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123 Cards in this Set
- Front
- Back
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Name 2 classes of drugs used to treat hypertension in patients over 55yrs old
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1) calcium channel blockers
2) thiazide diuretics (thiazides) |
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Name two drugs used to treat hypertension in pts >55yrs old, and the class of drug
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1) calcium channel blockers (e.g. Nefidipine, Verapamil)
2) thiazide diuretics (bendroflumethiazide) |
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What are the 2 first line drugs for the Tx of hypertension in pts. less than 55yrs old and caucasian?
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1) ACE inhibitors (Ramipril)
2) Angiotensin II Receptor antagonist (Losartil) |
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How do loop and thiazide diuretics differ?
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Thiazide diuretics
- less potent than loop - used for hypertension - safer for long-term use Loop diuretics - more potent - used for heart failure |
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What is the action of a diuretic?
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Diuretics increase urine volume by reducing salt and water reabsorption from kidney tubules.
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Explain why oedema occurs.
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Oedema occurs when the rate of fluid formation exceeds the rate of fluid reabsorption from the interstitial fluid into the capillaries.
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What effects do loop diuretics have?
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- greatly increase excreted Sodium%
- potent diuretic - act on thick ascending loop of Henle - have venodilation action |
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What is the action of thiazide diuretics?
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Thiazide diuretics:
1. increase salt and water excretion (reduce extracellular fluid volume) 2. decrease cardiac output by reducing plasma vol. 3. reduce peripheral resistance 4. increase renin release |
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What different types of drug exist for Tx of hypertension?
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1- thiazide diuretics
2- ACE inhibitors 3- Angiotensin II receptor antagonists 4- Calcium channel blockers/antagonists 5- Beta-adrenoceptor antagonists |
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What system do antihypertensive drugs work on?
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The renin-angiotensin system
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What does the renin-angiotensin-aldosterone system do?
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regulates blood pressure and systemic vascular resistance
influences cardiac output and arterial pressure |
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What is the end product of the renin-angiotensin-aldosterone (RAAS) system?
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The final end product of the renin-angiotensin-aldosterone system is aldosterone, produced in the Adrenal glands and acts on the kidneys
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What action does Aldosterone have and on which organ?
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Aldosterone acts on the kidney to increase sodium absorption.
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What is NATURESIS?
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Naturesis is the excretion of sodium in the urine, esp. in greater than normal amounts.
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All diuretics increase _________ by increasing urine production and excretion of ______.
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All diuretics increase NATURESIS by increasing urine production and SODIUM excretion.
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Why might thiazide diuretics be used in preference to loop diuretics?
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1) less potent than loops
2) better tolerated than loops 3) reduce stroke and MI risk associated with hypertension 4) reduce calcium excretion (hence = bone preserving) |
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Name 3 indications for use of thiazide diuretics
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thiazide diuretics are indicated for:
1) uncomplicated hypertension 2) mild cardiac failure 3) resistant oedema + loop |
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Name two examples of thiazide diuretics
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examples of thiazide diuretics
1. Bendroflumethiazide 2. Indapamide |
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What is the mechanism of action of thiazide diuretics?
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Thiazide diuretics MOA:
a) mild diuresis b) inhibit reabsorption of sodium and chloride ions by distal convoluted tubule c) sodium is lost as urine d) decreased plasma volume & decreased peripheral resistance |
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Name 4 main adverse effects of thiazide diuretics
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Thiazide diuretics:
1. impair glucose tolerance 2. cause sodium deficiency 3. cause potassium deficiency 4. uric acid retention 5. allergy (rare) |
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Why would loop diuretics be used in Tx of hypertension?
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Loop diuretics might be used where:
- a more potent diuretic is needed - if hypertension is persistent - where heart failure is present |
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What are the main indications of loop diuretic use?
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Loop diuretic indications:
1) heart failure 2) hypertension if thiazides don't work 3) pulmonary oedema 4) refractory oedema |
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Name a loop diuretic
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Furosemide = loop diuretic
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What is the mechanism of action of loop diuretics?
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Loop diuretics MOA:
1. work on ASCENDING LIMB of Loop of Henle 2. stop chloride ion reabsorption 3. chloride and sodium ions are lost & water follows |
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Name three contraindications for thiazide diuretic use, and explain why:
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thiazide contraindications:
1. kidney failure (targets tubule) 2. diabetes mellitus (may cause hyperglycemia) 3. gout (decreases uric acid excretion) |
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How much sodium is normally excreted by the kidneys?
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normally about 1% of filtered sodium is excreted in the urine
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Describe the main sites of action of the loop and thiazide diuretics
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Loop diuretics act on thick segment of ascending loop (of Henle).
Thiazides act on proximal part of the distal convoluted tubule. |
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What is a "symport system"?
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A symport system is one in which the transport of one substance across a membrane is coupled to that of another. Both travel in the same direction.
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What is a NEPHRON?
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A nephron is made up of a glomerulus and its associated tubules.
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Name four substances not normally present in urine.
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Blood, glucose, acetone and proteins are not normally present in urine.
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Name four substances that are excreted by the kidneys.
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the kidneys excrete:
1. water 2. urates, uric acid, urea (protein metabolites) 3. salts (electrolytes) 4. drugs and toxins |
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Name some classes of salts excreted by the kidneys.
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Salts excreted by the kidneys include:
- chlorides - phosphates - sulphates of Na/K/Ca |
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What is the osmotic diuretic effect?
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Osmotic diuresis - is the diuretic effect caused by a high osmotic gradient between kidney filtrate and the surrounding medulla/capillaries.Osmosis is the movement of water from an area of high concentration to an area of lower concentration.
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Examples of an osmotic diuretic effect?
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hyperglycemia and excess salt intake both cause dehydration
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Sympathetic nerves ______ the heart rate.
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Sympathetic nerves INCREASE the heart rate.
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Parasympathetic nerves _______ the heart rate.
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Parasympathetic nerves DECREASE heart rate.
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What role do the arterioles play in blood pressure?
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Arterioles:
1. determine the peripheral resistance 2. regulate relative blood flow through particular organs. |
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What things might cause vasodilatation?
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Vasodilatation is caused by:
- adrenaline acting on B2-adrenoceptors - Nitric Oxide - inflammatory mediators |
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What might cause vasoconstriction?
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Vasoconstriction is caused by:
- increase in cellular calcium ions - noradrenaline acting on Alpha1 adrenoceptors |
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Name three causes of hypertension.
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Hypertension can be caused by:
1. unknown cause 2. endocrine disorders 3. renal disease 4. tumour |
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If hypertension is untreated, what conditions may ensue?
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Untreated hypertension can lead to:
1. coronary thrombosis 2. stroke 3. kidney failure |
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What is the effect of taking thiazides alongside other drugs for hypertension?
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Thiazides increase the effect of other antihypertensive drugs.
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What organ releases renin?
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kidney
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What is the action of ACE?
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ACE cleaves Angiotensin I into Angiotensin II.
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Name some actions of Angiotensin II.
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Angiotensin II causes:
1. Salt retention (via aldosterone secretion) 2. Vasoconstriction 3. Vascular growth |
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What does Angiotensin I do increase blood pressure?
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Angiotensin I is a weak vasoconstrictor, which increases blood pressure by inhibiting bradykinin (a vasodilator). This increases peripheral resistance.
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Where is the ACE located?
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The ACE is located on the vascular endothelium of the lungs.
Since all blood must return to the right heart and be sent through the lungs, ACE located in the lungs will affect all the Angiotensin I. |
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What effect does Angiotensin II have on other organs?
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Angiotensin II is a powerful vasoconstrictor which reduces blood flow to all other rgans.
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Name an ACE inhibitor and state its action?
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ACE inhibitors:
e.g. Ramipril, Lisinopril, Captopril Actions= 1. inhibit conversion of Angiotensin I --> Angiotensin II 2. increased bradykinin levels 3. reduces angiotensin II levels 4. reduces aldosterone levels 5. vasodilation & reduced peripheral resistance |
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Name an Angiotensin II Receptor Antagonist and state its action?
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Losartan / Valsartan
Actions: 1. inhibits receptors in tissues 2. indirectly reduces aldosterone levels 3. vasodilatation & reduced peripheral resistance |
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Compare and contrast ACE inhibition and Angiotensin II receptor inhibition?
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ACE inhibition:
- acts before Angiotensin II is produced - means bradykinin is not inhibited Angiotensin II receptor inhibition - |
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What is the mechanism of action of aldosterone? Which organ secretes it and on what organ does it act?
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Aldosterone is secreted by the adrenal gland.
It switches on Na+/K+ ATPase in the kidneys. Blood reabsorbs Na+ and secretes K+. Water follows Na+ into blood, blood volume and BP increase. |
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What effect does ACE have on bradykinin?
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In the normal Renin-Angiotensin pathway, ACE inhibits bradykinin.
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What is the action of bradykinin?
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Bradykinin is a hormone vasodilator that decreases peripheral resistance.
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What effect does ACE inhibition have on bradykinin levels?
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ACE inhibition means that bradykinin remains active, and able to cause vasodilation. Peripheral resistance is decreased.
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Name some contraindications for the SARtAn drugs
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Angiotensin II receptor antagonists should not be used:
1. in pregnancy or breastfeeding 2. caution in renal artery stenosis |
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What does SARTAN stand for?
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Second generation
Angiotensin II RecepTor ANtagonistS |
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Adverse effects of the SARTANS?
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Sartan adverse effects?
1) severe hypotension 2) diarrhoea 3) muscle cramps 4) dizziniess 5) cough 6) insomnia |
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Adverse effects of ACE inhibitors?
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ACE inhibitors adverse effects?
1) hypotension 2) dry cough (from bradykinin) 3) dizziness 4) headache 5) diarrhoea 6) muscle cramps |
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Name some calcium channel blocker drugs used in hypertension.
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Calcium Channel Blockers:
e.g. Verapamil, Nifedipine |
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What is the action of calcium channel blockers and how do they work?
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calcium channel blockers
relax vascular smooth muscle block calcium ion channels inhibit depolarisation-induced calcium entry into cardiac and vascular smooth muscle vasodilator effect arterial pressure is reduced |
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What are the side effects of calcium channel blockers?
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Calcium channel blockers:
1) ankle oedema 2) flushing |
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Name some contraindications for the SARtAn drugs
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Angiotensin II receptor antagonists should not be used:
1. in pregnancy or breastfeeding 2. caution in renal artery stenosis |
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What does SARTAN stand for?
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Second generation
Angiotensin II RecepTor ANtagonistS |
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Adverse effects of the SARTANS?
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Sartan adverse effects?
1) severe hypotension 2) diarrhoea 3) muscle cramps 4) dizziniess 5) cough 6) insomnia |
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Adverse effects of ACE inhibitors?
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ACE inhibitors adverse effects?
1) hypotension 2) dry cough (from bradykinin) 3) dizziness 4) headache 5) diarrhoea 6) muscle cramps |
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Name some calcium channel blocker drugs used for hypertension
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Calcium channel blockers:
Nifedipine, Amlodipine, Verapamil |
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What adverse effects do calcium channel blockers hve?
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Calcium channel blockers can cause:
1) ankle oedema 2) flushing 3) reflex tachycardia |
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What is the action of calcium channel blockers and how do they work?
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calcium channel blockers:
relax cardiac and vascular smooth muscle, reducing arterial pressure |
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Name two classes of calcium channel blocker and give an example of each.
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Phenylakylamines (Verapamil)
Dihydropyridines (Nifedipine, Amlodipine) |
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Explain how Phenylakylamines and Dihydropyridines differ (compare and contrast)
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Phenylakylamines (Nifedipine, Amlodipine) act on both arteriolar and cardiac smooth muscle.
Dihydropyridines (Verapamil) act only on cardiac smooth muscle. |
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Do calcium channel blockers have a negative or positive inotropic effect?
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Calcium channel blockers have a negative inotropic effect. Inhibition of calcium entry into smooth muscle reduces its contractility.
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Can calcium channel blockers be given to patients with cardiac failure?
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No.
Calcium channel blockers have a negative inotropic effect. |
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What are Beta-blockers?
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Beta blockers are Beta adrenoceptor antagonist agents.
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What is the action of a Beta-blocker?
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Beta adrenoceptor antagonists:
- block B1 and/or B2 receptors in cardiac, vascular and pulmonary smooth muscle. |
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How do Beta-blockers work?
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Beta adrenoceptor antagonists work by:
1. reducing cardiac rate and force 2. negative inotropic effect 3. reduce cardiac output 4. reduce BP 5. reduce sympathetic activity |
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Name the two types of Beta blocker agent and give an example of each.
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Beta blockers may be selective or non-selective.
Atenolol is selective for B1 receptors. Propanalol is non-selective and acts on both B1 & B2 receptors. |
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What is the advantage of a B1 selective Beta blocker drug?
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A selective B1 selective beta-blocker drug will only act on the heart (having a negative inotropic effect). It will not relax vascular smooth muscle.
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Name a drug that has affinity for B1 adrenoceptors, and state its action.
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- Atenolol
- Beta1 adrenoceptor antagonist - is cardiac selective - has netagive inotropic effect i.e. reduces cardiac contractility, oxygen demand and BP |
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Name a drug that can act on both Beta 1 and 2 adrenoceptors, and say where these receptors are found.
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Propanalol is a Beta adrenoceptor antagonist.
It non-selectively blocks both type 1 & 2 receptors. B1 - in heart B2 - in vascular smooth muscle and lungs |
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What conditions might be treated using beta-blockers?
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Beta blockers used to treat:
- angina - post MI - hypertension - anxiety |
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When should you not give a Beta-blocker?
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Beta-blockers not to be used:
- in asthma - hypotension - congestive cardiac failure - bradycardia (conditions where the heart is slowed) |
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Adverse effects of Beta-blockers?
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Beta blockers adverse effects:
- heart failure - airways obstruction - cold extremities (B2 effect) - PVD / Raynaud's - hallucinations/nightmares |
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What is the action of Alpha 1 adrenoceptor antagonists?
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Alpha 1 receptor blockers:
- block the Alpha 1 receptors - causing vasodilation and reduced peripheral resistance |
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What is the Alpha 1 adrenoceptor agonists mode of action?
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cause vasoconstriction Positive inotropic effect
increase BP |
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What other useful cardiovascular side effect do Alpha 1 adrenoceptor antagonists agents have?
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Alpha 1 adrenoceptor antagonists also lower plasma LDL and increase HDL
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Alpha 1 adrenoceptor antagnonist adverse effects?
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Alpha 1 adrenoceptor antagonist adverse effects:
- hypotension - headache - dry mouth - impotence |
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Why is a thiazide diuretic helpful in treating hypertension?
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increases salt and water excretion, thus reducing blood volume and peripheral resistance, cardiac output
increases renin release |
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Explain the action of the first generation antihypertensive drugs.
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First generation antihypertensive drugs.
= ACE inhibitors = Ramipil, Lisinopril = inhibit conversion of angiotensin I to II = increase bradykinin (vasodilator) = reduce peripheral resistance = decrease angiotensin II (vasoconstrictor) = decrease aldosterone = reduce BP |
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Explain the action of the second generation antihypertensive drugs.
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2nd generation antihypertensives.
e.g. Angiotension II recepor blockers (Losartan, Valsartan) = cause vasodilatation and reduce peripheral resistance |
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Name two antihypertensive drugs where cough is a side effect.
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Cough is a side effect of
ACE inhibitors (Ramipril, Lisinopril) and Angiotensin II receptor antagonists (Losartan, Valsartan) |
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State one absolute contraindication for ACE inhibitors.
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ACE inhibitor contraindication = pregnancy
= Renovascular disease |
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State one absolute contraindication for Angiotensin II receptor antagonists.
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Angiotensin II receptor blocker contraindication
= pregnancy = Renal artery stenosis |
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Name an Alpha 1 adrenoceptor antagonist agent, and state its MOA.
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Alpha 1 adrenoceptor antagonist
= Doxazosin = reversibly blocks Alpha 1 adrenoceptors = causes vasodilatation = reduces peripheral resistance = also lowers LDL and raises HDL |
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Outline the NICE (2006) guildelines for the management of hypertension.
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-(long answer)
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Name the drugs that act on the ACE system, including first and second generation drugs.
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1st generation=
ACE inhibitors (Ramipril, Lisinopril) 2nd generation= Angiotensin II Receptor antagonists (Losartan, Valsartan) |
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Describe the action of one positive inotropic agent and one negative inoptropic agent in the management of cardiovascular conditions.
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positive inotropic agent=digoxin
negative inotropic=calcium channel blocker nifedipine |
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What is the relevance of genetic variation when considering intervention with ACE inhibitors?
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ACE inhibitors normally reduce BP and slow progression of renal disease.
But individual respond differently to them. ACE activity depends partially on genotype. If pt. doesn't respond try calcium channel blockers, diuretics |
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List the main modes of action by which antihypertensive drugs reduce blood pressure.
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Various agents availablem main MOAs are:
1. reducing blood volume (diuretics) 2. reducing cardiac contractility (calcium channel blockers, Beta blockers) 3. reducing peripheral resistance (CCBs, ACE inhibition, SARTANs, Alpha adrenoceptor blockers |
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What are the potential problems of using diuretic therapy?
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Problems of diuretic therapy inc:
a) impaired glucose tolerance b) uric acid retention c) excessive sodium loss d) excessive potassium loss e) rare allergy |
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Is propanalol safe to use in patients with congestive heart failure?
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-
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True/false?
Atenolol does not precipitate asthma. |
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True/false?
Down-regulation of adrenoceptors may occur in long-term propanalol use. |
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True/false?
Plasma concentrations are closely related to clinical activity. |
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True/false?
Calcium channel blockers are negatively inotropic |
True
Calcium channel blockers are negatively inotropic |
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True/false?
Calcium channel blockers are all highly selective for vascular smooth muscle |
False
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True/false?
Nifedipine may sometimes cause angina |
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True/false?
Nifedipine can be used in hypertensive crisis |
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True/false?
Verapamil is an effective antiarrhthmic for ventricular arrhthmias |
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Name three possible causes of systemic oedema.
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Causes of systemic oedema:
- congestive heart failure - liver failure - renal impairment |
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Loop diuretics - contraindications?
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Loop diuretics contraindications:
- severe renal impairment - use of Digoxin (risk of potassium deficiency) |
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Loop diuretics adverse effects?
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Loop diuretics adverse effects:
- K & Na deficiency - hypotension - high uric acid levels - hypovolemia |
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MOA of calcium channel blockers
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1) block calcium ion channels
2) inhibit depolarisation-induced calcium entry into cardiac and/or vascular smooth muscle cells 3) vasodilatation occurs 4) arterial pressure is reduced |
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action of renin?
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cleaves Angiotensinogen into Angiotensin I
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what organ does angiotensinogen come from?
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the liver
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what organs excrete Aldosterone?
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Adrenal Glands
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what organ does Aldosterone act on?
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kidney
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what is the action of Aldosterone?
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blood reabsorbs more sodium and water in kidney
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bradykinin has what effect?
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vasodilation
(brady = slow) |
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does ACE inhibit or stimulate bradykinin?
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inhibit
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ACE inhibitors have what effect on bradykinin production?
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they increase bradykinin production
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increasing bradykinin production causes...?
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vasodilation
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what substance stimulates aldosterone release from the adrenal glands?
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angiotensin II
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