What are the first‑line medications for common acute emergencies and the urgent emergency interventions that should be performed simultaneously in the emergency department?

First-Line Emergency Medications and Urgent Interventions in the Emergency Department

The most critical first-line interventions in the ER follow the ABC approach (Airway, Breathing, Circulation) with immediate administration of condition-specific medications: epinephrine 1 mg IV/IO every 3-5 minutes for cardiac arrest, naloxone 0.2-2 mg IV/IM for opioid overdose with respiratory depression, and intramuscular epinephrine 0.3-0.5 mg for anaphylaxis, while simultaneously establishing IV/IO access, providing high-quality CPR when indicated, and securing the airway. 1, 2

Immediate Life-Saving Interventions (Performed Simultaneously)

ABC Assessment and Stabilization

• Assess and secure the airway immediately - this is the highest priority without which resuscitation cannot succeed 3, 4
• Administer 100% oxygen via non-rebreather mask or bag-mask ventilation for all critically ill patients 1, 2
• Intubate the trachea if airway cannot be maintained or patient requires mechanical ventilation 1
• Establish IV/IO access immediately for medication administration 1
• Monitor vital signs continuously including ECG, blood pressure, oxygen saturation, and capillary refill 5

Positioning Based on Clinical Presentation

• Elevate legs (Trendelenburg position) for hypotension to improve venous return 1, 2
• Sit upright for respiratory distress or bronchospasm 2
• Recovery position if unconscious but breathing 2

First-Line Medications by Emergency Condition

Cardiac Arrest

• Epinephrine 1 mg IV/IO every 3-5 minutes is the first-line vasopressor during CPR, providing α-agonist vasoconstriction plus β2-agonist effects that restore cardiac contractility and pacemaker function 1, 6, 7
• High-quality CPR with compressions at least 2 inches deep at 100-120/min, minimizing interruptions 1
• Defibrillation for VF/pVT: biphasic 120-200 Joules (or manufacturer recommendation), monophasic 360 Joules 1
• Amiodarone 300 mg IV/IO bolus (then 150 mg) OR lidocaine 1-1.5 mg/kg IV/IO (then 0.5-0.75 mg/kg) for refractory VF/pVT 1

Critical pitfall: Standard resuscitative measures take absolute priority over any antidote administration - never delay CPR or defibrillation 1

Anaphylaxis

• Intramuscular epinephrine 0.3-0.5 mg (0.3-0.5 mL of 1:1000 solution) into lateral thigh immediately upon suspicion - this is the single most important intervention 1, 2
• Repeat epinephrine every 5-15 minutes if bronchospasm or hypotension persists 1, 2
• IV epinephrine 50 mcg (0.5 mL of 1:10,000 solution) for severe cardiovascular collapse, repeated as needed 1
• Rapid IV crystalloid bolus 1-2 liters (or 5-10 mL/kg) normal saline or lactated Ringer's solution 1, 2
• Secondary medications (only after epinephrine): chlorphenamine 10 mg IV, hydrocortisone 200 mg IV 1
• Salbutamol infusion for persistent bronchospasm unresponsive to epinephrine 1

Critical pitfall: Antihistamines and corticosteroids are NOT first-line - epinephrine must be given first 1, 2

Opioid Overdose with Respiratory Depression

• Naloxone 0.2-2 mg IV/IO/IM titrated to restore respiratory drive and protective airway reflexes, NOT full consciousness 1
• Intranasal naloxone 2-4 mg repeated every 2-3 minutes if IV access unavailable 1
• Bag-mask ventilation or rescue breathing takes priority if naloxone not immediately available 1
• Maintenance infusion: two-thirds of the waking dose per hour to prevent recurrent respiratory depression 1

Critical pitfall: In cardiac arrest from suspected opioid overdose, CPR takes absolute priority over naloxone - naloxone has no proven benefit in cardiac arrest 1

Important consideration: For combined opioid-benzodiazepine overdose, administer naloxone first before considering flumazenil 1

Benzodiazepine Overdose

• Flumazenil 0.2 mg IV titrated up to 1 mg for pure benzodiazepine overdose with respiratory depression 1
• Contraindications to flumazenil (causes harm): chronic benzodiazepine use, seizure disorder, co-ingestion of pro-convulsant drugs (tricyclic antidepressants, cocaine), unknown overdose 1
• Flumazenil has NO role in cardiac arrest from benzodiazepines 1

Critical pitfall: Flumazenil can precipitate refractory seizures and ventricular dysrhythmias in high-risk patients - when in doubt, support with airway management instead 1

Poisoning/Toxicology Emergencies

β-Blocker or Calcium Channel Blocker Overdose:

• Glucagon 2-10 mg IV bolus then 1-15 mg/h infusion (anticipate vomiting) 1
• High-dose insulin 1 U/kg bolus then 1-10 U/kg/h infusion with dextrose supplementation 1
• Calcium chloride 2000 mg IV (20 mL of 10% solution) or calcium gluconate 6000 mg IV, then infusion 1
• Atropine 0.5-1 mg IV every 3-5 minutes for bradycardia 1

Organophosphate Poisoning:

• Atropine 1-2 mg IV doubled every 5 minutes until bronchorrhea and bronchospasm resolve, then 10-20% of loading dose per hour 1
• Pralidoxime 1-2 g IV then 400-600 mg/h infusion 1

Sodium Channel Blocker Toxicity (tricyclic antidepressants, cocaine):

• Sodium bicarbonate 50-150 mEq IV bolus then prepare 150 mEq/L solution infused at 1-3 mL/kg/h 1

Digoxin Toxicity:

• Digoxin immune Fab 10-20 vials IV for acute overdose with critical illness 1

Cyanide Poisoning:

• Hydroxocobalamin 5 g IV 1
• Sodium nitrite 300 mg IV plus sodium thiosulfate 12.5 g IV 1

Local Anesthetic Systemic Toxicity:

• Intravenous lipid emulsion (20%) 1.5 mL/kg bolus then 0.25 mL/kg/min infusion for up to 30 minutes 1

Shock States

• Norepinephrine infusion is the preferred first-line vasopressor for undifferentiated shock requiring pharmacologic blood pressure support 5
• Rapid IV crystalloid 500-1000 mL bolus (minimum 30 mL/kg) before escalating vasopressors 5
• Epinephrine infusion 0.05-0.1 mcg/kg/min if shock persists despite norepinephrine, titrated every 5-15 minutes to MAP ≥65 mmHg 5
• Invasive arterial line monitoring for continuous blood pressure assessment 5

Universal Emergency Interventions

Monitoring Requirements

• Continuous ECG monitoring for all critically ill patients 1, 5
• Pulse oximetry to guide oxygen therapy 2
• Capnography to confirm endotracheal tube placement and monitor CPR quality (ETCO2 ≥40 mmHg suggests ROSC) 1
• Serial lactate measurements to assess tissue perfusion 5

Documentation Essentials

• Exact timing of symptom onset, medication administration, and interventions 1, 2
• All vital signs at presentation and throughout resuscitation 2
• Specific drug names, doses, routes and patient response 2
• Time of emergency activation and transfer decisions 2

Post-Resuscitation Care

• Observe 24 hours after severe reactions or cardiac arrest, ideally in ICU setting 1, 2
• Transfer to hospital with emergency department capabilities even if symptoms improve 2
• Document allergies permanently in medical records for causative agents 2, 8

Critical principle: The ABCDE approach (Airway, Breathing, Circulation, Disability, Exposure) provides the algorithmic framework for all emergency assessments, with team members performing multiple tasks simultaneously rather than sequentially 1, 3