Should a patient with sustained ventricular tachycardia receive both epinephrine (adrenaline) and amiodarone after the third unsuccessful shock?

Yes, administer both epinephrine and amiodarone after the third unsuccessful shock in sustained VT.

For shockable rhythms including sustained VT, current guidelines explicitly recommend giving epinephrine after the third shock, and amiodarone should be administered at this same time point for shock-refractory ventricular arrhythmias 1.

Medication Timing and Sequence

Epinephrine Administration

• Give epinephrine 1 mg IV/IO after the third shock if initial CPR and defibrillation attempts fail 1
• Repeat every 3-5 minutes (operationally, every second CPR cycle after initial dose) 1
• The literature strongly supports prioritizing defibrillation and CPR initially, reserving epinephrine for when these measures prove unsuccessful 1

Amiodarone Administration

• Administer 300 mg IV/IO bolus after the third unsuccessful shock 2, 3
• A second dose of 150 mg may be given for recurrent or breakthrough VF/VT 2, 3
• Mix in 100 mL D5W and infuse over 10 minutes to minimize hypotension 3

Critical Rationale for Combined Therapy

The combination approach is supported by multiple lines of evidence:

Hemodynamic Safety: Animal studies demonstrate that amiodarone administered alone produces significantly lower coronary perfusion pressures during CPR compared to epinephrine alone or the combination 4. When amiodarone is combined with epinephrine, hemodynamic parameters during CPR are similar to epinephrine alone, eliminating concerns about amiodarone's vasodilatory effects 4.

Efficacy Data: While neither epinephrine nor amiodarone has been definitively shown to improve long-term survival or favorable neurological outcomes, both medications improve short-term outcomes 2, 1:

• Amiodarone increases survival to hospital admission compared to lidocaine (22.8% vs 12.0%, p=0.009) 5
• The benefit is most pronounced in witnessed arrests where time to drug administration is shorter 2
• Epinephrine increases ROSC rates, though with mixed effects on neurological outcomes 1

Practical Implementation

Administration Protocol

1. After third unsuccessful shock, immediately give:
   • Epinephrine 1 mg IV/IO push
   • Amiodarone 300 mg IV/IO (diluted in 100 mL D5W over 10 minutes)
2. Continue high-quality CPR during medication administration
3. Attempt fourth defibrillation after medication delivery
4. Repeat epinephrine every 3-5 minutes
5. Consider second amiodarone dose (150 mg) for recurrent VF/VT

Critical Pitfalls to Avoid

• Never delay defibrillation to give medications - the sequence matters 6. Giving epinephrine before defibrillation is associated with worse outcomes (survival 22.4% vs 29.7%, adjusted OR 0.69) 6
• Do not use amiodarone concentrations >2 mg/mL in peripheral veins due to phlebitis risk; use central access for higher concentrations 3
• Avoid excessive doses - mean daily doses above 2100 mg are associated with increased hypotension risk 3
• Monitor for hypotension - if it occurs, slow the amiodarone infusion rate 3

Alternative Consideration

Lidocaine may be substituted for amiodarone (1-1.5 mg/kg first dose, then 0.5-0.75 mg/kg) if amiodarone is unavailable or contraindicated 2. The 2018 guidelines updated recommendations to consider either amiodarone or lidocaine as equivalent options for shock-refractory VF/VT, whereas previous guidelines favored amiodarone 2. However, amiodarone demonstrated superior survival to hospital admission in head-to-head comparison 5.

The evidence consistently supports administering both medications together after the third shock, with the epinephrine providing necessary hemodynamic support while amiodarone addresses the refractory arrhythmia.