Antihypertensive Drugs

Question 1

Why treat hypertension?

Answer 1

Very common, >50% of elderly, major risk factor for stroke and ischaemic heart disease e.g MI

Question 2

At what point do you treat HTN?

Answer 2

When systolic is over 160 or diastolic is over 100.

Question 3

What is the equation for blood pressure?

Answer 3

BP = CO X TPR

Question 4

What do diuretics do?

Answer 4

Act on kidneys to increase diuresis. Increase sodium excretion. Water loss follows and so plasma volume is decreased - decrease in TPR and CO.

Question 5

What is the site of action for thiazide diuretics?

Answer 5

Distal convoluted tubule in the kidneys.

Question 6

What is the action of thiazide diuretics?

Answer 6

Inhibit sodium and chloride co-transport. Increase renin release.

Question 7

What are examples of thiazide diuretics?

Answer 7

Chlorothiazide, Hydrochlorthiazde, Bendrofluazide. Chlorthalidone, Metolazone.

Question 8

What are the adverse effects of thiazide diuretics?

Answer 8

More frequent urination, high safety, low profile side effects.

Question 9

What is the site of action for loop diuretics?

Answer 9

Loop of Henle in the kidneys.

Question 10

When are loop diuretics used?

Answer 10

Very potent. Reserved for patients with renal insufficiency, resistant HTN or heart failure.

Question 11

What are examples of loop diuretics?

Answer 11

Furosemide, Bumetanide.

Question 12

What are the 3 classes of vasodilator drugs?

Answer 12

Calcium antagonists, A-Blockers, Angiotensin Antagonists.

Question 13

What are the actions of vasodilator drugs?

Answer 13

Acts directly on the smooth muscle cells of arteries and arterioles. Lowers the intracellular calcium concentration which causes muscle cell relaxation. Results in vasodilation.

Question 14

What do Calcium Antagonists do?

Answer 14

Block calcium entry through voltage operated calcium channels in arterial smooth muscle cells.

Question 15

What are Nifedipine, Amlodipine and Nicardipine examples of?

Answer 15

Calcium antagonists - Dihydropyridines.

Question 16

What are the side effects of calcium antagonists?

Answer 16

Flushing and ankle oedema.

Question 17

What do A-Blockers do?

Answer 17

Drugs used for HTN are selective blockers of a1-adrenoreceptors. Prevent vasoconstrictors action of noradrenaline.

Question 18

What are the examples of A-blockers?

Answer 18

Doxazosin, Terazosin, Prazosin.

Question 19

What are the adverse effects of a-blockers?

Answer 19

Postural hypotension - dizziness, light headedness. Possible severe hypotension after first does but generally well tolerated.

Question 20

Give 2 examples of beta blockers.

Answer 20

Atenolol, Metoprolol.

Question 21

What do B-Blockers do?

Answer 21

Bind to and block B1-adrenoreceptors in the heart. Block action of noradrenaline. Initial effect = decrease rate and force of heart beat and decrease CO.

Question 22

What are the adverse effects of B-blockers?

Answer 22

Cold hands, Fatigue. Can provoke asthma attacks. Heart failure.

Question 23

Give example of ACE inhibitors.

Answer 23

Enalapril, Captopril, Lisinopril, Ramipril.

Question 24

What do ACE inhibitors do?

Answer 24

Prevent conversion of Angiotensin I into Angiotensin II. Causes vasodilation. Decreases plasma volume.

Question 25

What are the adverse effects of ACE inhibitors?

Answer 25

Dry cough, hypotension.

Question 26

Give examples of angiotensin II receptor antagonists.

Answer 26

Losartan, Candesartan, Eprosartan, Valsartan

Question 27

What do angiotensin antags do?

Answer 27

Block the action of angiotensin II at its receptors - causing vasodilation. Used in combination or as an alternative to ACE inhibitors.

Question 28

What are the side effects of angiotensin antags?

Answer 28

Headache, dizziness.