Hypertension - Howlett 1

Question 1

Primary hypertension

Answer 1

High blood pressure
Very common
Causes mostly unknown (obesity, inactivity, smoking, stress)
Asymptomatic until damage to heart, brain, retina etc

Question 2

Risk factors of hypertension

Answer 2

Age, family history, obesity, inactivity, smoking, stress

Question 3

Blood pressure control mechanisms

Answer 3

SNS (fast controlling)
Renin-angiotensin system (RAS): longer term control
Affect cardiac output and peripheral resistance

Question 4

Renin-angiotensin system

Answer 4

Renin/Angiotensin increase Na retention, which increases plasma volume
This increases arterial pressure

Question 5

Agents to treat hypertension

Answer 5

1. Diuretics
2. Drugs that affect the SNS
3. Vasodilators
4. Drugs that affect the RAS

Question 6

Diuretics

Answer 6

Act on cells in the renal tubule to promote diuresis and naturiesis
Include: Loop, Thiazide and Potassium sparing diuretics
Deplete Na stores in body causing vascular smooth muscle to become less stiff
Initial drop in BP due to lower blood volume and reduced CO
Eventually CO returns to normal but peripheral resistance is lower

Question 7

Loop diuretics

Answer 7

Inhibit Cl/K cotransporter in loop of henle

Question 8

Thiazide diuretics

Answer 8

Inhibit Na channel and increase Na and water in the lumen of the distal tubule
Mainly used in hypertension

Question 9

Potassium sparing diuretics

Answer 9

Inhibit K/Na exchanger in the collecting duct
Must be used with other diuretics because they cause too much K is being lost as exchanger is trying to absorb Na
Mainly used in hypertension

Question 10

Drugs affecting the SNS

Answer 10

Act at specific sites in the SNS and classified based on site

Question 11

Centrally acting drugs (SNS)

Answer 11

Clonidine, methyldopa
Decrease SNS outflow centrally, act at the BP control centre in the brain to reduce BP
Can cause sedation
Methyldopa is bad for pregnancy

Question 12

Beta-blockers

Answer 12

Propranolol, metoprolol
Short term: decrease HR and reduce force of contraction which reduced CO and decreases BP
Long term: decrease renin release - lower angiotensin II and aldosterone

Question 13

Alpha1-blockers

Answer 13

Prazosin
block alpha1 receptors on vascular smooth muscle cells
Blocks the effects of the SNS on blood vessels
Causes vasodilation and reduces BP
Can cause orthostatic hypertension

Question 14

Vasodilators

Answer 14

Ca channel blockers

Question 15

Ca channel blockers

Answer 15

Nifedipine, diltiazen and verapamil

Block influx of CA and contraction in vascular smooth muscle

Question 16

Nifedipine

Answer 16

Act on blood vessels only

Ca channel blockers

Question 17

Diltiazem

Answer 17

+ verapamil
Act on heart and blood vessels
Treat angina and arrhythmias

Question 18

Verapamil

Answer 18

+diltiazen
Act on heart and blood vessels
Treat angina and arrhythmias

Question 19

OTHER direct vasodilators

Answer 19

Hyrdalazine, sodium nitroprusside, minoxidil

Question 20

Drugs that affect RAS

Answer 20

ACE inhibitors

Angiotensin II receptor blockers

Question 21

ACE inhibitors

Answer 21

Captopril
Inhibit formation of angiotensin II from angiotensin I by inhibiting ACE
Do not take during pregnancy

Question 22

Angiotensin II receptor blockers of RAS

Answer 22

Losartan
Block receptors for angiotensin II, causing vasodilation and decrease in BP
Block of receptors on adrenal gland causes decrease of aldosterone release which leads to decrease in Na and water retention

Question 23

Polypharmacy

Answer 23

Multiple agents needed to control BP