Drug reasoning during cardiac arrest and peri-arrest instability: know which medications can help, which are merely optional, and which routine drugs distract from high-quality CPR, defibrillation and treatment of reversible causes.
Keep high-quality CPR and defibrillation ahead of medication administration in shockable arrest.
Use epinephrine at the appropriate point without implying that vasopressors replace definitive arrest care.
Use amiodarone or lidocaine selectively for shock-refractory VF/pVT.
AHA 2025: routine calcium is not recommended, routine bicarbonate is not recommended, and routine magnesium is not recommended during undifferentiated adult cardiac arrest.
Choose procainamide/adenosine only in the stable wide-complex tachycardia phenotypes where they fit.
Full arrest and post-ROSC critical-care pathway.
Mechanism-specific poisoning pharmacology.
The table below is a selection framework. Open the individual monograph for exact dosing, preparation, renal/CRRT/IHD adjustment, interactions and evidence traceability.
ICU role: Core vasopressor in adult cardiac arrest and infusion/bolus therapy in selected peri-arrest states.
Monitor: Rhythm, ROSC, BP after ROSC and perfusion.
ICU role: Antiarrhythmic option for VF/pVT unresponsive to defibrillation and selected stable ventricular arrhythmias.
Monitor: ECG, BP, QT and hepatic effects with ongoing therapy.
ICU role: Alternative antiarrhythmic to amiodarone for shock-refractory VF/pVT and selected ventricular arrhythmias.
Monitor: ECG, neurologic status and hepatic perfusion.
ICU role: Slow-infusion class IA agent for selected stable wide-complex tachycardia.
Monitor: Continuous ECG/BP, QRS/QT and renal function.
ICU role: Ultra-short AV nodal blocker for regular narrow SVT and selected stable regular monomorphic WCT diagnosis/therapy.
Monitor: Continuous ECG and resuscitation readiness.
ICU role: First-line medication for symptomatic bradycardia in appropriate adult peri-arrest algorithms.
Monitor: HR, BP, rhythm and perfusion.
ICU role: Treatment for torsades/long-QT polymorphic VT and selected electrolyte-driven arrhythmias.
Monitor: Rhythm, Mg/K, BP and renal function.
ICU role: Membrane stabilization for hyperkalemia and selected calcium-channel blocker/toxicologic indications.
Monitor: ECG, ionized calcium and underlying cause.
ICU role: Targeted therapy for sodium-channel blockade, severe hyperkalemia/acidemia contexts and selected poisonings.
Monitor: ABG/VBG, sodium, potassium, ECG/QRS and ventilation.
| Agent | ICU role | Why I choose it | Why I hesitate | What I monitor |
|---|---|---|---|---|
| Epinephrine Potent Alpha-1, Beta-1, and Beta-2 Adrenergic Agonist | Core vasopressor in adult cardiac arrest and infusion/bolus therapy in selected peri-arrest states. | ✓ Use according to arrest rhythm/timing while uninterrupted CPR/defibrillation continue. | ✕ More epinephrine is not a substitute for correcting hypoxia, tamponade, tension PTX, thrombosis or other reversible causes. | Rhythm, ROSC, BP after ROSC and perfusion. |
| Amiodarone Class III Antiarrhythmic (Multi-Channel Blocker) | Antiarrhythmic option for VF/pVT unresponsive to defibrillation and selected stable ventricular arrhythmias. | ✓ Shock-refractory VF/pVT after defibrillation strategy; selected VT/electrical storm with specialist strategy. | ✕ Not a treatment for PEA/asystole and not first-line for classic torsades. | ECG, BP, QT and hepatic effects with ongoing therapy. |
| Lidocaine IV Class Ib antiarrhythmic | Alternative antiarrhythmic to amiodarone for shock-refractory VF/pVT and selected ventricular arrhythmias. | ✓ Reasonable alternative when amiodarone is unavailable/undesirable. | ✕ CNS toxicity accumulates with high exposure, hepatic dysfunction and low-flow states. | ECG, neurologic status and hepatic perfusion. |
| Procainamide Class IA Sodium-Channel Blocking Antiarrhythmic | Slow-infusion class IA agent for selected stable wide-complex tachycardia. | ✓ Stable regular monomorphic WCT when QT is not prolonged and significant HF/hypotension are absent. | ✕ Not a rapid arrest drug; stop for hypotension or major QRS widening. | Continuous ECG/BP, QRS/QT and renal function. |
| Adenosine Endogenous Purine Nucleoside / AV Nodal Blocking Agent | Ultra-short AV nodal blocker for regular narrow SVT and selected stable regular monomorphic WCT diagnosis/therapy. | ✓ When an AV-node-dependent rhythm is likely and the rhythm is regular. | ✕ Do not give for unstable, irregularly irregular or polymorphic WCT. | Continuous ECG and resuscitation readiness. |
| Atropine Anticholinergic / Competitive Muscarinic Receptor Antagonist | First-line medication for symptomatic bradycardia in appropriate adult peri-arrest algorithms. | ✓ Symptomatic bradycardia while preparing pacing/infusion strategies if ineffective. | ✕ Do not delay transcutaneous pacing/epinephrine/dopamine when atropine fails or high-grade block is unlikely to respond. | HR, BP, rhythm and perfusion. |
| Magnesium Sulfate Electrolyte / Multi-Mechanism Membrane & Neuromuscular Modulator | Treatment for torsades/long-QT polymorphic VT and selected electrolyte-driven arrhythmias. | ✓ Torsades or documented severe hypomagnesemia. | ✕ Routine magnesium in undifferentiated cardiac arrest is not recommended. | Rhythm, Mg/K, BP and renal function. |
| Calcium Gluconate Electrolyte / Cardiac Membrane Stabilizer | Membrane stabilization for hyperkalemia and selected calcium-channel blocker/toxicologic indications. | ✓ Hyperkalemic ECG toxicity or disease-specific indication. | ✕ Routine calcium in undifferentiated cardiac arrest is not recommended. | ECG, ionized calcium and underlying cause. |
| Sodium Bicarbonate Alkalinizing Agent / Buffer | Targeted therapy for sodium-channel blockade, severe hyperkalemia/acidemia contexts and selected poisonings. | ✓ Mechanism-specific indications such as TCA/sodium-channel toxicity. | ✕ Routine bicarbonate in undifferentiated cardiac arrest is not recommended. | ABG/VBG, sodium, potassium, ECG/QRS and ventilation. |
Why: AHA 2025 supports amiodarone or lidocaine as optional antiarrhythmics but advises against routine calcium/bicarbonate/magnesium.
Why: Calcium is appropriate for a specific hyperkalemic arrest mechanism even though routine use in undifferentiated arrest is not recommended.
Why: Mechanism and stability determine the safe drug choices.
Why: Classic torsades is a repolarization problem, not generic monomorphic VT.
Recognition becomes selection, then organ-failure adjustment, competing physiology and senior-level prioritization.
PEA arrest after severe hypoxemia; no shockable rhythm.
High-quality CPR, epinephrine according to ALS algorithm, airway/oxygenation and aggressive treatment of the reversible cause. Amiodarone is not indicated for PEA.
VF persists after multiple shocks and CPR cycles.
Continue defibrillation/CPR and epinephrine; amiodarone or lidocaine may be considered for refractory VF/pVT.
ESRD patient arrests after peaked T waves widened into a sine-wave pattern.
Treat the mechanism: IV calcium for membrane stabilization plus insulin/glucose and definitive potassium removal while ACLS continues.
Regular wide tachycardia but baseline QT is markedly prolonged and patient has severe HF.
Procainamide is a poor choice because both prolonged QT and HF increase risk; use an alternative/electrical strategy guided by rhythm mechanism and stability.
Wide QRS, hypotension and ventricular arrhythmia after tricyclic overdose progressing to arrest.
Standard ALS plus aggressive sodium bicarbonate therapy and ventilation/acid-base control for sodium-channel blockade; mechanism-specific treatment is crucial.
Potent direct alpha/beta agonist for anaphylactic shock, cardiac arrest, post-cardiac arrest shock, and refractory septic shock — powerful inotrope and bronchodilator with transient hyperlactatemia.
Broad-spectrum antiarrhythmic used for shock-refractory cardiac arrest, stable ventricular arrhythmias, and rate/rhythm-related management of atrial fibrillation — notable for an extremely long half-life and cumulative multi-orga…
IV sodium-channel blocker used for refractory ventricular arrhythmias and as an alternative to amiodarone in shock-refractory VF/pVT.
IV class IA antiarrhythmic that may be considered for stable monomorphic wide-complex tachycardia. It slows conduction and prolongs repolarization, so hypotension, QRS widening and QT prolongation limit use.
Ultra-short-acting agent that transiently blocks AV nodal conduction to terminate AV-node-dependent reentrant SVT — its sub-10-second half-life makes the rapid-push-plus-immediate-flush administration technique as important as th…
Competitive muscarinic antagonist that blocks vagal parasympathetic tone at the SA and AV nodes, used as first-line for acute symptomatic sinus bradycardia (1 mg IV push q3–5m, max 3 mg) and in megadoses for organophosphate/choli…
Spans four genuinely distinct ICU indications — torsades de pointes, adjunctive severe asthma therapy, eclampsia/severe preeclampsia, and simple hypomagnesemia repletion — each with its own mechanism-relevant dosing; no single do…
First-line cardiac membrane stabilizer for hyperkalemic ECG changes and definitive replacement therapy for symptomatic hypocalcemia — the single most important teaching point is that it stabilizes the myocardium without changing …
A deliberately narrow-role buffer reserved for severe metabolic acidosis with concurrent AKI, sodium-channel-blocker toxicity, and select hyperkalemia with significant concurrent acidemia — explicitly NOT a routine therapy for la…
This Masterclass teaches selection and reasoning. Exact dosing, concentration, infusion preparation, renal/hepatic/RRT adjustment and monitoring must be checked in the linked medication monograph and the institution's current formulary/protocol. Local resistance patterns and regulatory drug availability can change faster than a static teaching page.