Hyper and Hypotension therapies

Question 1

What is the classification of hypertension and how do patients present?

Answer 1

> 140mmHg and/or 90mmHg

Asymptomatic presentation = compliance issues

Question 2

What is the aim of antihypertensives?

Answer 2

Reduce CO and TPR by targeting the vasculature

Question 3

What normally controls BP?

Answer 3

Baroreflex, ANS innervation to heart, sympathetic to vessels and RAAS

Question 4

What determines the choice of antihypertensive?

Answer 4

Age and genetics with gentics influencing most.

Question 5

What is the antihypertensive drug pathway?

Answer 5

<55yrs —> A —> // >55yrs —> C or D

—> A+C or A+D —> A+C+D —> Diuretics, alpha and beta blockers

Question 6

What is the mechanism of action of ACEi (A)?

Answer 6

e.g. lisinopril, enalapril
Decrease AngII for reduced vasoconstriction and aldosterone release = Reduce TPR and CO
Decrease degradation of vasodilator kinins = prolong dilation

Question 7

What are the s.e. of ACEi?

Answer 7

Dry cough as bradykinin enters lungs for bronchodilation and irritates nerve endings.
Sudden hypotension if used with diuretic

Question 8

How is ACEi used?

Answer 8

First line treatment for mild hypertension in young pts.

Question 9

What is the mechanism of action of ARBs (A)?

Answer 9

Ang receptor blockers e.g. irbesartans, losartan

Blocks AT1 receptors for vasodilation to reduce TPR and CO

Question 10

When is ARBs used?

Answer 10

If ACEi cannot be tolerated

Question 11

What is the mechanism of action of CCB (C)?

Answer 11

e.g. DHP, verapamil

Targets smooth muscle of arterioles to reduce TPR. Has no effect on heart, kidneys or venous vessles.

Question 12

When are CCB used?

Answer 12

To treat mild hypertension

May affect GIT activity

Question 13

What is the mechanism of action of diuretics (D)?

Answer 13

e.g. Thiazides = Na/Cl symporter, Furosemide (NKCC loop diuretic).
Work to affect the blood and CO by increasing water and Na excretion to reduce blood volume and CO.

Question 14

What is the long term effect of diuretics?

Answer 14

Arterial dilation results from the long term low TPR as Na depletion reduces intracellular Ca so smooth muscle cannot contract.

Question 15

Which are the best diuretics to use?

Answer 15

Thiazides > loop diuretics

Question 16

What are the side effects of diuretics?

Answer 16

Hypokalaemia due to the reduced Na `

Question 17

When is a diuretic used?

Answer 17

First line for mild hypertension

Question 18

How does a beta blocker affect hypertension?

Answer 18

e.g. propanolol, atenolol

Acts on symp NS to reduce HR, contractility, renin and CO.

Question 19

What are the side effects of beta blockers?

Answer 19

Cause bronchospasm if target beta2 in a pt with asthma
Long term use increases risk of DM
Exercise intolerance as blocking beta1 so no raise in HR

Question 20

When is a beta blocker used?

Answer 20

Usually avoided unless young female or stable on it

Question 21

How do alpha blockers affect hypertension?

Answer 21

e.g. prazosin, dozazosin. Works to block constriction in all vasculature to reduce TPR and CO

Question 22

What are the s.e. of alpha blockers?

Answer 22

Postural hypertension due to inability to constrict lower extremities.

Question 23

When are alpha blockers used?

Answer 23

Only in severe hypertension that is sudden or unmanagable or for pts with renal/cardiac problems.

Question 24

How are the antihypertensive drugs grouped?

Answer 24

Target RAAS: A or B
Targer smooth muscle: C or D
Choose one from each group or use all 3 if severe

Question 25

How is chronic hypertension that continues to get worse treated?

Answer 25

Not with an increase in dose but through combination therapy at low doses to reduce the toxic effects.

Question 26

What causes hypotension?

Answer 26

Haemorrhage, burns, anaphylatic or hypovolaemic shock.

Question 27

How is hypotension treated?

Answer 27

Sympathomimetics e.g. Ad to alpha receptors for vasoconstriction or beta receptors for increased HR = increases CO and BP
Can treat by treating the cause e.g. fluids, blood