Treatment of Hypertension and Heart Failure Flashcards
What are the 2 elements of control of blood pressure?
The autonomic nervous system, and the RAAS system
What is RAAS?
Renin-angiotensin-aldosterone system which allows the kidney to control blood pressure
Describe the mechanism of action of the RAAS system.
Decreased renal perfusion due to low blood pressure causes increased release of renin.
Renin converts angiotensinogen to angiotensin 1.
ACE converts angiotensin 1 to angiotensin 2.
Angiotensin 2 causes 3 things to happen:
1. Increased aldosterone output
2. Direct salt and water retention in kidney
3. Causes vasoconstriction
What are the 3 BHS classifications of hypertension?
Grade 1 (mild) 140-159/90-99 Grade 2 (moderate) 160-179/100-109 Grade 3 (severe) >180/>110
What are the first line treatments for hypertension in pts under 55?
ACE inhibitor or ARB if not tolerated
What are the second line treatments for hypertension in pts under 55?
Combining a calcium channel blocker with the ACEI/ARB
What are the third line treatment for hypertension in pts under 55?
ACEI/ARB + Calcium channel blocker + thiazide diuretic
What are the fourth line treatments for hypertension in pts under 55?
ACEI/ARB + Calcium Channel blocker + Thiazide diuretic + Low does spironolactone
What are the first line treatments for hypertension in pts over 55 or of African or Caribbean origin?
Calcium Channel blocker
Or
Thiazide diuretic if CCB not tolerated
What are the second line treatments for hypertension in pts over 55 or of Africa or Caribbean origin?
CCB or Thiazide diuretic, + ACEI/ARB
What are the third line treatment for hypertension in pts over 55 or of African or Caribbean origin?
ACEI/ARB + Calcium Channel blocker + Thiazide diuretic
What are the fourth line treatment for hypertension in pts over 55 or of African or Caribbean origin?
ACEI/ARB + Calcium Channel blocker + Thiazide diuretic + Low does spironolactone
How do ACE inhibitors work?
By competitively inhibiting ACE to reduce angiotensin 2 formation
What are the most commonly used ACE inhibitors?
Ramipril
Lisinopril
Enalapril
What are the main side effects associated with ACE inhibitors?
Dry cough (10-15%)
Hyperkalaemi
Renal failure
How do ARBs work?
Bind to angiotensin 1 to prevent conversion to AT2 to prevent aldosterone production and vasoconstriction of renal artery.
Are ARBs well tolerated?
Generally, yes. They have few side effects.
What are the few side effects of ARBs?
Renal failure
Hyperkalaemia
What are the commonly used ARBs?
Losartan
Valsartan
Candesartan
How many classes of calcium channel blockers are there?
3
How do calcium channel blockers work?
Bind to specific alpha subunits of L-type calcium channels to reduce cellular calcium entry.
What are the three classes of calcium channel blockers?
- Dihydropyridines
- Phenylalkylamines
- Benzothiazepines
Which calcium channel blockers come under the category of dihydropyridines?
Nifedipine
Amlodipine
Which calcium channel blockers come under the category of benzthiazepines?
Diltiazem
Which calcium channel blockers come under the category of phenylalkyamines?
Verapamil
What effect do calcium channel blockers have on the body?
- Peripheral vasodilation
- Coronary artery vasodilation
- Pulmonary artery vasodilation
Which calcium channel blockers are good for rate control?
Verapamil
Diltiazem
Which calcium channel blockers are good for ischaemic heart disease and heart failure?
Amlodipine
Nifedipine
Are amlodipine and nifedipine used in the acute setting?
No as they a large volume of distribution so therapeutic levels take a while to establish
Which kind of calcium channel blockers are good for use in heart failure?
Dihydropyridines i.e. amlodipine and nifedipine, as the others can worsen heart failure.
How do thiazide diuretics work?
Reduce distal tubular resorption of Na+
What are the ADRs associated with thiazide diuretics?
Hypokalaemia
Hyperuraemia
Impaired glucose tolerance
A diabetic patient i started on bendroflumethiazide and atenolol. What is the worry here?
The combination of those 2 drugs can impair glucose tolerance
Which condition is a contraindication for thiazide diuretics?
Gout
If a pt has angina as well as high blood pressure, what additional drug may be beneficial for both conditions?
Beta blocker
Name some beta bockers.
Atenolol
Bisoprolol
Nebivolol
Which condition are beta blockers contraindicated in?
Asthma
Other than the commonly used drugs and beta blockers, which other drug classes can lower BP?
Alpha blockers
Direct renin inhibitors
Centrally acting agents
Give and example of an alpha blocker?
Doxazosin
In which position do alpha blockers have the most effect on blood pressure?
The upright position i.e. they can cause postural hypotension
Which centrally acting agents can lower BP?
- Methylopa
- Clonidine
- Moxoxidil
What is the aetiology of heart failure?
IHD HTN Cardiomyopathies Valvular disease Conduction pathway pathology
This leads to LV dysfunction