Antihypertensive drugs

Question 1

explain the determinants of arterial blood pressure in terms of cardiac output

Answer 1

heart rate
* sympathetic & parasympathetic (vagus nerve)

stroke volume
* Filling pressure & contractility (sympathetic)

Question 2

Explain the determinants of arterial blood pressure in terms of peripheral vascular pressure

Answer 2

Neural
* sympathetic & parasympathetic NS
*for momoent to moment changes

Hormonal
* Renin-angiotensin-aldosterone system (RAS)
*longer term changes

Local transmitters
* Nitric Oxide (NO)

Question 3

Explain the determinants of arterial blood pressure in terms of blood volume

Answer 3

Volume
– Hormonal (RAS, ADH, ANP)

Question 4

How does the Renin-angiotensin system control Bp and volume

Answer 4

Kidneys detect changes in renal blood flow this aligns with the activation of the sympathetic nervous system

Response: produce more or less Renin

Renin binds to angiotensin precursor protein produced by the liver and enzymatically activates it to form angiotensin I

Angiotensin I is converted to angiotensin II by ACE forming a potent peptide at AT1 receptors

Aldosterone is produced to mediate sodium and water retention

Causing vasoconstriction at arterioles (angio-tensin)

Question 5

Describe the mechanisms of action for the main classes of thiazide diuretics

Question 6

Describe the mechanisms of action for the main classes of beta-adrenoreceptor blockers

Answer 6

Beta 1 adrenoreceptor blockers

decrease blood pressure by preventing increased heart rate and contractility

Question 7

Describe the mechanisms of action for the main classes of ACE inhibitors

Answer 7

inhibits action of angiotensin converting enzyme

prevents angiotensin 1 being converted to potent AT1 receptor ligand angiotensin 2

decreasing vasoconstriction

Question 8

Describe the mechanisms of action for the main classes of angiotensin I receptor blockers

Answer 8

Blocks AT1 receptor

Prevents activation and subsequent release of aldosterone

decreases vasoconstriction

Question 9

Describe the mechanisms of action for the main classes of alpha adrenoceptor blockers

Answer 9

Relaxes peripheral resistance vessels by preventing vasoconstrion (caused by symp NS) therefore decreasing PVR

decrease BP

Question 10

Describe the mechanisms of action for the main classes of calcium channel antagonists

Answer 10

Decreases the contractile force of the heart to pump blood into the vascular system by blocking Ca2+ entrance

Reduces peripheral vascular resistance

Reduce BP