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41 Cards in this Set
- Front
- Back
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Explain stage 1 hypertension |
Clinic blood pressure is 140/90 mmHg or higher and subsequent ambulatory blood pressure monitoring (ABPM) daytime average or home blood pressure monitoring (HBPM) average blood pressure is 135/85 mmHg or higher
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Explain stage 2 hypertension |
Clinic blood pressure is 160/100 mmHg or higher and subsequent ABPMdaytime average or HBPM average blood pressure is 150/95 mmHg or higher.
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Explain severe hypertension |
: Clinic systolic blood pressure is 180 mmHg or higher, or clinic diastolic blood pressure is 110 mmHg or higher.
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what are the possible causes of hypertension? |
• Volume of water in the body
• Levels of various hormones • Salt content of the body • Condition of the kidneys/CNS/blood vessels • 'White-coat' hypertension – those patients whose blood pressure rises to mildly hypertensive levels when a doctor appears with a cuff to take a reading! |
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what are the risk factors of hypertension? |
• A hereditary history of hypertension
• Sex (males may have a higher risk) • High plasma cholesterol • Obesity • Chronic stress • Cigarette smoking |
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what is the physical characteristic of hypertensive heart? |
Hypertension significantly increases the heart workload, and the left ventricle gradually enlarges – left ventricular hypertrophy.
The increased muscle mass has a greater O2 demand, and when the coronary circulation cannot keep pace ischaemia may occur leading to myocardial infarction. |
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Hypertension increases arterial pressures. Why is it dangerous? |
Increased arterial pressures place a physical stress on the walls of blood vessels throughout the body. This promotes the development of arteriosclerosis, and haemorrhages and aneurysms may occur. Vessels supplying the retina are often affected, and the circulatory changes often produce disturbances in vision.
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what are the symptoms of hypertension? |
The most insidious aspect of hypertension is that there may be no obvious symptoms, and often clinical problems do not appear until considerable damage has been caused.
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In what occasion is anti-hypertensive drug offered? |
1. Individuals aged <80 years with stage 1 hypertension who have target organ damage, established cardiovascular disease, renal disease, diabetes or a 10-year cardiovascular risk equivalent to 20% or greater.
2. To people of any age with stage 2 hypertension.For people aged <40 years with stage 1 hypertension and no evidence of target organ damage, cardiovascular disease, renal disease or diabetes, specialist evaluation of secondary causes of hypertension is undertaken |
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what are the general lifestyle advice for hypertension? |
● Ask people about their diet and exercise patterns, and offer guidance and written or audiovisualmaterials to promote lifestyle changes, e.g. doing more exercise.
● Alcohol consumption: encourage them to cut down if they drink excessively. ● Discourage excessive consumption of coffee and other caffeine-rich products. ● Encourage people to keep their salt intake low. ● Offer people who smoke advice and help to stop smoking. ● Relaxation therapies can reduce blood pressure and people may wish to try them. |
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How is cardiac output (CO) depending on? |
The cardiac output (CO) depends on the stroke volume (SV) and the heart rate (HR).
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what factors affecting stroke volume? |
The main factors affecting SV are the plasma volume and the venous return
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what are the drug classes of anti-hypertensive drugs available? |
- thiazide like diuretics - thiazide diuretics - beta-adrenoreceptor antagonists - ca+ channel antagonists - ACE inhibitors - AT1 receptor antagonists - alpha 1 adrenoreceptor antagonists - vasodilator drugs - centrally-acting drugs |
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give examples of thiazide like diuretics |
Chlortalidone indapamide |
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give examples of thiazide diuretics |
bendroflumetiazide |
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give examples of beta-adrenoreceptor antagonists |
propranolol atenolol metoprolol |
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give examples of Ca+ channel antagonists |
Calcium channel blockers; nifedipine amlodipine |
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give examples of Angiotensin converting enzyme inhibitors |
captopril enalapril |
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give examples of Angiotensin Ⅱ subtype 1 receptor antagonists |
ARB; losartan valsartan |
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give examples of alpha 1 adrenoreceptor antagonists |
prazosin terazosin |
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give examples of vasodilator drugs |
K+ channel activators (minoxidil) |
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give examples of centrally acting drugs |
alpha 2 adrenoreceptor agonists such as clonidine, methyldopa |
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According to NICE guideline, what is the step 1 of anti-hypertensive drugs? |
● For individuals <55 years of age, use an ACE inhibitor or a low-cost ARB. If an ACE inhibitor isprescribed and is not tolerated (e.g. dry cough) a low-cost ARB should be used.
● Individuals aged >55 years and black people of African or Caribbean family origin of any age, aCa2+-channel antagonist (CCB) is preferred. If a CCB is not suitable, for example because of oedema or intolerance, or if there is evidence of heart failure or a high risk of heart failure, a thiazide-like diuretic is suggested. ● If treatment with a diuretic is being started, or changed, offer a thiazide-like diuretic, such aschlortalidone or indapamide in preference to a conventional thiazide diuretic such as bendroflumethiazide or hydrochlorothiazide. ● For people who are already having treatment with bendroflumethiazide or hydrochlorothiazide and whose blood pressure is stable and well controlled, treatment should be continued. ● β-adrenoreceptor antagonists are not preferred in step 1. However, they may be considered for younger people if ACE inhibitors and ARBs are contraindicated or not tolerated or there is evidence of increased sympathetic drive, or for women of child-bearing potential. |
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what is the step 2? |
● CCB in combination with either an ACE inhibitor or an ARB.
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what is the step 3? |
● ACE inhibitor or an ARB in combination with a CCB and a thiazide-like diuretic.
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what are differences between thiazide and thiazide like diuretics |
Thiazide like diuretics act similaly to thiazide but do not contain the benzothiadiazine molecular structure. |
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what is the mechanisms of action of Thiazide/ thiazide like diuretics? |
Thiazides/thiazide-like diuretics are moderately potent, and inhibit the luminal membrane electroneural Na+/Cl- co-transport system found in the cortical diluting segment of the kidney distal convoluted tubule. These drugs also have some extra-renal actions - including vasodilation (possibly an effect on K+ channels in vascular smooth muscle). Initially, the fall in blood pressurewith these compounds is due to decreased blood volume resulting from diuresis, but the later phase seems to be due to a direct action on the blood vessels
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what are the side effects of thiazide/ thiazide like diuretics? |
Side effects: postural hypotension, impotence (reversible), hypokalaemia (low serum K+) and metabolic alkalosis (low serum H+) and rashes.
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what are the thiazide and thiazide like drug actions relevant to hypertension? |
• Increase in salt and water excretion via the kidney – lowers plasma volume
• Decrease in cardiac output via reduced plasma volume • Reduction in peripheral resistance |
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What are the stimulants of release of renin? |
1/ decreased blood flow through the kidney 2/ reduced Na+ concentration in the distal tubule 3/ stimulation of beta-adrenoreceptors |
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How does renin increase the BP? |
• The vasoconstrictor action of ATII (partly via augmentation of noradrenaline release)
• The aldosterone-mediated retention of salt and water, which leads to increased extracellular fluid volume. The raised plasma volume increases cardiac output. |
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How do ACE inhibitor work? |
ACE inhibitors: cause a fall in blood pressure, which is more marked in hypertensive individuals, especially when given together with diuretics. The drugs inhibit angiotensin converting enzyme (ACE), a carboxypeptidase enzyme that cleaves the c-terminal pair of amino acids from peptide substrates. ACE inhibitors lower blood pressure by preventing the conversion of angiotensin I to angiotensin II.
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what are ACE inhibitor actions relevant to hypertension? |
• Decreased ATII leads to decreased peripheral resistance
• Decreased aldosterone secretion leads to decreased salt/water retention • Decreased degradation of bradykinin leads to increased vasodilation • Sympathetic activity is lowered due to decreased noradrenaline release |
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what are the side effects of ACE inhibitors? |
ACEIs reduce both cardiac load and arterial pressure, but do not affect cardiac contractions, so cardiac output normally increases. A common side effect is a dry cough, possibly the result of an accumulation of bradykinin in the bronchial mucosa. Less common side effects include: diarrhoea, headache, loss of taste, nausea, tiredness, skin rash, joint pain.
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what are the contraindications of ACEI? |
should be avoided in pregnancy? |
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Who do angiotensin 2 receptor antagonists work? |
Losartan and valsartan are specific angiotensin II receptor antagonists (ARBs). However, unlike ACEinhibitors, they do not inhibit the breakdown of bradykinin and therefore do not cause the dry cough that complicates ace inhibitor therapy. They are therefore a useful alternative for patients who have to discontinue an ACE inhibitor for this reason.
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what are the side effects of ARBs? |
Side effects: are usually mild, but include hypotension. Contraindications: like ACEIs, ATII antagonists should be avoided in pregnancy.
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what are the mechanisms of beta-adorenoreceptor antagonists? |
(1) competitive antagonism of catecholamines at peripheral (especially cardiac) adrenergic sites, leading to decreased cardiac output, but also
(2) a central effect leading to reduced sympathetic outflow to the periphery, (3) suppression of renin release, which reduces the generation of angiotensin I and Ⅱ. This decreases ATII-induced vasoconstrictor activity and aldosterone-induced salt and water re-absorption |
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what are the side effects of beta-adorenoreceptor antagonists? |
it is no longer 1st line treatment: Side effects: bradycardia, hypotension, bronchospasm, fatigue, sleep disturbances |
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what are the contraindications of beta- adorenoreceptor antagonists? |
Contraindications: asthma, uncontrolled heart failure, Prinzmetal's angina.
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what are the beta-blocker actions relevant to hypertension? |
• Decrease in cardiac output
• Decrease in sympathetic activity by action in the CNS • Decrease of renin release, which reduces the generation of ATI and ATII |
