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Oral Medications to reduce Infarction size and improve mortality.
The American Heart Association and American College of Cardiology (AHA/ACC) guidelines for
acute myocardial infarction and unstable angina list four oral medications as having Class I indications for
reduction in mortality and morbidity in the setting of ACS. In the ACC/AHA guidelines, Aspirin, nitrates
and beta blockers recommended for all patients with ACS (MI and unstable angina) and are to be given
immediately based on clinical history, even if initial EKG is normal Clopidogrel (Plavix) is
recommended for all patients with ACS (non-ST MI elevated MI or unstable angina) who are not
candidates for early angiography. In the Wilderness setting once the diagnosis of ACS is suspected, the
patient should be treated aggressively with these four oral medications. The studies supporting these
conclusions are:
·
ISIS-2 Trial: ASPIRIN treatment reduced mortality by 23% in acute MI in pre-thrombolytic
era.(platelet cycloxygenase inhibitor)
·
Meta analysis of pre- thrombolytic era nitrate trials: NITROGLYCERIN treatment resulted in a
35% reduction in mortality from acute MI.(vasodilator)
·
ISIS-I and MIAMI trials: BETABLOCKER therapy resulted in 14% and 13% reduction in
mortality with either atenolol or metoprolol in the pre-thrombolytic era. (Reduces heart rate, Blood
Pressure, ischemia and raises Ventricular fibrillation threshold and reduces likelihood of malignant
ventricular arrhythmias and sudden death).
·
CURE Trial: Clopidrogrel therapy resulted in an 18% reduction in MI, death or Stroke in patients
with ACS and non- ST elevated MI treated medically. (platelet ADP-receptor inhibitor)
II. ORAL MEDICATION PROTOCOL FOR PATIENTS WITH SUSPECTED ACUTE MYOCARDIAL
INFARCTION OR UNSTABLE ANGINA PECTORIS (Category 1B recommendation):
·
Aspirin 81mg chewable: 4 tablets immediately then one a day thereafter.
·
Nitroglycerin .4mg tablets: dissolve sublingually every 10 minutes, but do not give if BP
below 100mmHg systolic. If no BP cuff available, administer if pulse palpable in standing
position and there are no signs of hypotension. Do not give if pulse below 60/min. Do not
repeat if syncope develops after initial doses.
·
Clopidogrel 300mg.(oral loading dose) immediately then 75mg a day. (Obese Patients may
require 600 mg loading dose for complete platelet inhibition.)
·
Beta blockers: metoprolol or atenolol 25mg every six hours, beginning 30 minutes after
the onset of chest pain and repeated every six hours even if pain improves. Wait 30
minutes after onset of pain to identify patients with severe shock, bradycardia or acute
pulmonary edema. Do not give if Heart rate below 60/min or BP below 100mmHg systolic
or patient complains of severe shortness of breath or wheezing.
III. ADJUNCTIVE THERAPY FOR ACS PATIENTS IN THE WILDERNESS SETTING
