ACLS Pharmacology
A small set of drugs appears again and again across the ACLS algorithms. Knowing each drug's dose, route, and indication cold lets you support the team without slowing the code.
Arrest drugs: epinephrine and antiarrhythmics
Epinephrine 1 mg IV/IO every 3 to 5 minutes is used in cardiac arrest; it raises coronary perfusion pressure and improves ROSC and short-term survival. In nonshockable rhythms (asystole/PEA) give it as early as possible; in shockable rhythms (VF/pVT) give it after initial CPR and shocks fail. For VF/pVT that persists after shocks, amiodarone or lidocaine may be considered: in a large prehospital trial each improved survival to hospital admission, with the clearest benefit when given early in witnessed arrests. Use the doses on your current AHA algorithm and your institution's protocol. Antiarrhythmics are layered on top of — never instead of — CPR and defibrillation. Routine calcium, sodium bicarbonate and magnesium did not improve arrest outcomes.
Rate and rhythm drugs: atropine and adenosine
Atropine is first-line for symptomatic bradycardia and has been effective in observational studies; the FDA-approved label gives an initial antivagal dose of 0.5 mg to 1 mg, titrated to heart rate and symptoms, and limits the total to 2 to 3 mg in patients with coronary artery disease. If atropine fails, use transcutaneous pacing or an epinephrine or dopamine infusion. Adenosine is used for stable, regular, narrow-complex tachycardia after vagal maneuvers fail: the label gives 6 mg as a rapid IV bolus, then 12 mg if needed, each followed by a rapid saline flush because adenosine's half-life is very short. Avoid adenosine in asthma, where it can cause severe bronchospasm.
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