Hypertension Drugs

Question 1

What does blood pressure have to be to be treated for hypertension?

Answer 1

160/100
or
140-159/90-99
in people with known cardiovascular disease, diabetes or organ damage

Question 2

What two things must be reduced to lower blood pressure?

Answer 2

cardiac output ( by reducing heart rate, stroke volume, plasma volume)
and
total peripheral resistance (by dilating arteries)

Question 3

How do diuretics lower BP?

Answer 3

• reduce plasma volume then gradually TPR
• increase sodium excretion and water follows
• reduces plasma volume
• reduce cardiac output

Question 4

In brief how do vasodilators reduce BP?

Answer 4

directly lower TPR

Question 5

In brief how do B-blockers reduced BP?

Answer 5

reduce cardiac output and kidney renin secretion

• bind to and block B- adrenoceptors in the heart
• block action of noradrenaline released from sympathetic nerves and circulating adrenaline

Question 6

How do ACE inhibitors lower BP?

Answer 6

inhibit endogenous vasoconstrictor production

• prevent conversion of angiotensin I to angiotensin II
• stimulates aldosterone secretion (which inhibits salt and water excretion )
• causes vasodilation
• reduces plasma volume

Question 7

How do a-blockers reduce BP?

Answer 7

• reduce TPR by inhibiting noradrenaline actions
• drugs used for hypertension are selective blockers of a-adrenoceptors
• prevent vasoconstriction action of endogenous noradrenaline

Question 8

How do angiotensin antagonist reduce BP?

Answer 8

Reduce TPR by inhibiting angiotensin action

Question 9

Where do thiazide diuretics have their action?

Answer 9

block sodium, chloride pumps in distal convoluted tubule

Question 10

Where do loop diuretics have their action?

Answer 10

block sodium, potassium and chloride pump in loop of Henle

Question 11

Thiazide diuretics are moderately potent and reduce both systolic and diastolic pressure. What do they increase?

Answer 11

renin release - may counteract on blood pressure

Question 12

Name 5 examples of thiazide diuretics.

Answer 12

derived from benzothiadiazide
- chlorothiazide 
- hydrochlorothiazide
- bendrofluazide
thiazide like structures 
- chlorthalidone 
- metolazone

Question 13

Examples of thiazide diuretics are chlorothiazide, hydrochlorothiazide and bendrofluazide. what are the adverse effects of these?

Answer 13

• more frequent urination
• low profile of side effects
  high safety

Question 14

Loop diuretics are very potent and no more effective than thiazides at reducing BP. Who are they reserved for?

Answer 14

use in patients with

• renal insufficiency
• resistant hypertension
• heart failure

Question 15

What are the actions of vasodilators?

Answer 15

• act directly on the smooth muscle cells of arteries and arterioles
• lower intracellular calcium concentration
• cause muscle cell relaxation
• results in vasodilation

Question 16

What are the actions of calcium antagonist such as dihydropyridines and benzothiazepine?

Answer 16

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

Question 17

Name some examples of the calcium channel blockers such as duhdropyridines and benzothiazepines.

Answer 17

dihydropyridines 
- nifedipine 
- amlodipline 
- nicardipine 
benzothiazepine 
-diltiazem

Question 18

What are the differences between dihydropyridines such as nifedipine, amlodipine and nicardipine compared with benzothiazepines such as diltiazem ?

Answer 18

Dihydropyridines - highly selective for smooth muscle but affect most smooth muscle
benzothiazepine - also blocks calcium channels in conducting thissue of the heart

Question 19

What are the adverse of calcium channel blockers?

Answer 19

• flushing
• ankle oedema
  diltiazem
• cardiac depression
• interaction with B-blockers

Question 20

a-blockers such as doxazosin, terazosin and prazosin are relatively well tolerated but what are some of the adverse effects?

Answer 20

• postural hypotension (dizziness, light headed)

- possible severe hypotension after first dose

Question 21

Examples of beta blockers are atenolol and metoprolol.

What are their initial and continued effect?

Answer 21

Initial effect 
- reduce rate and force of heart beat 
- decrease cardiac output 
Continued treatment 
- cardiac output returns to normal but BP remains low (TPR reset at lower volume )

Question 22

Examples of beta blockers are atenolol and metoprolol. What are the adverse side effects of these drugs?

Answer 22

• cold hands
• fatigue
• can provoke asthma attack in asthmatic
• heart failure
• conduction block in heart
• may affect blood lipids

Question 23

Most ACE inhibitors end in pril such as captopril, enalapril and Ramipril. What are the adverse effects of these drugs?

Answer 23

• dry cough
• hypotension initially, especially if given with diuretic
• these effects wear off with time

Question 24

Angiotensin II receptor antagonist work by blocking the action of angiotensin II at its receptors. What are examples of these drugs?

Answer 24

• Losartan
• Candesartan
• Eprosartan
• Valsartan

Question 25

Why are angiotensin II receptor antagonist used?

Answer 25

• in combination with ACE inhibitors to improve mortality and morbidity
• alternative to ACE inhibitors in intolerant patients

Question 26

When choosing which drug to prescribe as suggested by pharmacology thiazide is given and if ineffective add ACE inhibitor or calcium channel blocker. B-blockers used to be first line choice. why are they not now?

Answer 26

• less effective at reducing risk of stroke

- more side effects

Question 27

What do NICE guidelines suggest when prescribing choice of drug?

Answer 27

start with ACE inhibitor if under 55

• add calcium channel blocker if needed and then diuretic if further needed.
• if over 55 or black or Caribbean family start with calcium channel blocker and then add ACE if needed.