ACS drugs

Question 1

main targets for CAD management (4)

Answer 1

supply - coronary blood flow, arterial oxygen content;
demand - HR, force of contraction

Question 2

main drug classes in CAD (6)

Answer 2

reduce cardiac workload (decrease myocardial O2 demand) - B-blockers, CCBs, other channel inhibitors, BP lowering (indirectly, effect afterload);
coronary vasodilators - nitrates, K+ channels openers (e.g.nicorandil)

Question 3

where are L-type Ca2+ Channels present and what is the effect of blocking them (3)

Answer 3

1. arterial smooth muscle - vasodilation
2. cardiac muscle - reduced force of contraction
3. cardiac pacemaker tissue - reduced heart rate/AVN block

Question 4

how does Ca2+ cause muscle contraction (mech)

Question 5

what are the 2 types of CCBs and examples

Answer 5

1. non-dihydropiridine (negative ionotropic), useful for arrythmias and angina, veramapil/ diltiazem
2. dihydropiridine (non-ionotropic), acts on smooth muscle to reduce BP - used for hypertension, little/no cardiac effect, amolodipine, nifedipine

Question 6

common adverse affects of CCBs (6)

Answer 6

negative ionotropic - slow HR, reduced contraction (may worsen heart failure);
non-ionotropic - headache (due to increased flood flow), flushing, peripheral oedema, reflex tachy (to counteract increased blood flow)

Question 7

what does ionotropic mean (in terms of the heart)

Answer 7

contractility - positive inotropy is an increase in contractility (contract with more force)

Question 8

verapamil vs diltiazem

Answer 8

verapamil - mainly cardiac affects; diltiazem - cardiac and vascular effects; choose appropriate drug depending on the action required

Question 9

high levels of what NTs (2) result in high mortality levels from heart disease

Answer 9

NA; adrenaline

Question 10

what does increased NA/adrenaline cause (cardiac + resp)

Answer 10

activates beta-receptors which act on cardiac tissue and pacemaker cells to increase force and rate of contractions (B1); acts of bronchial smooth muscle to dilate airways (B2)

Question 11

what is the effect of BBlockers

Answer 11

block beta-receptors so they cannot be stimulated by NA/adrenaline release -> stops increase in HR/contraction force; new BBs try to focus on just blocking B1 receptors so that lung function is not affected, otherwise it could be danger out to people with asthma

Question 12

commonly used BBs

Answer 12

non-specific: propanolol (worsens asthma);
cardioselective: atenolol, bisoprolol, metoprolol;
vasodilator activity: carvedilol, labetelol (alpha blocking properties, causes vasodilation)

Question 13

what conditions have BBs demonstrated a reduction in mortality in

Answer 13

ACS; MI; chronic heart failure; angina; AF; resistant HTN (small roll in HTN alone)

Question 14

adverse effects of BBs (4)

Answer 14

cardiac: bradycardia, HF initially worsens (start a low dose);
sympathetic blockade: bronchoconstriction, fatigue/feeling cold (due to decreased adrenaline)

Question 15

MOA of nitrates

Answer 15

nitrates -> increased nitric oxide -> increased cGMP -> increased dephosphorylation of myosin light chain, decreased Ca2+ influx into cell -> relaxation of vascular smooth muscle (vasodilation)

Question 16

effects of nitrates (3)

Answer 16

arterial dilation: improves coronary supply by vasodilating coronary artery to reduce BP;
venous dilation: decreased preload and stretching of the heart (decreased venous return to heart), Decreased pressure in ventricles (Especially diastolic wall pressure)

Question 17

adverse effects of nitrates (4)

Answer 17

hypotension, reflex tachy, headaches, flushing

Question 18

what are nitrates used for

Answer 18

symptom relief in ischaemic chest pain; relief of acute heart failure (high dose IV required)

Question 19

commonly used nitrates (2)

Answer 19

glyceryl trinitrate (GTN) - sublingual or spray usually (oral is broken down by liver), rapid relief but short acting;
isosorbide mononitrate - oral, OD, prevention of angina pain

Question 20

specialist drugs for angina treatment (3)

Answer 20

nicorandil (K+ channel opener, nitrate action); ranolazine (late Na+ current inhibitor); ivabradine (sinus node inhibitor, slows HR, blocks conduction)

Question 21

when to use CCBs

Answer 21

uncontrolled hypertension; vasoplastic/mixed angina, MI without HF

Question 22

when to use BBs

Answer 22

previous MI or HF

Question 23

what are the key targets for hypertension

Answer 23

cardiac output (decrease - slow pumping); vascular resistance (vasodilation to reduce resistance, vol of blood is reduced)

Question 24

main drug targets in hypertension (and drug types)

Answer 24

intravascular volume - diuretics, thiazides;
sympathetic tone - alpha and B-blockers;
peripheral arteries - CCBs (vasodilation);
neuroendocrine mediators of BP (block) - ACEi, ARBs, renin inhibitors

Question 25

renin-angiotensin-aldosterone system pathway

Answer 25

angiotensin – (rennin, causes Na+ depletion, decreaded BP and increased B1 adrenogenic symp stimulation)–> angiotensin I –(ACE)–> angiotensin II, causes vasoconstriction, ADH release, increased symp stimualtion —-> aldosterone release, causes salt and water retention

Question 26

examples of ACE inhibitors

Answer 26

ramipril, captopril, enalapril

Question 27

when to use ACE inhibitors

Answer 27

first line for hypertension UNLESS >55yro or african heritage

Question 28

what should be given to those who cannot take ACE inhibitors (>55yro, african heritage)

Answer 28

CCBs, Angiotensin II blockers (2nd line)

Question 29

physiological effects (+side effects) of starting an ACE inhibitor + how to ensure safety (4)

Answer 29

drops BP (give small dose, check not too volume depleted); worsens renal function (check U&Es after a week); retains K+ (stop K+ supplements or K+ sparing diuretics); causes cough and other allergies

Question 30

examples of angiotensin II blockers

Answer 30

lostartan; irbestartan

Question 31

types of diuretics (4)

Answer 31

loop; thiazides; thiazide-like-diuretics; potassium-sparing

Question 32

loop diuretics - use, effectiveness, examples

Answer 32

heart failure; high efficacy, 25% of sodium load can be excreted (used in renal impairement), IV works within 30 min - 1h, Used orally for long term 1/day in morning; Furosemide, bumetanide

Question 33

thiazide diuretics - use, examples

Answer 33

hypertension; Bendroflumethiazide

Question 34

thiazide-like- diuretics - use, effectiveness, examples

Answer 34

hypertension; Only excrete 5-10% of sodium load, Ineffective if GFR is under 30 and should be avoided; indapamide

Question 35

K+ sparing diuretics - use, effectiveness, examples

Answer 35

heart failure, hypertension; <5% sodium load excreted
Used in combination with more effective diuretics; spironolactone

Question 36

side effects of diuretics and how to ensure safety

Answer 36

Hypovolaemia, dehydration, hypotension (affects renal function); Electrolyte imbalance - Low K+, High urea;
Monitor BP, urine output, body weight; Check electrolytes regularly if on high dose

Question 37

HTN treatment plan (4)

Answer 37

1. ACEi/CCB (if not tolerated)
2. ACEi + CCB
3. ACEi + CCB + thiazide like diuretic
4. resistant hyper tension, continue as above + consider further diuretic + seek specialist help

Question 38

contraindications for ACEi

Answer 38

pregnancy (affects growth); african heritage; >55yro; HOCM; renal impairment