S3: hypertension, heart failure & diuretics Flashcards

1
Q

What are the target BP measurements for different age groups?

A

<140/90 in patients younger than 80 including type II diabetes
<150/90 in patients older than 80
<135/85 in patients with type I diabetes (without metabolic syndrome)

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2
Q

What are the different stages in hypertension?

A

Stage 1: clinic BP ranging from 140/90-159/99; ABPM/HPBM > 135/85 mmHg
Stage 2: clinic BP ranging from 160/100-180/120; ABPM/HPBM > 150/95 mmHg
Stage 3: clinic systolic BP of 180mmHg or higher OR clinic diastolic BP of 120mmHg or higher

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3
Q

Describe the action of ACE

A

Found on luminal surface of capillary endothelial cells, predominantly in the lungs
ACE catalyses conversion of angiotensin-I to potent, active vasoconstrictor – angiotensin II

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4
Q

Describe the action of angiotensin-II

A

Affords action through AT1 (and AT2 receptors)
AT1 receptor subtype typical of classical angiotensin-II actions
-stimulation of aldosterone which acts at distal renal tubule
-cardiac and vascular muscle cell growth
-ADH release from posterior pituitary

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5
Q

Describe the action of ACEi

A

Limits the conversion of angiotensin-I to angiotensin-II by inhibiting circulating and tissue ACE
A reduction in angiotensin-II activity, resulting in:
-vasodilation (decrease peripheral resistance, decrease afterload)
-reduction in aldosterone release
-reduced ADH release
-reduced cell growth and proliferation
(NOTE: angiotensin-II also produced from angiotensin-I independently of ACE via chymases)

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6
Q

Describe the relationship between ACEi and bradykinin

A

Bradykinin is a substrate for ACE
Use of ACEi therefore increases the amount of bradykinin
-bradykinin causes vasodilation via NOS/NO and PGI2

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7
Q

List examples of ACEi

A

Lisinopril

Ramipril

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8
Q

What are the adverse effects, warnings, contraindications & important drug interactions of ACEi?

A

Adverse effects: hypotension, dry cough, hyperkalaemia, cause or worsen renal failure & angioedema
Warnings, contraindications: renal artery stenosis, AKD, pregnancy, CKD, idiopathic angioedema
Important drug interactions: increasing K+ drugs, NSAIDs & other antihypertensive agents

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9
Q

List examples of angiotensin II receptor antagonists

A

Candesartan

Losartan

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10
Q

Describe the action of angiotensin II receptor antagonists (ARB)

A

AT1 receptors

No effect on bradykinin – less effective in low-renin hypertensive patients

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11
Q

What are the adverse effects, warnings, contraindications & important drug interactions of angiotensin II receptor antagonists?

A

Adverse effects: hypotension, hyperkalaemia & cause or worsen renal failure
Warnings, contraindications: renal artery stenosis, AKD, pregnancy, (CKD-caution)
Important drug interactions: increasing potassium drugs & NSAIDs

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12
Q

Describe the action of L-type calcium channels and calcium channel blockers

A

LTCCs allow inward Ca2+ flux into cells – voltage operated calcium channel (VOCC)
Expressed throughout the body, including vascular smooth muscle cells and cardiac myocytes plus SA and AV nodes
CCBs target calcium initiated smooth muscle contraction
3 classes of CCB interact with different sites on (a1) subunit of VOCC – they have different selectivity for VSM/myocardium

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13
Q

What are the different classes of calcium channel blockers?

A

Dihydropyridines – selective for peripheral vasculature, little chronotropic (rate) or inotropic (force) effects
Phenylalkylamines – depresses SA node and slows AV conduction, negative inotropy
Benzothiazapines sit in the middle
CCBs – primary choice antihypertensive in low renin patients

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14
Q

List examples of the dihydropyridine class

A

Amlodipine – has a long half life, others tend to be shorter
Nimodipine – selectivity for cerebral vasculature (useful in subarachnoid haemorrhage)
Nifedipine

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15
Q

What are the adverse effects, warnings, contraindications & important drug interactions of dihydropyridine class?

A

Adverse effects: ankle swelling, flushing, headaches, palpitations
Warnings, contraindications: unstable angina, severe aortic stenosis
Important drug interactions: amlodipine & simvastatin causes increased effect of the statin

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16
Q

Describe the action of phenylalkylamines

A

Class IV anti-arrhythmic agent, prolongs the action potential (effective refractory period)
Less peripheral vasodilation, negative chronotropic and inotropic effects
Used for arrhythmias, angina, (hypertension)

17
Q

What are the adverse effects, warnings, contraindications & important drug interactions of phenylalkylamines?

A

Adverse effects: constipation, bradycardia, heart block and cardiac failure
Warnings, contraindications: poor LV function, AV nodal conduction delay
Important drug interactions: B-blockers, caution with other antihypertensive and antiarrhythmic agents

18
Q

List examples of phenylalkylamines

19
Q

List examples of benzothiazapines

20
Q

Describe the action of thiazide and thiazide-like diuretics

A

Inhibit Na+/Cl- transporter in DCT
-decreased Na+ and H20 reabsorption
(Long term effects mediated by sensitivity of VSM to vasoconstrictors Ca2+/NAd)
Useful over CCB in oedema

21
Q

What are the adverse effects, warnings, contraindications & important drug interactions of thiazide and thiazide-like diuretics?

A

Adverse effects: hypokalaemia, hyponatraemia, hyperuricemia (gout), arrhythmia, increased glucose (especially with beta-blockers), small increase in cholesterol & triglyceride
Warnings, contraindications: hypokalaemia, hyponatraemia, gout
Important drug interactions: NSAIDs, decreasing K+ drugs such as loop diuretics

22
Q

List examples of thiazide and thiazide-like diuretics

A

Bendroflumethiazide

Indapamide

23
Q

What is the two-pronged approach in treated hypertension with primary diabetes?

A

ACEi/ARB decreases diabetic nephropathy and CKD with proteinuria by dilation of efferent glomerular arteriole
Decreased peripheral vascular resistance -> decreased BP and dilation of efferent glomerular arteriole -> reduced intraglomerular pressure (good for type II diabetes)

24
Q

What drugs can be given for resistant hypertension (if BP is not controlled after step 3)?

A

Spironolactone – aldosterone receptor antagonist (stops the transcription of ENaC channel)
Alpha and beta blockers would be considered instead of spironolactone if high K+
Centrally acting drugs – labetalol (pregnancy, hypertensive emergency) -> reduces sympathetic outflow

25
What are the adverse effects, warnings, contraindications & important drug interactions of spironolactone?
Adverse effects: hyperkalaemia, gynaecomastia (due to anti androgen actions) Warnings, contraindications: hyperkalaemia, Addison’s Important drug interactions: increasing K+ drugs, pregnancy
26
Describe the action of beta-adrenoreceptor blockers
Decrease sympathetic tone by blocking NAd and reducing myocardial contraction resulting in reduced cardiac output Reduced renin secretion (B1)
27
What are the adverse effects, warnings, contraindications & important drug interactions of beta-adrenoreceptor blockers?
Adverse effects: bronchospasm, heart block, Raynaud’s (cold hands), lethargy, impotence, mask tachycardia (sign of insulin induced hypoglycaemia) Warnings, contraindications: asthma, haemodynamic instability, hepatic failure Important drug interactions: verapamil and diltiazem (asystole)
28
List examples of beta-adrenoreceptor blockers
Labetalol Bisoprolol Metoprolol
29
Describe the action of alpha-adrenoreceptor blockers
Selective antagonism of alpha-1 adrenoreceptors Reduce peripheral vascular resistance Urinary tract including bladder neck and prostate (BPH – tamsulosin) Relatively safe in renal disease
30
What are the adverse effects, warnings, contraindications & important drug interactions of alpha-adrenoreceptor blockers?
Adverse effects: postural hypotension (dizziness, syncope, headache and fatigue) Warnings, contraindications: postural hypotension Important drug interactions: patients affected by dihydropyridine CCB (increased oedema)
31
List examples of alpha-adrenoreceptor blockers
Doxazosin | tamsulosin for BPH
32
Describe management of heart failure
Correct underlying cause if you can Non pharmacological management – decrease salt intake and liquid reduction if high Avoid K+ salt substitutes Diuretics and other therapeutic agents AIMS: reduction in symptoms, managed increase in exercise tolerance, increase quality of life and slow morbidity
33
Describe the action of loop diuretics
Inhibit Na+/K+/2Cl- co-transporter in ascending limb of LoH Direct dilation of capacitance veins – reduces preload Used for acute pulmonary oedema, fluid overload in HF, adjunct in nephrotic syndrome
34
What are the adverse effects, warnings, contraindications & important drug interactions of loop diuretics?
Adverse effects: dehydration, hypotension, hypokalaemia, hyponatraemia, hyperuricaemia, arrhythmia, tinnitus, increased cholesterol and triglyceride Warnings, contraindications: hypokalaemia, gout, hepatic encephalopathy Important drug interactions: aminoglycosides, digoxin, lithium
35
List examples of loop diuretics
Bumetanide | Furosemide
36
Describe the action of potassium sparing diuretics
Block ENaC – decreases Na+ reabsorption in DCT and reduces K+ excretion Often used as adjunct to loop or thiazide like in HF to limit decrease in K+
37
What are the adverse effects, warnings, contraindications & important drug interactions of potassium sparing diuretics?
Adverse effects: hyperkalaemia, potential arrhythmia Warnings, contraindications: Addison’s, potassium supplements Important drug interactions: other K+ sparing drugs, ACEi & ARBs
38
List examples of potassium sparing diuretics
Amiloride
39
Why is spironolactone given in HF?
In some individuals, refractory hyperaldosteronism occurs in spite of ACEi/ARB Spironolactone given as an adjunct to ACEi/ARB and diuretic All-cause mortality decreases significantly