ACS & AMI - Therapy Flashcards
What are the aims of drug therapy for ACS and AMI?
2
- increase myocardial O2 supply (vasodilation)
- decrease myocardial O2 demand (HR, BP, contractility, preload/afterload)
In patients with STEMI, what would be the indicated treatment if they are unable to get to a cath lab in <2hrs?
thrombolysis
Briefly outline the mechanism behind thrombolytic agents.
plasminogen is converted to plasmin which lyses fibrinogen and fibrin contained in clot
Outline the main fibrin-specific thrombolytic agents.
How do these agents work?
(3)
alteplase
tenecteplase
reteplase
catalyse conversion of plasminogen to plasmin
Name a thrombolytic agent which is non-fibrin-specific.
How does this agent work?
streptokinase - catalyses systemic fibrinolysis
What is a complication associated with streptokinase?
anaphylaxis
What are some contraindications to thrombolysis?
4
- prior intercranial haemorrhage (ICH)
- known cerebral aneurysm
- mets in the brain
- stroke < 3m
If there is no evidence of STEMI, what would be the medical treatment for acute ACS/NSTEMI?
BATMANS
Beta-blocker Aspirin Ticagrelor (dual antiplatelet) Morphine (analgesia) Anticoagulant (e.g. LMWH, fondaparinux) Nitrate (e.g. IV GTN) Statin
What drug is usually prescribed only to patients going for a PCI?
How does this drug compare to clopidogrel?
prasugrel
inhibits ADP receptor more rapidly.
What secondary measures are taken to prevent future risk from NSTEMI/ACS?
7 A’s
- Aspirin
- another antiplatelet (e.g. clopidogrel)
- atenolol (b-blocker)
- ACE inhibitor (e.g. ramipril)
- Anticoagulant (e.g. heparin, fondaparinux)
- atorvastatin (statin)
- aldosterone inhibitor (e.g. epleranone)
What is the daily dose of aspirin often prescribed to patients at risk of further AMI/ACS?
75mg
Aspirin is a potent inhibitor of platelet ____________ production.
thromboxane A2
Thromboxane stimulates platelet _________ and ____________.
aggregation
vasoconstriction
What is the difference between low and higher doses of aspirin?
(2)
- they have similar therapeutic effects.
- higher dose comes with higher risk of bleed.
What type of drug is clopidogrel?
2
- antiplatelet
- prodrug
Clopidogrel and __________ both inhibit ___________ activated platelet aggregation.
ticagrelor
ADP receptor
Which pathway is blocked by blockage of the ADP receptor?
GP2b3a
What is clopidogrel always used in combination with?
aspirin
Patients with low _________ demonstrate resistance to clopidogrel.
CYP 2C19
What type of drug is a low molecular weight heparin?
anticoagulant
Give examples of LMWH’s.
(4)
What is the other class of heparin? Give an example.
Enoxaparin
Dalteparin
Tinzeparin
Fondaparinux
unfractioned heparin (UFH) e.g. warfarin
Which ‘LMWH’ is not technically a LMWH?
fondaparinux - it is synthetic
What is the advantage of fondaparinux over, say, enoxaparin?
2
- less risk of bleed
- less overall harm
- an integrin complex found on platelets receptor for fibrinogen, aids in platelet activation.
- platelet activation by ADP (blocked by __________) leads to a conformational change in platelet _________ receptor that induces binding to fibrinogen.
clopidogrel (antiplatelet)
GPIIb/IIIa
Give example of GP2b3a receptor inhibitors.
What are the contraindications to this drug type?
tirofiban
- minor bleed
- major bleed (less common)
When are beta blockers used when treating ACS/MI?
What are the contraindications to beta blockers?
- acute MI (although limited)
- post MI (secondary prevention)
- unstable angina
- MI following sudden cessation
- bradycardia
- patients at high risk of cardiogenic shock
