What drugs are used in emergency situations?

Emergency Medications: Core Drugs and Clinical Applications

Cardiac Arrest Medications

For adult cardiac arrest, epinephrine or vasopressin may be considered as vasopressors to improve return of spontaneous circulation (ROSC), though neither has been shown to improve survival to hospital discharge or neurological outcomes. 1

Vasopressors in Cardiac Arrest

• Epinephrine remains the primary vasopressor despite lack of evidence for long-term survival benefit, with demonstrated improvement in ROSC for both ventricular fibrillation (VF) and pulseless electrical activity (PEA)/asystole 1
• Vasopressin shows no difference in outcomes (ROSC, survival to discharge, or neurological outcome) when compared with epinephrine as first-line vasopressor 1
• High-dose epinephrine improves ROSC but provides no survival advantage over standard dosing 1
• No placebo-controlled trials demonstrate that routine vasopressor use increases survival to hospital discharge 1

Antiarrhythmic Drugs for Shock-Refractory VF/Pulseless VT

Either amiodarone or lidocaine may be considered for shock-refractory ventricular fibrillation/pulseless ventricular tachycardia (VF/pVT), with both drugs showing similar efficacy based on short-term outcomes only. 1

• Amiodarone dosing: First dose 300 mg IV/IO bolus; second dose 150 mg IV/IO 1
• Lidocaine dosing: First dose 1-1.5 mg/kg IV/IO; second dose 0.5-0.75 mg/kg IV/IO 1
• Amiodarone demonstrated benefit over standard care (including lidocaine) for survival to hospital admission in shock-refractory VF/VF, but not survival to discharge 1
• The 2018 American Heart Association update places amiodarone and lidocaine on equal footing, whereas previous guidelines favored amiodarone as first-line 1
• Critical limitation: No antiarrhythmic drug has been shown to increase long-term survival or survival with good neurological outcome 1

Drugs NOT Recommended in Cardiac Arrest

• Atropine: Insufficient evidence for routine use in cardiac arrest (asystole, PEA, pulseless VT, VF) 1
• Magnesium: Four randomized controlled trials showed no increase in ROSC or survival when compared with placebo for VF 1
• Procainamide, bretylium, buffers, calcium, hormones, fibrinolytics: No convincing evidence that routine use increases survival to hospital discharge 1

Pediatric Emergency Medications

Pediatric emergency drug selection should be guided by the specific clinical scenario, with dosages calculated by weight in mg/kg for most medications and mcg/kg for high-potency drugs. 1

Key Pediatric Considerations

• Intravenous (IV) route is preferred; intraosseous (IO) administration is acceptable when IV access cannot be promptly obtained 1
• Certain drugs (lidocaine, epinephrine, atropine, naloxone—memory aid: LEAN) can be administered endotracheally if no IV access is available 1, 2
• Standardized drip concentrations should replace "rule of 6" calculations to reduce medication errors 1
• Most drugs should be administered over several minutes to avoid transient excessive blood concentrations, with exceptions including adenosine (requires rapid infusion) and phenytoin/fosphenytoin (requires slow infusion) 1

Psychiatric Emergency Medications

For psychiatric emergencies presenting to the emergency department, risperidone is the most commonly used antipsychotic (19.39% of prescriptions), followed by lorazepam (13.60%) and clonazepam (4.28%). 3

Common Psychiatric Emergency Presentations

• Substance abuse (32.72% of cases) and schizophrenia (21.81%) are the most frequent diagnoses requiring emergency psychiatric medication 3
• Approximately 74.5% of emergency physicians prescribe drugs according to standard guidelines for psychiatric emergencies 3

Benzodiazepines in Emergency Settings

• Lorazepam is highly effective for status epilepticus, with 80% of patients responding to 4 mg IV (given as two 2 mg doses) within 10 minutes, maintaining seizure freedom for at least 30 minutes 4
• Diazepam showed 57% response rate in the same study, though this difference may not reflect real-world comparative performance 4
• Both benzodiazepines carry significant risks when combined with opioids, including profound sedation, respiratory depression, coma, and death 4, 5

Hypertensive Emergency Medications

For true hypertensive emergencies (BP >180/120 mmHg with acute end-organ damage), immediate IV therapy with titratable agents such as labetalol, nicardipine, or clevidipine is required in an ICU setting. 6, 7

IV Agents for Hypertensive Emergency

• Labetalol: First-line agent with combined alpha and beta-blocking properties; dose 0.25-0.5 mg/kg IV bolus, followed by 2-4 mg/min continuous infusion, then 5-20 mg/h 7
• Nicardipine: Initial dose 5 mg/h, increasing every 5 minutes by 2.5 mg/h to maximum 15 mg/h 6
• Nitroglycerin: Preferred for acute coronary events and acute cardiogenic pulmonary edema 7
• Sodium nitroprusside: Use with caution due to cyanide toxicity risk 7

Oral Agents for Hypertensive Urgency (No End-Organ Damage)

• Captopril (ACE inhibitor): First-line oral option, but must start at very low doses due to risk of sudden BP drops in volume-depleted patients 6, 7
• Labetalol: Oral option with dual mechanism of action 6, 7
• Extended-release nifedipine: Acceptable option, but short-acting nifedipine should NEVER be used due to risk of stroke and death from uncontrolled BP falls 6, 7

BP Reduction Targets

• Reduce systolic BP by no more than 25% within first hour 6, 7
• If stable, aim for BP <160/100 mmHg over next 2-6 hours 6, 7
• Cautiously normalize BP over following 24-48 hours 7

Critical Routes of Administration

Endotracheal Drug Administration

Epinephrine, atropine, and naloxone are effective when administered endotracheally in emergency situations when IV/IO access is unavailable. 2

• Lidocaine may be considered endotracheally based on anecdotal evidence and chemical properties 2
• Drugs that should NOT be given endotracheally: bretylium, diazepam, calcium salts, isoproterenol, norepinephrine, and sodium bicarbonate 2

Common Pitfalls to Avoid

• Never treat asymptomatic severe hypertension as an emergency—most patients have urgency, not emergency, and aggressive IV treatment can cause harm 6
• Avoid rapid, uncontrolled BP lowering in hypertensive emergencies, as this causes further complications including stroke and death 7
• Do not use short-acting nifedipine for any hypertensive situation due to risk of cardiovascular complications 6, 7
• Recognize that no vasopressor or antiarrhythmic has proven long-term survival benefit in cardiac arrest, despite widespread use 1
• Avoid mixing or diluting diazepam with other solutions or drugs in syringe or infusion container 5
• Be aware of drug-drug interactions that can increase emergency hospitalization risk 2.4-fold, particularly with drugs prolonging QT interval and cytochrome P450 interactions 8