Hypertension

Question 1

What is the clinical range you aim for when controlling a patients BP?

Answer 1

140/90

Diastolic 80 in diabetics

Question 2

Describe the RAA system for maintaining BP?

Answer 2

Low renal perfusion stimulates the release of renin from the kidneys.

Renin converts angiotensinogen into angiotensin I.

ACE converts angiotensin I into angiotensin II.

Angiotensin II causes vasoconstriction of arterioles and stimulates release of aldosterone from the adrenal gland.

Aldosterone causes reabsorption of Na+ and secretion of K+ from the distal convoluted tubule and collecting ducts.

(water follows Na+ therefore increasing circulating volume)

Question 3

Describe the actions of ACEI and give examples of these drugs, side effects and important adverse drug reactions?

Answer 3

ACE Inhibitors: Inhibit ACE enzyme therefore stop the actions of angiotensin II and aldosterone. Also stops bradykinin from being converted to inactive metabolites. (Bradykinin is a vasodilator but is also responsible for the side effect of dry coughs, also causes severe 1st dose hypotension)

They reduce arteriole vasoconstriction and reduce circulating volume by reducing the reabsorption of Na+.

Egs: 
Ramipril
Lisinopril
Enalopril 
Catopril 

Aka if it ends in …..ril its a ACE Inhibitor.

S/e: Dry cough, 1st dose hypotension
Adverse effects: Raises K+. Angioedema (rare)

Question 4

When is using an ACE Inhibitor not recommended?

Answer 4

In renovascular disease as it can cause a drop in renal function due to under perfusion.

If a patient has a sudden drop in renal function.

Paradoxically it is 1st line in diabetic nephropathy.

Question 5

Describe the action of angiotensin I receptor antagonists and give examples?

Answer 5

Blocks binding of angiotensin to the angiotensin I receptors therefore causes the same effects as ACE I, except for the dry cough as it does not affect bradykinin.

It is therefore a good alternative for those who have poor compliance due to the dry cough.

E.g.
Candesartan
Losartan
Valsartan

Suffix = artan

Question 6

Describe the different type of vasodilator drugs which can be used?

Answer 6

ACE Inhibitors
Angiotensin II receptor antagonists
Ca channel blocker
Alpha 1 receptor antagonists (alpha blockers)

Question 7

Describe the mechanism of action of Ca channel blockers and give examples?

Answer 7

They act on the voltage gated channels on vascular smooth muscle leading to vasodilation and a drop in BP.

In rate limiting Ca channel blockers affects the voltage gated channels of the heart, slows the heart rate NEVER GIVE WITH B BLOCKERS!

Verapamil (Rate limiting)

Dihydropyridines (Smooth muscle)
Felodopine
Amlodopine
Nifedipine

Suffix = pine

Question 8

Describe the effects of Alpha blockers and give examples?

Answer 8

Competitively inhibit the alpha 1 receptors.

Therefore causes vasodilatation of vessels but also causes other anti adrenergic s/e therefore it is the last choice antihypertensive.

Doxzaocin, Prazocin

Question 9

Describe the use of thiazide and thiazide like diuretics in the treatment of hypertension, examples and contraindications?

Answer 9

Third line: Thiazide like diuretics

Reduces reabsorption of Na+ and Cl- from the distal convoluted tubule.

Important considerations:
Doesn’t work in moderate renal failure

Side effects:
Hypotension
Hypokalaemia
Impaired glucose tolerance
Makes gout worse

Eg:

Thiazides: Bendroflumethazide
Thiazide like: chloratidone and linapamide

Question 10

Describe the mechanism of action of Beta Blockers?

Answer 10

Block Beta receptors on the heart and reduce cardiac output therefore reducing BP.

Also reduces the amount of sympathetically stimulated renin.

Contrainidcated in Asthma, and should never be given with a rate limiting Ca chanel blocker.

E.g:
Atenolol
Propanolol

Question 11

Who should receive pharmaceutical treatment for hypertension?

Answer 11

Hypertension
Stage 1: >140/>90
Stage 2: >160/>100
Severe: >180/>110

Stage 1 with one or more of
End organ damage
Diabetes
CV disease 
High CV risk (>20% over 10 years – see rear of BNF)

All patients with Stage 2

Note measurements vary for ambulatory monitoring and GP surgery monitoring, (if you suspect white coat syndrome send them home with ambulatory monitoring)

Question 12

What lifestyle changes should you recommend for a hypertensive patient?

Answer 12

Smoking cessation
Weight reduction
Increase exercise
Reduce excess caffeine intake
Reduce alcohol intake
Diet (reduce fats and salt eat more fruit + veg)

Question 13

Outline the drug regimen you should use for treating hypertension?

Answer 13

Are you black or older than 55? (Older and black people have lower levels of renin)

No:

1. ACE inhibitor
2. Ca channel blocker
3. Diuretic
4. Add alpha blocker
   or spironolactone (aldosterone receptor antagonist)
   or other diuretic
   Or beta blocker

Yes:

1. Ca channel blocker
2. ACE inihibitor
3. Diuretic
4. Add alpha blocker
   or spironolactone (aldosterone receptor antagonist)
   or other diuretic
   Or beta blocker

Statins should be considered for all patients with a high risk of developing CVD.

Question 14

Give examples of ACEi and give the common side effects?

Answer 14

Dry cough

Hyperkalaemia and hyponatraemia