CVS drugs Flashcards
What are ACE inhibitors used for?
Heart failure and hypertension
Example of ACE inhibitor
Perindopril
What do ACE inhibitors do for the heart?
Decrease blood pressure
= Reduce afterload of heart
Decrease blood volume
= decreased preload
When is angiotensin 2 receptor blocker used?
Heart failure
Hypertension
if cant tolerate ACE inhibitors
ARB exambple
Losartan
Diuretics used
Hypertension and Heart failure
Loop diuretics especially useful in congestive HF
Example of diuretic
Furosemide
Reduces pulmonary and peripheral oedema (decreased blood volume)
Ca2+ channel blockers example
Dihydropyridine act on smooth muscle cells (not for arrythmias)
eg Amlodipine, nicardipine
How do dihydropyridine Ca2+ blockers work?
Decrease peripheral resistance
Decrease arterial BP
Reduce afterload
Other type Ca2+ blockers
Verapamil and Diltiazem reduce force of contraction
When are Ca2+ blockers used?
Hypertension, angina, coronary spasm, SVT
What are positive inotropes?
Increase contractility and cardiac output
eg cardiac glycosides and B adrenergic agonists
Cardiac glycosides example and explain
Digoxin (from foxglove)
Blocks Na+K+ATPase = rise in Na+ intracellular
What occurs when cardiac glycoside blockes Na+K+ATPase
Rise in intracellular Na+ (pump pumping it out)
Decreased concentration gradient for secondary active transport of Ca2+ out of cell
Na+Ca2+ exchanger has less activity
Increase Ca2+ intracellular concentration
What does an increase in intracellular Ca2+ mean?
More Ca2+ stored in ER
Increase force of contraction
What else do cardiac glycosides do?
Increase vagal activity
Slows AV conduction
Slows HR
When are cardiac glycosides used?
Heart failure with arrhythmia (eg atrial fibrillation)
B adrenoreptor agonists example
Dobutamine
What does dobutamine do?
Selective for B1 adrenoreceptors
Stimulates these in SA and AV node on ventricular myocytes
= increase contractility and HR
When is dobutamine used?
Cardiogenic shock
Acute but reversible heart failure (eg after heart surgery)
How should you treat heart failure?
NOT with cardiac glycosides
These relieve symptoms but just make heart work harder and not good in long term
reduce workload with ACEi, ARBs, diuretics, Beta blockers
What are nitrates used for?
Angina (from ischaemia)
What do nitrates do?
React with thiols (SH groups)
Nitric oxide released (when NO2 is reduced)
= vasodilation
What effect does nitrates mostly have?
VASODILATION ON VEINS
Examples of organic nitrates
GTN spray (quick, short) Isosorbide (longer acting)
How does nitric oxide cause vasodilation
Nitric Oxide activates guanylate cyclase
Increase cGMP
Lower intracellular Ca2+
Relaxation of smooth muscle
Why do organic nitrates act on veins?
Less endogenous NO already there?
so has a stronger effect
Primary and secondary action NO
Primary:
vasodilation of venous system = lower venous pressure and preload
(heart fills less, force of contraction reduced, lowers O2 demand)
Secondary:
acts on collateral coronary arteries
improves O2 delivery to ischaemic myocardium
What do organic nitrates not do?
THEY DO NOT Dilate arterioles
Treating angina summary
Reduce work load:
Organic nitrates
B adrenoreceptor blockers
Ca2+ channel antagonists
Improve O2 supply:
Ca2+ channel antagonists
Which conditions increase risk of thrombus?
Atrial fibrillation
Acute MI
Mechanical prosthetic valves
Antithrombotic drug types
Anticoagulants - prevent venous thromboembolism
Antiplatelets - prevent platelet aggregation and thrombus formation
Anticoagulants
Heparin/fractionated heparin (inhibits thrombin)
Warfarin (antagonises Vit K)
DOACS (eg Dabigatran inhibit factor 10/thrombin)
Antiplatelet drugs
Aspirin
Clopidogrel
used after MI to prevent thrombus
