Pharmacology

Question 1

what is an inotropic drug?

Answer 1

affects contractility of the heart

-alters force/energy of muscular contractions

Question 2

what is a chronotropic drug?

Answer 2

affects HR

Question 3

outline the classes of anti-arrhythmic drugs

Answer 3

classified according to their effects on cardiac action potential

Question 4

outline cardiac action potential electrophysiology

Answer 4

Question 5

how do class 1 anti-arrhythmics work

Answer 5

work by blocking Na channels - slow depoalrisation & conduction

Question 6

give an example of class 1a anti-arrhythmic drug

Answer 6

Quinidine

v rarely used in UK due to adverse effects - may cause prolonged QT

Question 7

outline 2 class 1b anti-arrhythmic drugs

Answer 7

• lidocaine
• phenytoin

Question 8

outline a class 1c anti-arrhythmic drug

in who can this class not be given?

Answer 8

Flecainide

MARKEDLY depresses sodium entry into channels

In pts with CAD

Question 9

adverse affects of class 1?

Answer 9

• class 1 b&c–> neurotoxicity
• negatively inotropic
• N&V

Question 10

what are class 2 anti-arrhythmics?

Answer 10

beta-blockers

Question 11

how do beta blockers act? and effects?

Answer 11

• act to reduce sympathetic activity
• negatively inotropic & chronotropic
• act on AV node to reduce conduction
• act on SA node to reduce rate of spontaneous depolarisation

Question 12

adverse effects of beta blockers?

Answer 12

• postural hypotension
• bradycardia
• AV node block
• bronchoconstriction
• hypoglycaemia
• erectile dysfunction
• insomnia

Question 13

outline class III anti-arrhythmic drugs

Answer 13

amiodarone

sotalol

Question 14

mechanism of action of class III anti-arrhythmic drugs

Answer 14

block K channels - hence cause prolongation of refractory period

Question 15

adverse effects of amiodarone?

Answer 15

• thyroid dysfunction
• peripheral neuropathy
• photosensitivity
• lung fibrosis
• hepatitis /cirrhosis

Question 16

what are class 4 anti-arrhythmics?

Answer 16

Non-Dihydropyridine CCBs

Question 17

mechanism of action of non-dihydropyridine CCBs?

Answer 17

• reduce conduction through AV node
• negative inotropes
• negative chronotropes

Question 18

adverse effects of non-dihydropyridine CCBs

Answer 18

• bradycardia
• heart block
• constipation
• gum hyperplasia
• headaches, flushing, peripheral oedema
  
  • more common in dihydropyridines

Question 19

outline the classification of CCBs

Answer 19

• Dihydropyridines
  
  • amlodipine
  • nifedipine
• Non-Dihydropyridines
  
  • verapamil
  • diltiazem

Question 20

what are the different properties of the classes of CCB

Answer 20

• Dihydropyridine
  
  • anti-hypertensive properties
• Non-Dihydropyridine
  
  • anti-arrhythmic properties

Question 21

what is Digoxin?

Answer 21

• cardiac glycoside
• Na/K ATPase inhibitor

Question 22

mechanism of action of Digoxin?

Answer 22

• slows AV conduction
• positive inotrope

Question 23

adverse effects of digoxin?

Answer 23

• causes ECG changes
• toxicity may cause PR prolongation & lead to arrhythmias
• hypokalaemia potentiates its effects

Question 24

action of adenosine?

Answer 24

acts on SA node to reduce HR, and AV node to slow conduction

used primarily in SVT

Question 25

mechanism of action of atropine?

Answer 25

anti-cholinergic

Question 26

mode of action of aspirin?

Answer 26

* cyclo-oxygenase inhibitor * inhibits production of thromboxane A2 * reduces platelet aggregation

Question 27

mode of action of clopidogrel?

Answer 27

* ADP receptor antagonist * reduces platelet aggregation

Question 28

mechanism of action of nitrates?

Answer 28

* release NO to relax smooth muscle * venodilators

Question 29

outline cardioselective beta blockers

Answer 29

Betablockers Act Exclusively At Myocardium Betaxolol Acebutelol Esmolol Atenolol Metoprolol

Question 30

what is the stance of cardioselective b-blockers in pts with asthma

Answer 30

Cardioselective beta-blockers pose a lesser risk but this risk is invariably dose-dependent. **beta blockers should still be avoided in these patients.**

Question 31

diabetics and beta blockers consideration?

Answer 31

due to the risk of hypoglycaemia, beta blockers may mask the symptoms of a hypo in a diabetic

Question 32

what CCBs are used for treatment of stable angina? why do they work in preventing angina?

Answer 32

ALL They reduce cardiac rate, contractility and afterload and hence myocardial oxygen demand - preventing angina

Question 33

outline the main difference between dihydropiridine & non-duhydropyridine CCB in terms of where they act

Answer 33

* dihydro- relatively selective for the vasculature * non-dihydro- more selective for the heart * verapamil MOST cardioselective

Question 34

what must you not co-prescribe with beta blockers?

Answer 34

non-dihydropyridine CCB --\> may cause bradycardia, asystole etc