Acute Coronary Syndrome Medications Flashcards
What are the three classes of early hospital therapy for acute coronary syndromes (ACS)?
- Anti-Ischemic Therapy
- Antiplatelet Therapy
- Anticoagulant Therapy
When is oxygen therapy recommended?
Patients with a PaO2 of <90 percent, in respiratory distress, or those with other high risk features for hypoxemia
When is sublingual vs IV nitroglycerin given?
Sublingual - initially, i.e. in the ambulance, up to three tablets
IV - for ongoing ischemia, hypertension, or heart failure in the hospital
What is the mechanism of action of nitroglycerin? Does it affect preload / afterload? Does it work quickly?
Metabolized to NO which increases cGMP grump, dephosphorylating MLCK, inducing smooth muscle relaxation and vasodilation
- > especially affects the venous system -> reduction in preload and systemic vascular resistance (afterload)
- > may also dilate coronary vessels slightly
Works quickly -> a few minutes if taken sublingually
What are the contraindications for nitroglycerin? There are four, three were covered in sketchy, the other is intuitive, but be specific about it.
- Hypotension (SBP < 90 mmHg) -> avoid when this may be possible, as it will worsen this
- Right ventricular infarction -> reduction in preload may cause cardiogenic shock (think of sketchy no right turn sign)
- Aortic stenosis -> Need the preload into the left heart to maintain blood flow -> think of the curled smokestack in sketchy
- Phosphodiesterase inhibitors (PDE5) taken within the last 24 hours -> i.e. sildenafil -> fill = coal truck in sketchy
What are the beta blockers of choice for ACS? How quickly should they be started? What types should be used?
Cardioselective agents: Metoprolol and Atenolol
Should be started within 24 hours
Early: Use short-acting and low dose, titrating upwards for tighter control
Discharge: Give long-acting beta blockers
When should IV beta blockers be used?
When in a hypertensive emergency (SBP > 200) or patients in atrial fibrillation with rapid ventricular response (need to slow conduction at the AV node)
Otherwise, contraindicated for all the reasons on the next card
What are the contraindications for beta-blockers?
- Active bronchospasm - i.e. asthmatics
- Severe bradycardia - will slow further
- Heart block greater than 1st degree (unless have pacemaker)
- Pulmonary edema -> don’t want to slow heart further in HF
- Hypotension
- MI due to cocaine use -> unopposed alpha1 can cause coronary artery vasospasm and extreme HTN
What other drug should be considered if betablockers are contraindicated?
non-DHP calcium channel blockers
When should statin therapy be started? Which is recommended?
At time of diagnosis: atorvastatin or rosuvastatin is recommended (longer half lives)
When are ACE inhibitors recommended in ACS?
For heart failure of EF <40% - will help relieve the fluid overload
Not needed if EF > 40%
What should be given to patients if they are intolerant to an ACE inhibitor?
ARBs - i.e. losartan or valsartan
Why are amlodipine and nefedipime contraindicated in most ACS patients?
Without already being on a beta-blocker, they will cause reflex tachycardia. Also, they don’t really help
When should NSAIDs and COX-2 inhibitors be given in ACS?
I tricked you -> they shouldnt. Only aspirin is okay, otherwise they are contraindicated.
What is the mechanism of action of aspirin, and why is it given at low doses daily on discharge?
IRREVERSIBLY inhibits COX-1 (why it is okay vs other NSAIDs)
Low doses -> blocks TXA2 synthesis by platelets, without having a significant effect on the vasodilator prostacyclin (PGI2)
How should a patient coming in with ACS be treated with aspirin?
An initial loading dose of 2-4 baby aspirins (81mg each) should be given, via chewing an uncoated pill
-> rapid antithrombic effect due to almost complete inhibition of TXA2
When is aspirin contraindicated?
In patients >60 years of age with peptic ulcer bleeding
What receptor do the ADP receptor blockers block? What are the relevant ones’ names?
P2Y12 -> think 2-12 year olds playing baseball
-grel = grilling hot dogs, all of these drugs will have a grel in them
Clopidogrel
Prasugrel
Ticagrelor
What is the recommendation for P2Y12 therapy in ACS?
At least one YEAR of dual antiplatelet therapy with aspirin + P2Y12 receptor blocker in ACS.
What is the dosing of clopidogrel dosing?
300 mg loading dose + 75 mg maintenance dose daily afterward (same as aspirin, 4x normal dose)
Why would prasugrel be used rather than clopidogrel?
- More rapid onset
- Higher degree of inhibition
- Some patients are clopidogrel resistant based on ADP receptor polymorphisms
How does ticagrelor differ from prasugrel? How is it similar?
Differs - binds REVERSIBLY -> clopidogrel and prasugrel are irreversible
Similar - rapid onset, more intense inhibition, same contraindications
When are prasugrel / ticagrelor contraindicated?
Prior TIA or stroke
>75 years of age (elderly)
When are GP IIb/IIIa inhibitors used? Which one is recommended?
Used for patients undergoing early cardiac catheterization to prevent thrombus formation
Eptifibatide - think TIED score in sketchy
Preferred over abciximab or TIrofiban - “tie”
What are the anticoagulant therapies of choice for early hospital care in ACS?
- Unfractionated heparin
- Enoxaparin (think of the pair of foxes held by fido for fondaparinux or enoxaparin)
- > inhibit the factor Xa fox
What is the mechanism of action of bivalirudin?
Think of the gator about to eat the beaver, with the sign no intRUDIN
Argatroban and dibigatran are direct thrombin (beaver) inhibitors, bivalirudin is also a direct thrombin inhibitor
When are ACE inhibitors or ARBs recommended for secondary prevention? What numbers do you have to pay attention to?
CHF, EF < 40% (like in ACS), but also hypertension and DM (good for nephropathy)
Make sure the patient K+ is <5.0 mEq/L and Creatinine Clearance is >30 mL/min if giving with spironolactone
What is the typical secondary prevention therapy for ACS?
- Dual therapy for 1 year: aspirin / P2Y12
- Beta blockers
- Ace inhibitor / ARB - if indicated
- Statin
- Standard risk factor management
When should anticoagulants like heparin and enoxaparin be considered?
Only in thrombus related NSTEMI -> not indicated for STEMI
