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> most common CVS disease
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> elevated arterial BP damages vessels in renal, heart and brain
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Complications:
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Renal failure, Coronary disease, Heart failure, Stroke, Diamentia
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Classification:
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Systolic BP
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Diastolic BP:
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Normal:
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<120
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<80
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Pre-hypertension:
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120-139
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80-89
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Stage 1 HTN:
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140-159
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90-99
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Stage 2 HTN:
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>= 160
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>=100
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Essential Hypertension (85-90%):
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Primary hypertension, no identifiable cause (genetic), can't be cured, can be controlled
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Secondary Hypertension (10-15%):
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Specific identified cause (comorbid disease or drug), can be cured when cause is eliminated
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> Genetic factors
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> Psychological stress
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> Environmental and Dietary Factors:
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high salt diet, decreased calcium and phosphate intake, sedentary lifestyle
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> Diseases:
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renal, endocrine, vascular, renal diseases
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> Drugs:
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sympathomimetic amines, amphetamines, oral decongestants (eg. pseudoehedrine), corticosteroids, osteogens (C0Cs), NSAIDs, COX-2 inhibitors
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- Often incidental finding
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- Adults should get BP checks once a year
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- Severe cases:
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Headaches, visual disturbances, target organ damage (stroke, ischemic heart disease, renal failure)
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BP= CO x PVR
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Increased Cardiac output:
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Increased fluid volume from excessive sodium intake or renal sodium retention Venous constriction: due to excess stimulation of RAAS
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Increased Peripheral resistance:
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Excess stimulation of RAAS Sympathetic nervous system over-activity
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> Diuretics:
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Reduce blood volume=Depletes the body of sodium, Venodilation
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> Sympathoplegic agents:
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Reduce peripheral vascular resistance, Inhibit cardiac function, Increase venous pooling capacitance vessels
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> Direct vasodilators:
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Reduce peripheral vascular resistance, Increase venous pooling capacitance vessels
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> Angiotensin antagonists:
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Reduce peripheral vascular resistance, Reduce blood volume
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- Reduce blood volume and cardiac output
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- Cardiac output returns to normal
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But peripheral vascular resistance declines
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- Sodium
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Contributes to vascular resistance = Increase vessel stiffness
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- Venodilation
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Altered sodium-sodium calcium exchange
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> Lower BP by 10-15 mmHg in most patients
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> Thiazide diuretics –mild to moderate HTN
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> Loop diuretics – severe HTN and hypertensive emergencies
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Centrally-acting Drugs:
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Methyldopa, clonidine
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Adrenoceptor antagonists
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Beta-blockers, alpha-1 blockers
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Ganglionic-blocking Agents:
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No longer used clinically ; hexamethonium
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Adrenergic neuron blocking agents:
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Block the release of noradrenaline, Reserpine, guanethidine, debrisoquin, Not/rarely used clinically
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- Methyldopa, clonidine
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rarely used except clondine
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- Reduces sympathetic outflow
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- Compensatory response mechanism:
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salt retention
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- Clonidine, guanabenz, guanfacine
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Stimulate central alpha-2 adrenoceptors
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- Methyldopa – anologue of L-dopa
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Results in the synthesis of a false neurotransmitter
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Alpha-methylnoradrenaline = Stimulates central alpha-2 adrenoceptors
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Non-selective: Propranolol
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Beta-1 selective: “BBEAM”
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Betaxolol, bisoprolol, esoprolol, atenolol, metoprolol, Cardioselective
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Vasodilator beta-blockers
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Also block alpha-1 receptors,Labetolol, carvidelol, nebivolol
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Prazosin, terazosin, doxazosin
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Block alpha-1 receptors in arterioles and veins
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Vasodilation
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Reduce peripheral resistance
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Compensatory mechanism:
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salt and water retention
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> Dihydropyridines
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amlodipine, isradipine, nicardipine, nimodipine, felodipine, nisoldipine, lacidipine
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> Non-dihydropyridines
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Verapamil, diltiazem, hydralazine
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Benzothiazepine (diltiazem)
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Dihydropyridine CCBs
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Primary vasodilators (reduce PVR), All decrease cardiac contractility except amlodipine and felodipine
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Non-dihydropyridines (diltiazem, verapamil)
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directly block the AV node, decrease heart rate,decrease cardiac contraction
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Adverse effects:
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1. Flushing, peripheral oedema, tachycardia, bradycardia, heartblock
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Angiotensin converting enzyme inhibitors (ACEIs)
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Captopril, enalapril, Ramipril, fosinopril, trandopril
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Angiotensin receptor blockers (ARBs)
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Losartan, valsartan, telmisartan, irbesartan, candesartan
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Renin-inhibitors
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Aliskiren
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