Hypertension: Pharmacology Flashcards

1
Q

How do diuretics reduce BP?

A

By reducing intravascular volume

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2
Q

What thiazide and thiazide-like diuretics are used to treat HTN?

How do they work?

A

Thiazide:

  • Bendroflumethiazide
  • Hydrochlorothiazide

Thiazide-like:

  • Chlortalidone
  • Indapamide

Act at the DCT, inhibiting Na+/Cl- co transporter from the lumen, increasing water, Na+ and therefore K+ loss also.

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3
Q

What are the side effects of thiazide and thiazide-like diuretics?

A
  • High uric acid = gout
  • Hypokalaemia
  • Hyponatraemia
  • High glucose
  • High cholesterol
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4
Q

What are thiazide and thiazide-like diuretics used to prevent?

A

Used to prevent MI and stroke

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5
Q

What potassium-sparing diuretics are used to treat HTN?

What are the side effects?

A

Aldosterone antagonists:

  • Spironolactone
  • Eplerenone

Epithelial Na+ channel blockers:

  • Amiloride

Side effects:

  • Hyperkalaemia
  • Hyponatraemia
  • Gyanaecomastia (spironolactone)
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6
Q

How are B1 and B2 adrenoceptor blockers used in HTN?

Which drugs are used? Which receptors do they work on?

A
  • Negative inotropic and chronotropic effects
  • Reduced AV node conduction
  • Prevention of MI and stroke

Drugs:

  • Atenolol (B1 cardioselective)
  • Bisoprolol (B1 and B2)
  • Propranolol (B1 and B2)
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7
Q

What are the side effects of Beta blockers?

A
  • Broncospasm
  • Lethargy
  • Heart failure
  • Reynaud’s
  • Reduced HDL cholesterol
  • Diarrhoea
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8
Q

What do calcium channel blockers act on?

What effect is caused?

A
  • Vascular smooth muscle- relaxation
  • Cardiomyocytes - reduced contractility & HR
  • AV and SA nodes - reduced contracility & HR
  • Renal tubules - natriuresis and diuresis
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9
Q

Which calcium channel blockers are used in HTN?

A
  • Verapamil
  • Diltiazem
  • Dihydropyridines: nifedipine, amlodipine
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10
Q

How does verapamil work for HTN?

What are its effects on the CVS?

A

Mostly works on cardiac muscle. Slow Ca entry during phases 2 and 3 of cardiac action potential. Useful for tachyarrythmia esp. re-entry and atrial origin. Slow AV node conduction and therefore useful for atrial flutter. Little effect on vasomotor tone.

  • Reduces SVR from peripheral vasodilation
  • Coronary vasodilation
  • Decreased cardiac contractility
  • Reduces heart rate
  • Mild reduction in stroke volume

(Mild decrease in BP)

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11
Q

What are the side effects of verapamil?

A
  • Heart failure
  • Heart block
  • Peripheral oedema
  • Facial flush
  • Headaches
  • Constipation
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12
Q

How does diltiazem work for HTN?

A

Affects cardiac smooth muscle

  • Mild reduction in SVR through peripheral vasodilation
  • Moderate coronary vasodilation (useful for angina)
  • Moderate slowing of AV node- antiarrhythmic
  • Mild reduction in HR and SV

Mild decrease in BP

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13
Q

What are the side effects of diltiazem?

A
  • Facial flush
  • Heart failure
  • Heart block
  • Peripheral oedema
  • Headaches
  • Constipation

(Same as verapamil)

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14
Q

What is diltiazem used for?

A

HTN

Angina

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15
Q

How do dihydropyridines work in HTN?

A
  • Peripheral vasodilation (reduced SVR)
  • Cardiac vasodilation
  • Mild decreased cardiac contractility
  • Reflex increase in sympathetic tone
  • Mild slowing of AV node conduction
  • Increase in HR (compensatory from drop in BP)
  • Natriuresis and diuresis
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16
Q

Which dihydropyridines are used in HTN?

A
  • Nifedipine
  • Amlodipine
  • Lercanidipine
17
Q

How do dihydropyridines increase HR?

A

Lowering BP causes compensatory increase in HR

18
Q

Name some circumstances in which the RAAS system is activated

A
  • Hypotension
  • HF
  • Septicaemia
19
Q

How do ACE inhibitors work in HTN?

A

Inhibit all formation in the RAAS system preventing increased BP.

Inhibit bradykinin breakdown

20
Q

What are the side effects of ACE inhibitors?

A
  • Cough
  • Angio oedema
  • Hyperkalaemia
  • Caution in renal artery stenosis
21
Q

Why do ACE inhibitors cause a dry cough?

A

Prevent the breakdown of bradykinin resulting in more active bradykinin in the lungs = cough

22
Q

Which Angiotensin II receptor blockers are used for HTN?

How do they work to treat HTN?

A
  • Losartan
  • Valsartan
  • Candesartan

Blocking angiotensin II receptors preventing their effects on blood pressure and the production of aldosterone.

23
Q

What are the side effects of angiotensin receptor blockers?

A
  • Generally well tolerated
  • Caution in renal artery stenosis
  • Hyperkalaemia
  • Myalgia
  • Raised CPK
24
Q

Which alpha receptor blockers are used in HTN?

How do they work to reduce BP?

What are their side effects?

A
  • Doxazosin
  • Phenoxybenzamine for phaeochromocytoma- in emergencies

Used in combination with other therapies

Side effects:

  • Hypotension with first dose
  • Postural hypotension
25
Q

What are alpha1 receptor blockers also used for?

A

BPH

26
Q

What are the BP targets for under 80s?

A

<140/90 in clinic

<135/85 AMBP/HMBP

27
Q

What are the BP targets for those 80 years and over?

A

<150/90 in clinic

<145/85 AMBP/HMBP

28
Q

What is the first line pharmacological treatment for a person with HTN and T2DM or who is <55 and not from black Afro-Caribbean origin?

What is the second line?

A

1st line: ACE inhibitor or ARB

2nd line: ACE-inhibitor or ARB + CCB or thiazide-like diuretic

29
Q

What is the first line pharmacological treatment for a person with HTN without diabetes or who is >55 or of black Afro-Caribbean origin?

What is the second line?

A

1st line: CCB

2nd line: CCB + ARB or ACE-i

30
Q

What is the third line pharmacological treatment for HTN regardless of diabetes, ethnicity or age?

A

CCB + ACE-i or ARB + thiazide-like diuretic

31
Q

What is the 4th line treatment for HTN regardless of diabetes, ethnicity or age?

A

Confirm resistant HTN with ABPM or HBPM and discuss adherence.

Seek expert advice or add:

  • Low dose spironolactone if serum K+ 4.5mmol/L or less
  • Alpha blocker or beta blocker if serum K+ >4.5mmol/L

Seek expert advice if BP remains uncontrolled on optimal tolerated doses of 4 drugs