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Pharmacology > Cardiovascular > Flashcards

Flashcards in Cardiovascular Deck (36):
1

Positive inotropes

Increase strength of contraction

2

Negative inotropes

Decrease strength of contraction

3

Luisotrope

Strength of relaxation

4

Positive chronotrope

Increase heart rate

5

Negative chronotrope

Decrease heart rate

6

What is rate determined and controlled by?

Cv centre in medulla oblongata

7

Controlling tachyarrythmias?

Sympathetic antagonists or parasympathetic agonist

8

Class 1 antidysrhythmics

Block na channels
Slows depolarisation of myocytes
1a 1b and 1c classes
Use dependent na channel blockade- bind to cells that are firing off the most, leave normal cells alone

9

Class 1a example

Quinidine
Used to convert atrial fibrillation in horses
Oral admin, highly protein bound
Mildly vagolytic- increases heart rate and conduction

10

Class 1b example

Lidocaine
IV admin- 1st pass metabolism
Ventricular tachycardia- prevent premature beats
Hypotension at toxic levels

11

Class 1c example

Flecainide
Strong
Slows depolarisation and conduction through His Purkinje system
Ventricular arrhythmia

12

Class II antidysrhythmics

Beta blockers
Slows pacemaker production and conduction
Stops calcium phosphorylation- no contractions
Not good with patients with heart failure- vasodilation, negative lusitrophy

Eg Atenolol

13

Class III antidysrhythmics

Block k channels- slows repolarisation
Prolong QT interval

Eg sotalol
Can cause hypotension and bradycardia

14

Class IV antidysrhythmics

Block ca channels
Ca needed for pacemakers to depolarise
Slows conduction through SAN and AVN
good for supra ventricular tachycardia
Also are vasodilator

Eg Diltiazem
Oral admin- 1st pass met, also parentreal admin

15

Miscellaneous antidysrhythmics
Cardiac glycoside

Digoxin
Negative chronotrope without negative inotropes
Decreases heart rate without decreasing strength of contraction

Vagomemimetic- mimics parasympathetic
Inhibits na removal from cell
Slows conduction through AVN
Allows ventricles enough time to fill

Oral admin- highly protein bound

16

Sympathomimetics
Treating bradyarrhythmias

Beta one agonist- Dobutamin
Increase contractility, can cause tachycardia

Beta two agonist- terbutaline
Increase heart rate, bronchodilator (reap distress)

17

Anticholinergics
Treating bradyarrhythmias

Muscurinic antagonist
System is inhibition of parasympathetic ns
Short term use
Eg Atropine

18

PDE III inhibitor

Eg Pimobendan
Increases intracellular cAMP and increases contractility
Activates PKA to phosphorylate ca channels- ca influx- contract

Vasodilation to decrease after load
Prevent phosphorylation of MLCK in vascular smooth muscles

19

Negative inotropes??
Decrease strength of contraction?

Sympathetic antagonist
Cholinergics
Calcium channel blockers

20

When would you want to reduce preload?

Congestive heart failure
Can't cope with volume

21

When would you want to reduce afterload?

Forward heart failure
Allows more blood to flow out

22

When would you want to increase local perfusion?

Reduce compensatory vasoconstriction of non essential blood vessels

23

When would you want to decrease systemic arterial pressure?

Hypertension

24

Endogenous mechanisms to alter blood flow

Intrinsic- metabolic/paracrine (no)

Extrinsic- baroreflex, RAAS, pituitary ADH, hypothalamus thirst centre

25

Direct vasodilator?

Nitrates
Ca Channel blockers
PDE v inhibitors

26

Nitrates

Peripheral vasodilation- nitrous oxide
NO-cGAMP- activates k channels to hyperpolarise cell
Activates MLCP to dephosphorylates MLC-relaxation
Blocks ca entry, no contraction

Eg nitroglycerin
Metabolised to NO
Potent vasodilator , used percutaneously. Emergency situ- rapid

27

Ca channel blockers- vasodilation

(Also class 4 antidysrhythmics)
Amlodipine
Really common
No calcium, no contraction, blood vessels relax and dilate
May cause hypotension and reflex tachycardia

28

What is reflex tachycardia?

Cv centre has reset blood pressure at regency point higher than normal due to ongoing hypertension.
When BP is lowered due to drugs, it detects a lower BP than at reference point and will work to increase it and increase heart rate

29

Hydralazine

Uncertain method or action
Arteriodilator
Big drop in afterload
Reflex tachycardia

30

PDE V inhibitor

Sildenafil
Inhibits breakdown of cGAMP
activates protein kinase G
Activates MLCP- dephosphorylates MLC
Relaxation
Vasodilation

31

Indirect vasodilators?

Sympathetic antagonist
ACE inhibitors
ANGII receptor antagonists
Aldosterone antagonist
Anti diuretics

32

Alpha one adrenoreceptor blockade

Blood vessel vasodilation
Not selective- can happen at any point
Not really used
Eg Prazosin

33

ACE inhibitors

Vasodilation and decrease blood volume
Blocks RAAS cascade
Activates in liver, renally excreted

Eg
Ramipril
Benazepril (renal compromised patients, excreted in bile)






34

ANGII inhibitors

Will block all formation of ANGII
Eg Telmisartan
Oral admin, highly protein bound, met in liver, exc in bile and urine

35

Aldosterone antagonists

Decrease na and k retention
Reduces cardiac remodelling
(Decreasing k can lead to bradycardia)

Eg spironolactone
Oral admin, high protein bound

Cardalis- benazepril+spironolactone

36

Golden quadruple treatment for heart failure

ACE inhibitor- benezepril
Aldosterone inhibitor- spironolactone
Diuretic- furosemide
PDE III inhibitor- pimobendan