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)
