prazosin work?
It produces antihypertensive effects by blocking alpha1 receptors in arterioles and venules. Reduces arterial pressure by dilating both resistance and capacitance vessels.
Best used in combo with other agents such as beta-blockers and diuretics.
What are some toxicities of alpha-blockers?
Salt and water retention, dizziness, palpitations, HA, and lassitude
How do vasodilators work?
They relax smooth muscle of arterioles by decreasing systemic vascualar resistance. They do not cause orthostatic hypotension or sexual dysfunction.
What are some characteristics of hydralazine?
Dilates arterioles BUT not veins.
Used more effectively in severe HTN with combination of beta-blockers.
Very well absorbed but metabolized in first pass.
High doses resemble lupus erythematosis.
How does Minoxidil work?
Effects by opening of K+ channels in smooth muscle membranes by minoxidil sulfate.
Dilates arterioles but not veins. Must be used in combo with a beta-blocker and a loop diuretic.
May be given to patients with renal failure and severe HTN who don't respond to hydralizine.
What vasodilator is used in topical form for hair growth?
Minoxidil
How does Sodium Nitroprusside work?
Dilates both arterioles and venous vessels.
Breaks down in blood and releases NO which enters the muscle cells in blood vessel walls and causes relaxation.
Used IV to rapidly lower BP
What are some precautions of Sodium Nitroprusside?
Infusion solution is sensitive to light.
Serious cyanide toxicity can occur if not used properly-metabolic acidosis, arrhythmias, death
How does Diazoxide work?
It prevents vascular smooth muscle contraction by opening K+ channels and stabilizing the membrane potential at resting level.
What are some characteristics of Diazoxide?
Chemically similiar to thiazide diuretics but no diuretic action.
Inhibits insulin release from pancreas.
Causes renal salt and water retention.
Drug only used for short time in hospitals so side effects are not a problem
What is fenoldopam used for?
It is used in HTN emergencies.
It works by antagonizing dopamine D1 receptors which dilates peripheral arteries and causes water and salt secretion.
What are toxicities of fenoldopam?
Can increase intracellular pressure.
Same toxicities as other vasodilators---(reflex tachycardia, HA, flushing)
What are some Ca+ channel blockers?
Dihyropyridines
Verapamil and Diltiazem
They act by inhibition of Ca++ influx into arterial SMC
Which Ca++ blockers are more selective vasodilators with less cardiodepression?
Dihydropyridines
What are some Dihydropyridines?
Amlodipine, nicardipine, felodipine, nifedipine.....
What drug has alpha-adrenergic blocking activities and has more cardiac effect, decreases cardiac output.
Verapamil or Diltiazem?
Verapamil
Describe the different types of angina.
1. Stable Angina - plaque causes reduced vessel lumen size and blood flow is decreased
2. Unstable angina - platelet aggregation and vasoconstriction
3. Variant Angina - Inconsistent vasospasm occurs sponataneously
A general term that refers to a number of diseases other than artherosclerosis, which causes a narrowing of the major epicardial coronary arteries.
Coronary Artery Disease
Most common form of angina, the result of a fixed obstruction. Treatment involves rest, nitro, or both.
Stable Angina
Angina caused by significant coronary artery disease.
Treatment involves rest and nitro
Unstable Angina
Angina involving a coronary artery spasm that reduces blood flow. The spasm is reversible. Usually occurs during rest and pain may distrub sleep. Treat with Ca++ channel or beta-blocker.
Nitro will not provide relief.
Variant or vasospastic Angina
What are the 3 drug groups used to treat angina?
Organic nitrates, Ca++ channel blockers, and beta-blockers
How do anti-anginal durgs work?
They decrease myocardial oxygen requirement by decreasing the determinants of oxygen demand.
What are some examples of nitrates and nitrites?
Nitroglycerin, isosorbide dinitrate, and amyl nitrate
How do nitrovasodilators work?
They relax most smooth muscle, including arteries and veins.
The reactive free radical (NO) activates guanylyl cyclase and increases the synthesis of cyclic GMP in smooth muscle and other tissues.
What are the organ system effects of nitrates or nitrites?
Veins respond at the lowest concentration than arteries by increasing venous capacitance and decreased ventricular preload.
Toxicities include: throbbing HA and orthostatic hypotension.
Indirectly causes tachycardia and increases cardiac contractility.
What are the effects of nitrates on other smooth muscle cells?
Relax smooth muscle of bronchi, GI tract, (no clinical value)
Inhalation nitrates used as "sex enhancers"
How does cyanide react with the body?
Cyanide ions bind to the ion of the enzyme C oxidase in the mitochondrial membrane of cells and this results in cytotoxic hypoxia.
What is used to treat cyandie poisoning?
Sodium nitrate is administered soon after cyanide exposure because this will cause conversion to methemoglobin which has a high affinity for CN-. Further administration of sodium thiosulfate results in the complex formation of thiocyanate which is excreted by the kidneys.
How do Ca++ channel blockers work?
By blocking Ca++ channels, drugs decrease contraction of the heart and dilate the arteries.
What Ca++ channels are therapeutically useful to block?
L-type channels found in muscles and neurons.
What are the kinetics of Ca++ channel blockers?
Orally effective, high first pass metabolism, high plasma protein binding, extensive metabolism
What is the MOA for Ca++ channel blockers?
They act on the inner side of the membrane and bind more effectively to channels in depolarized membranes. They decrease Ca++ currents, which result in long-term smooth muscle relaxation. Reduces cardiac contractility.
What are the effects of Ca++ channel blockers on other organ systems?
1. Smooth muscle - normal resting tone and contractile response. Arterioles are more sensitive than veins and arteries.
2. Cardiac muslce - decreases impulse generation in the SA node, decreased conduction in the AV node.
3. No important effect on skeletal muscle
4. Cerebral vasospasm - nimodipine is used in patients with hemorrhagic stroke
5. Other effects - shown to block P170 glycoprotein responsible for trasnport of drugs out of cancer cells.
What are the toxicities of Ca++ blockers?
Serious cardiac depression.
Increase MI in patients with HTN
Concurrent use with beta-blockers, increase cardio-depressant activity.
Minor effects - flushing, constipation, dizziness, peripheral edema
How are Ca++ blockers used in angina?
Relieves vasospasm in variant angina.
In classic angina, they reduce myocardial O2 demand as a result of hemodynamic effects on heart.
How do beta-blockers help treat angina?
Beta-blockers decrease myocardial O2 requirements at rest and during exercise. Reduces total amount of "ishemic time" per day. Better outcomes in patients with stable angina.
What are some characteristics of timolol?
Non-selective beta-blocker in oral form.
Toxicities are arrhythmias, bronchospasm, heart failure, depression, and impotence.
Why does heart failure occur?
Heart failure occurs when the heart can no longer pump enough blood to meet the metabolic demands of the body.
What are the risk factors for heart failure?
Smoking, HTN, and high fat diet.
What are the sites of action for drugs used to treat heart failure?
1. Na+/K+ ATPase pump
2. Na/Ca++ exchanger channel
3. Selective Ca++ channel
4. Ca+ transporter on SR that pumps into SR
5. Channel that leads stored Ca++ in SR to the cytoplasm
Calcium concentrations are highest in the cytoplasm of a cell. True or False?
False
How does the heart try to compensate for low blood flow in heart failure?
The heart uses hormones to create water retention in the kidney to retain water.
What are some symptoms of heart failure?
Tachycardia, decreased exercise tolerance, shortness of breath, peripheral adn pulmonary edema, cardiomegaly
How is heart failure classified?
1. The side of the heart involved.
2. Whether the abnormality is due to contractility or relaxation of heart (problems with ventricular filling)
3. Whether the abnormality is due to low cardiac output or low systemic vascular resistance
What are the 4 classes of heart failure?
Class I - symptoms occur at extraordinary levels of excretion
Class II - slight limiations on ordinary activity
Class III - symptoms at less than ordinary activity
Class IV - symptoms present at rest
What are the 4 primary factors of cardiac performance?
Preload, afterload, contractility, and heart rate
What are the kinetics of digitalis?
Well-absorbed oral adminnistration, wide distribution, not extensively metabolized (2/3 drug in urine)
What are the mechanical effects of digitalis?
1. Cardiac glycosides inhibit Na+/K+ ATPase which increases intracellular Na+
2. Because intracellular Na+ increases, Ca++ expulsion is reduced which increases intracellular Ca++
3. With more Ca++ present, the intensity of the interaction of contractile proteins increases
What are the direct and autonomic actions of digitalis?
Direct actions - shortening of atria and ventricular refactoriness
In low dose: parasympathomimetic effects predominate
In High dose: increased sympathetic outflow
What are the effects of digitalis on other organs beside the heart?
Increase spontaneous activity in neurons and SMC
-GI tract: anorexia, nausea, vomitting, diarrhea
-CNS: disorientation, hallucinations, visual disturbances
Gynecomastia in males
How do ions effect the digitalis effects?>
Potassium: inhibits binding of digitalis to Na+/K+ ATPase
Calcium: hypercalcemia increases risk of arrhythmias
Magnesium: hypo-magnesemia increases risk of arrhythmias
It is important to monitor electrolytes
What are the classes of inotropic drugs besides digitalis?
1. Phosphodiesterase inhibitors
2. Beta-adrenoceptor stimulants
How do inamrinone and milrinnone work?
They are PDE inhibitors that decrease both preload and afterload. Not used long-term.
What are the toxicities of PDE inhibitors?
Nausea, vomitting, arrhythmias, thrombocytopenia.
These drugs are used infrequently because of these toxicities
How do beta-adrenoceptor stimulants work?
Increase contractility and decrease afterload
How does dobutamine work?
Increase in cardiac output together with a decrease in ventricular pressure.
How does dopamine work for heart failure?
Dopamine is a beta1-selective agonist and beta2 effect on skeletal muscle.
Side effect is tachycardia
What are the drug classes without inotropic effects that are used for heart failure?
1. Diuretics
2. Vasodilators
3. Beta-adrenoceptor blockers
4. Angiotensin receptor antagonist