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Flashcards in Cardio Deck (57):
1

How does botulinum toxin work?

It breaks up the SNARE proteins and thus prevents vesicle fusion with the membrane

2

How do anticholinesterases work?

Inhibits the breakdown of cholinesterase (ACh) and thus increases its concentration in the synapse

3

What are AChE used to treat?

Myasthenia gravis

4

What is used to diagnose myasthenia gravis and what is used to treat it?

Endrophonium to diagnose.
Neostigmine/Pyridostigmine to treat

5

What is donepazil?

AChE which can enter the CNS - used for alzhiemers

6

What do ANS muscurinic agonists cause

SLUDS (salivation, lacrimation, urination, defecation, sweating) + bronchoconstriction and vasodilation

7

How do cocaine and tricyclic anti-depresants work?

They bind to the NA re-uptake pathway increasing NA in the synapse

8

MOA of MAO

MAO breaks down NA into its metabolites, by inhibiting its action one can increase the amount of NA being repackaged into vesicles for release

9

What are 3 indirectly acting sympathomimetics?

Amphetamine, Ephedrine, Tyramine.

10

How d indirectly acting sympathomimetics work?

They are taken up via the NA reuptake pathway. They act on the vesicles to cause NA release into the cell which can then diffuse into the synapse. They essentially induce non calcium driven, non excocytotic NA release.

11

Selective B1 antagonists

Metroprolol and Atenolol

12

Partial non selective B1 and B2 antagonist

Pindolol

13

Non selective B antagonists

Propanolol/Timolol

14

Which B receptor is present on the heart?

B1

15

Name 3 contraindications for B antagonists

Asthma, Diabetes, AV block

16

Why are B blockers useful in angina

Slow down conduction rate/heart rate and allow more filling during diastole.

17

Side effects of B antagonists

Reflex a1 adrenoceptor constriction, blockade of dilatory B2 dilatory adrenoceptors. Fatigue, bronchoconstriction

18

Where do B blockers primarily act on the heart?

On the SA and AV nodes

19

Why are b blockers useful in arrhythmia?

They decrease sinus rate, conduction velocity and aberrant pacemaker activity

20

Name a selective B1 agonist

Dobutamine

21

Why should dobutamine only be used for a short time?

It increases the overall work of the heart - in the long term it may put too much strain on the heart and cause damage

22

Where to phosphodiesterases act?

They breakdown cAMP into AMP, the reduction of cAMP means that PKA cannot activate which in turn cannot phosphorylate the calcium channels and drive an influx this decreases contractility etc

23

Name a phosphodiesterase inhibitor what does it do?

Amrinone - inhibits the action of phosphodiesterase which breakdown cAMP into AMP, the reduction of cAMP means that PKA cannot activate which in turn cannot phosphorylate the calcium channels and drive an influx this decreases contractility etc. Without phosphodiesterase this process cannot continue and the calcium channel will remain open

24

Describe 2 mechanisms by which B1 receptors stop responding to B1 agonists

1. Reduced B1-adrenoceptor expression (i.e. less receptors to bind to)
2. Impaired B1-adrenoceptor coupling (i.e. even after binding no intracellular changes are driven.

25

On what receptors does Phentolamine act and how?

Acts on a1 and a2 adrenoceptors, it is an antagonist

26

What receptors doe Phenylephrine and Prazosin act

a1 recptors
Phenylephrine = agonist (nasal decongestant)
Prazosin = antagonist (used in hypertension)

27

Describe the process of angiotensin II production:

Sympathetic input causes the release of renin. Renin catalyses the conversion of angiotensinogen into angiotensin I. Angiotenin I is then converted into ANGII by the angiotensin converting enzyme.

28

List 3 roles of ANGII

Promotes cell growth
Vasoconstriction
These 2 are caused by its action on AT 1 receptors

Aldosterone production (which leads to salt and water retention)

29

What are the class of drugs which inhibit angiotensin II production known as and what is the suffix given to the drug class?

ACE inhibitors
Prills (Catopril, Enalopril, Perindopril, Ramipril)

30

What are some side effects of ACE inhibitors?

First dose hypotension (dangerous in the elderly)
Dry cough (linked to bradykinin)
Loss of taste
Hyperkalaemia (thus administered with potassium losing diuretic - thiazide)
Acute renal failure
Rash
Itching
foetal malformation (it is teratogenic)

31

What are the class of drugs which act on the angiotenisin receptor called?

Sartans (Losartan/Candesartan)

32

Contraindications for ACE inhibitors and angiotensin receptor antagonists

Pregnancy, bilateral renal stenosis, angioneurotic oedema

33

Which channels to calcium channel blockers act on?

L-type Ca2+ channels

34

What do calcium channel blockers do?

Reduced Ca2+ available for intitiation of action potential, thus they increase conduction velocity and length of refractory period.

35

Where specifically in the heart do Ca2+ blockers act?

The SA and AV node

36

What calcium channel blockers used to treat?

Hypertension -
Tachycardias and tachyarythmias
Angina - Slows down heart rate = longer diastole (mostly verapamil and Diltiazem)

37

Which group of calcium channel blockers reduce vascular resistance?

Dihydropyridines (Felodipine/Nifedopoine)
- Reduce afterload (are vascular selective)

38

What are verapamil and Diltiazem?

Calcium channel blockers which act both on vasculature and on the cardiac muscle.
Verapamil - significant effects on cardiac muscle
Diltiazem - Less pronounced effect on cardiac cells

39

Side effects of calcium channel blockers?

Oedema, flushing, headache, bradycardia,

40

Contraindications for calcium channel blockers?

Beta blockers

41

Name the 3 class 1 antidysrhythmics?

1a - Quinidine
1b - Lidocaine
1c - Flecianide

42

What is Quinidine and how does it act?

Quinidine is a class 1a antidysrhythmics, it is a moderate Na+ block and prolongs repolarization increasing the ERP

43

What is Lidocaine and how does it act?

Lidocaine is a class 1b antidysrhythmics, it is a mild Na+ block and shortens depolarization and decreases the ERP

44

What is Quinidine and how does it act?

Quinidine is a class 1a antidysrhythmic, it is a moderate Na+ block and prolongs repolarization increasing the ERP

45

What is Lidocaine and how does it act?

Lidocaine is a class 1b antidysrhythmic, it is a mild Na+ block and shortens depolarization and decreases the ERP

46

What is Flecainide and how does it act?

Flecainide is a class 1c antidysrhythmic, it markedly blocks the Na+ chanels and results in the same repolarization time with no effect on the ERP.

47

Name the 3 class 1 antidysrhythmics?

1a - Quinidine
1b - Lidocaine
1c - Flecianide

48

When are 1a antidysrhythmics used?

Ventricular arrhythmias
prevention of paroxysmal recurrent atrial fibrillation (triggered by vagal overactivity)

49

When are 1b antidysrhythmics used?

ventricular tachycardia

50

When are 1c antidysrhythmics used?

prevents paroxysmal atrial fibrillation
treats recurrent tachyarrhythmias of abnormal conduction system.
contraindicated immediately post-myocardial infarction.

51

When are 1c antidysrhythmics used?

prevents paroxysmal atrial fibrillation
treats recurrent tachyarrhythmias of abnormal conduction system.
contraindicated immediately post-myocardial infarction.

52

what are the class 2 antidysrhythmics?

B-blockers

53

What are the class 3 antidysrhythmics?

K+ channel blockers

54

Name a class 3 antidysrhythmic

Amiodarone

55

How does Amiodarone act?

It slows phase 3 repolarization and hence prolongs a cardiac action potentail (i.e. it slows the heart)

56

What are the class 4 antidysrhythmics?

Calcium channel blockers

57

Glycosides

aa