Emergency Drugs — Essentials
A comprehensive clinical reference synthesising AHA 2025, ILCOR 2025, Surviving Sepsis Campaign, and CuratED EMPHARM-NET evidence across all major emergency categories.
| Emergency | First-Line Drug(s) | Critical Dose | Guideline |
|---|---|---|---|
| Septic Shock | Norepinephrine | 0.01–0.1 μg/kg/min IV; titrate | SSC 2021 / AJEM 2025 |
| Cardiac Arrest (VF/pVT) | Epinephrine + Amiodarone | Epi 1 mg q3–5 min; Amio 300 mg IV | AHA 2025 / ILCOR 2025 |
| Anaphylaxis | Epinephrine 1:1000 IM | 0.3–0.5 mg IM anterolateral thigh | AHA 2025 Special Circ |
| Status Epilepticus | Lorazepam IV → Levetiracetam | 0.1 mg/kg IV; then 60 mg/kg IV | Neurocritical Care / ESETT |
| AF with RVR | Metoprolol ± Magnesium | Metoprolol 2.5–5 mg IV; MgSO₄ 2 g | AF Guidelines 2024 |
| Hypertensive Emergency | Labetalol or Nicardipine IV | Labetalol 20 mg IV; titrate | ACC/AHA HTN Guidelines |
| Opioid Overdose | Naloxone | 0.4–2 mg IV/IM/IN; repeat q2–3 min | AHA 2024 First Aid; ACMT |
| TCA Toxicity | Sodium Bicarbonate | 1–2 mEq/kg IV; target pH 7.45–7.55 | AHA 2023/2025 Toxicology |
| Digoxin Toxicity | Digoxin-specific Fab | Weight/level-based dosing | AHA 2025 (Class I) |
| Cyanide Poisoning | Hydroxocobalamin | 5 g IV over 15 min | AHA 2025 (Class I) |
| Acute Pulmonary Edema | GTN + Furosemide | GTN 0.4 mg SL; Furosemide 40–80 mg IV | ESC Heart Failure Guidelines |
| Trauma Haemorrhage | Tranexamic Acid (TXA) | 1 g IV over 10 min (within 3 hrs) | CRASH-2 Trial |
| CCB Overdose | Calcium + High-dose Insulin + Lipid | CaCl 1–3 g; Insulin 1 U/kg/hr | AHA 2025 Toxicology |
| Massive PE | Alteplase (tPA) | 100 mg IV over 2 hrs | ESC/AHA PE Guidelines |
| Drug | Dose & Route | Mechanism | Clinical Role | Key Evidence |
|---|---|---|---|---|
| Norepinephrine | 0.01–3 μg/kg/min IV | α1 >> β1 agonist | First-line vasopressor; peripheral admin ≥20G safe | SSC 2021; AJEM 2025 |
| Vasopressin | 0.03 units/min IV | V1 receptor agonist (vasoconstriction) | Add-on when NE >0.25 μg/kg/min; catecholamine-sparing | VASST trial; OVISS/JAMA 2025 |
| Epinephrine | 0.01–0.5 μg/kg/min IV | α1, α2, β1, β2 agonist | Third-line or adjunct for refractory shock | SSC 2021 |
| Angiotensin II | 20 ng/kg/min IV; titrate | AT1 receptor agonist | Refractory vasodilatory shock | ATHOS-3 RCT (NEJM) |
| Dopamine | 5–20 μg/kg/min IV | D1, β1, α1 (dose-dependent) | ⚠ Avoid in septic shock — higher arrhythmia risk | De Backer NEJM 2010 |
Indication: Septic shock refractory to vasopressors (norepinephrine ≥0.25 μg/kg/min for ≥4–6 hours).
Regimen: Hydrocortisone 200 mg/day IV (continuous infusion or 50 mg q6h) plus Fludrocortisone 50 μg/day via nasogastric tube. Evidence: APROCCHSS trial — improved 90-day survival.
Initiate broad-spectrum antibiotics within 1 hour of recognising septic shock (within 3 hours for sepsis without shock). Each hour of delay significantly increases mortality.
For nosocomial or immunosuppressed: anti-pseudomonal coverage (piperacillin-tazobactam or cefepime) + MRSA coverage (vancomycin). Source control is paramount.
The OVISS reinforcement learning study (JAMA 2025) derived and validated optimal timing rules for vasopressin addition to norepinephrine. Peripheral administration of vasopressors through a ≥20-gauge IV line is now confirmed safe, allowing earlier initiation without waiting for central access (AJEM 2025).
The CLOVERS trial (NEJM 2023) showed no mortality difference between restrictive (early vasopressors) and liberal (30 mL/kg crystalloid) fluid strategies — early vasopressors are equally valid when fluids alone fail to restore MAP.
| Drug | Indication | Dose | Route | 2025 Update |
|---|---|---|---|---|
| Epinephrine (Adrenaline) | VF, pVT, PEA, Asystole | 1 mg every 3–5 min | IV / IO | Standard dose preferred; early admin for non-shockable rhythms; no high-dose benefit |
| Amiodarone | Shock-refractory VF/pVT | 300 mg IV bolus, then 150 mg | IV / IO | Preferred first antiarrhythmic for shock-refractory VF |
| Lidocaine | Shock-refractory VF/pVT | 1–1.5 mg/kg IV bolus | IV / IO | Alternative to amiodarone; similar outcomes (ALPS trial) |
| Magnesium Sulfate | Torsades de pointes (TdP) | 1–2 g IV over 5–20 min | IV / IO | ⚠ NOT for routine VF — reserve for TdP only |
| Adenosine | Stable SVT | 6 mg IV rapid, then 12 mg | IV rapid push | First-line for regular narrow-complex SVT |
| Sodium Bicarbonate | Hyperkalemia, TCA OD, metabolic acidosis | 1 mEq/kg IV | IV | ⚠ NOT for routine cardiac arrest use |
| Calcium (CaCl / Gluconate) | Hyperkalemia, CCB toxicity | 500–1000 mg IV slow | IV | Key antidote for calcium channel blocker OD |
| Atropine | Symptomatic bradycardia | 0.5–1 mg IV q3–5 min (max 3 mg) | IV | ⚠ Not used in PEA / Asystole in ALS protocols |
Vasopressin no longer recommended as a substitute for epinephrine in cardiac arrest (updated 2023). Intraosseous (IO) access is now an earlier option when IV fails — not a last resort. Double sequential external defibrillation may be considered for shock-refractory VF (DOSE VF trial). ECMO-CPR is indicated in select etiologies including poisoning-related cardiac arrest.
| Drug | Dose | Route | Mechanism / Role |
|---|---|---|---|
| Epinephrine 1:1000 | 0.3–0.5 mg adult; 0.01 mg/kg child | IM — anterolateral thigh (preferred) | FIRST-LINE. α1: vasoconstriction ↑BP; β1: ↑HR ↑CO; β2: bronchodilation; inhibits mast cell degranulation |
| Epinephrine 1:10,000 | 0.1 mg/kg slow IV | IV / IO (cardiac arrest only) | For anaphylactic cardiac arrest. AHA 2025: higher IM dose (5 mg) under investigation |
| Diphenhydramine (H1) | 25–50 mg | IV / IM / oral | H1 blocker — relieves urticaria/pruritus. ⚠ NOT life-saving — adjunct only |
| Ranitidine / Famotidine (H2) | 50 mg / 20 mg IV | IV | H2 blocker — adjunct for cutaneous features |
| Hydrocortisone / Methylprednisolone | 200 mg IV / 1 mg/kg IV | IV | Prevents biphasic anaphylaxis; delayed onset |
| Salbutamol (Albuterol) | 2.5–5 mg nebulised | Inhaled | β2 agonist — for bronchospasm not responding to epinephrine |
| Glucagon | 1–2 mg IV over 5 min | IV | β-blocker–refractory anaphylaxis; bypasses β-receptor blockade |
For cardiac arrest due to anaphylaxis, standard ACLS protocols apply. The 2025 AHA Special Circumstances Guidelines raise the question of whether a higher-dose IM epinephrine (5 mg) may confer additional benefit in anaphylactic arrest — active investigation. ECMO should be considered for refractory anaphylactic arrest.
| Stage | Drug | Dose & Route | Timing | Evidence |
|---|---|---|---|---|
| First-line (0–5 min) | Lorazepam IV | 0.1 mg/kg IV (max 4 mg) | Immediately | Class I; best evidence |
| First-line (no IV) | Midazolam IM | 10 mg IM (>40 kg adult) | Immediately | RAMPART trial; non-inferior to lorazepam IV |
| First-line (no IV) | Diazepam PR | 0.2 mg/kg rectally | Immediately | Prehospital use |
| Second-line (5–20 min) | Levetiracetam IV | 60 mg/kg IV (max 4500 mg) over 10 min | After BZD failure | ESETT: non-inferior to valproate; fewer ADRs |
| Second-line | Valproate IV | 40 mg/kg IV over 10 min (max 3000 mg) | After BZD failure | ESETT trial (NEJM 2019) |
| Second-line | Fosphenytoin IV | 20 mg PE/kg IV ≤150 mg PE/min | After BZD failure | ESETT trial; CV monitoring required |
| Third-line (RSE) | Propofol | 1–2 mg/kg IV bolus; 20–200 μg/kg/min | ICU setting | Continuous EEG monitoring required |
| Third-line (RSE) | Midazolam infusion | 0.2 mg/kg bolus; 0.05–2 mg/kg/hr | ICU setting | Monitoring essential |
| Third-line (RSE) | Ketamine | 1.5–4.5 mg/kg IV bolus; 1.2–7.5 mg/kg/hr | Emerging use | NMDA antagonist; growing evidence |
Neurocritical Care Society 2024: For moderate-to-severe TBI with acute radiographic abnormalities, routine prophylactic anti-seizure medication may or may not be initiated — evidence shows no significant reduction in long-term epilepsy development. If prophylaxis is used, prefer Levetiracetam or Phenytoin/Fosphenytoin, limited to the first 7 days post-injury.
| Drug Class | Agent(s) | Dose | Indication | Notes |
|---|---|---|---|---|
| Antiplatelet | Aspirin | 300 mg oral loading | All ACS | Immediate, before reperfusion |
| P2Y12 Inhibitor | Ticagrelor | 180 mg loading; 90 mg BD | NSTEMI / STEMI | Preferred over clopidogrel; PLATO trial |
| P2Y12 Inhibitor | Prasugrel | 60 mg loading; 10 mg OD | STEMI (PCI) | Avoid: prior stroke/TIA, age >75, wt <60 kg |
| P2Y12 Inhibitor | Clopidogrel | 300–600 mg loading | ACS (alternative) | When ticagrelor/prasugrel unavailable; more drug interactions |
| Anticoagulant | Enoxaparin | 1 mg/kg SC BD | NSTEMI/STEMI (non-PCI) | Fondaparinux for NSTEMI if no PCI planned |
| Anticoagulant | UFH | 60–70 units/kg IV bolus (max 5000 U) | STEMI (primary PCI) | Weight-based; activated clotting time monitoring |
| Nitrate | GTN (Nitroglycerin) | 0.4 mg SL q5 min × 3; infusion prn | Angina, acute pulmonary oedema | ⚠ Avoid if RV infarction; SBP <90; PDE5 use |
| Beta-blocker | Metoprolol | 25–50 mg oral or 5 mg IV × 3 | Rate control; anti-ischaemic | Avoid in acute decompensated HF, severe bradycardia |
| Drug | Dose | Notes |
|---|---|---|
| Metoprolol IV | 2.5–5 mg IV over 2 min; max 3 doses | First-line rate control; avoid in decompensated HF |
| Diltiazem IV | 0.25 mg/kg IV over 2 min; infusion 5–15 mg/hr | Effective rate control; avoid in pre-excitation AF |
| Digoxin IV | 0.25–0.5 mg IV loading | Slower onset; useful when beta-blockers contraindicated |
| Amiodarone IV | 150 mg IV over 10 min, then infusion | Rate/rhythm control; useful in haemodynamically unstable |
| Magnesium Sulfate | 2 g IV over 15 min (adjunct) | New 2024 update: adjunct to standard rate control of AF-RVR (COR 2a, LOE A) |
| Electrical Cardioversion | 120–200 J biphasic synchronized | If haemodynamically unstable or refractory to drugs |
The 2024 AF Guidelines (CuratED EMPHARM-NET, Am J Emerg Med 2025) recommend that IV magnesium sulfate as an adjunct to standard rate-control agents is reasonable to achieve and maintain rate control (Class 2a, Level of Evidence A). A meta-analysis supports its use; no specific dose was mandated.
| Drug | Dose / Route | Best Indication | Target / Notes |
|---|---|---|---|
| Labetalol IV | 20 mg IV bolus; infusion 0.5–2 mg/min | Most hypertensive emergencies; aortic dissection | 10–20% BP reduction in first hour |
| Nicardipine IV | 5–15 mg/hr infusion, titrated | Hypertensive encephalopathy; post-stroke; eclampsia | 10–15% reduction in first hour |
| Sodium Nitroprusside IV | 0.25–10 μg/kg/min infusion | Acute LVF; aortic dissection (with beta-blocker) | Rapid; careful titration; ⚠ cyanide risk if prolonged |
| GTN (Nitroglycerin) IV | 5–200 μg/min infusion | ACS + hypertension; acute pulmonary oedema | Venous > arterial dilator at low doses |
| Hydralazine IV | 10–20 mg slow IV | Eclampsia / hypertension in pregnancy | Avoid in aortic dissection |
| Magnesium Sulfate IV | 4–6 g loading; 1–2 g/hr maintenance | Eclampsia (seizure prevention + BP) | Gold standard for pre-eclampsia/eclampsia |
| Esmolol IV | 500 μg/kg bolus; 50–300 μg/kg/min infusion | Aortic dissection; peri-operative hypertension | Rapid onset and offset; ideal for fine titration |
| Phentolamine IV | 2–5 mg IV bolus | Catecholamine excess (phaeochromocytoma, MAOI, cocaine) | Alpha-blocker; short-acting |
| Poison / Toxidrome | Antidote / Drug | Dose | Mechanism / Notes |
|---|---|---|---|
| Opioid overdose | Naloxone | 0.4–2 mg IV/IM/IN; repeat q2–3 min prn | μ-opioid antagonist; titrate to adequate respiration (not full reversal) |
| Opioid OD (alternative) | Nalmefene | 0.5 mg/70 kg IV | Longer-acting; ⚠ risk of prolonged withdrawal; major toxicology orgs caution against routine use (CuratED 2024) |
| Benzodiazepine OD | Flumazenil | 0.2 mg IV; repeat up to 1 mg | GABA-A antagonist; ⚠ limited use — risk of seizures in chronic BZD users |
| Beta-blocker OD | Glucagon + High-dose Insulin | Glucagon 3–10 mg IV; Insulin 1 unit/kg/hr | Glucagon bypasses β-receptor; insulin improves myocardial glucose use |
| Calcium channel blocker OD | Calcium + High-dose Insulin + Lipid emulsion | CaCl 1–3 g IV; Insulin 1 unit/kg/hr; Lipid 1.5 mL/kg bolus | Lipid emulsion traps lipophilic drugs; ECMO if refractory |
| Digoxin / cardiac glycoside | Digoxin-specific Fab (DigiFab) | Based on serum level or tablets ingested | Antibody fragments; Class I recommendation (AHA 2025) |
| Organophosphate / Carbamate | Atropine + Pralidoxime (2-PAM) | Atropine 2–4 mg IV (double q5 min until secretions dry); 2-PAM 1–2 g IV over 15–30 min | Atropine blocks muscarinic effects; 2-PAM regenerates cholinesterase (give early) |
| TCA overdose | Sodium Bicarbonate | 1–2 mEq/kg IV; target arterial pH 7.45–7.55 | Reverses sodium channel blockade; Class I recommendation (AHA) |
| Cyanide poisoning | Hydroxocobalamin | 5 g IV over 15 min | Combines with cyanide → cyanocobalamin; Class I (AHA 2025) |
| Methemoglobinaemia | Methylene blue | 1–2 mg/kg IV over 5 min | Electron donor; reduces met-Hb back to Hb; Class I (AHA 2025) |
| Local anaesthetic toxicity (LAST) | 20% Lipid emulsion | 1.5 mL/kg IV bolus; 0.25 mL/kg/min | Lipid sink mechanism; Class 1 for LAST (AHA 2025) |
| Warfarin OD / bleeding | Vitamin K + 4-factor PCC | Vit K 5–10 mg IV; 4F-PCC 25–50 units/kg | PCC for immediate reversal; Vit K for sustained effect |
| Dabigatran reversal | Idarucizumab | 5 g IV (2 × 2.5 g) | Humanised antibody fragment; complete and immediate reversal |
| Anti-Xa reversal (rivaroxaban, apixaban) | Andexanet alfa | 400–800 mg IV bolus + infusion | Recombinant Xa decoy; specific reversal agent |
The push for nalmefene over naloxone is largely driven by manufacturer-sponsored data. Major toxicology organisations — including the American College of Medical Toxicology — caution against routine use of long-acting reversal agents due to prolonged withdrawal risk. Naloxone remains the standard of care (CuratED 2024).
ECMO for toxicologic cardiac arrest (CCB, β-blocker, TCA) is now a class recommendation in the AHA 2025 Special Circumstances Guidelines.
| Emergency | Drug(s) | Dose | Notes |
|---|---|---|---|
| Cardiogenic Pulm Oedema | GTN (Nitroglycerin) | 0.4 mg SL; IV 10–200 μg/min | Reduces preload and afterload; first-line if not hypotensive |
| Cardiogenic Pulm Oedema | Furosemide IV | 40–80 mg IV (1–2 mg/kg) | Venodilation + diuresis; caution in cardiorenal syndrome |
| Cardiogenic Pulm Oedema | Morphine | 2–4 mg IV (controversial) | Venodilation + anxiolysis; ⚠ newer evidence questions routine use |
| Acute Asthma / Bronchospasm | Salbutamol (Albuterol) | 2.5 mg neb q20 min × 3; or MDI 4–8 puffs | Short-acting β2 agonist; first-line bronchodilator |
| Acute Asthma | Ipratropium bromide | 0.5 mg neb q20 min × 3 (with salbutamol) | Anticholinergic; adds to bronchodilation in severe asthma |
| Acute Asthma | Magnesium Sulfate IV | 2 g IV over 20 min | Bronchodilation via Ca²⁺ channel antagonism; for severe/refractory asthma |
| Acute Asthma | Corticosteroids | Hydrocortisone 200 mg IV or Prednisolone 40–50 mg oral | Reduces airway inflammation; early use critical |
| COPD Exacerbation | Salbutamol + Ipratropium | As above (combined neb) | Combined nebulisation preferred in acute COPD |
| Massive PE | Alteplase (tPA) | 100 mg IV over 2 hr (systemic) or catheter-directed | Systemic thrombolysis for massive PE with haemodynamic instability |
| Submassive PE / All PE | UFH | 80 units/kg bolus; 18 units/kg/hr infusion | IV UFH preferred in massive PE before/after thrombolysis |
| Drug / Intervention | Indication | Dose | Key Evidence / Update |
|---|---|---|---|
| Tranexamic Acid (TXA) | Major haemorrhage within 3 hrs of injury | 1 g IV over 10 min, then 1 g over 8 hrs | CRASH-2 trial; reduces haemorrhagic death; ⚠ not recommended after 3 hrs |
| Isotonic Crystalloids | Prehospital trauma resuscitation | Titrated to permissive hypotension (SBP 80–90 mmHg) | NAEMSP 2024: isotonic crystalloids preferred prehospitally |
| Packed RBCs + FFP + Platelets | Haemorrhagic shock | 1:1:1 ratio (balanced resuscitation) | Damage-control resuscitation approach |
| Norepinephrine | Vasodilatory shock in trauma | 0.01–3 μg/kg/min | Peripheral administration acceptable (NAEMSP 2024) |
| Ketamine (RSI) | Rapid sequence intubation in trauma | 1.5–2 mg/kg IV | Haemodynamically safe; analgesic; bronchodilator |
| Succinylcholine (RSI) | Neuromuscular blockade | 1.5 mg/kg IV | Rapid onset/offset; ⚠ caution in hyperkalemia, crush injury >24 hrs |
| Rocuronium (RSI) | If succinylcholine contraindicated | 1.2 mg/kg IV | Reversed by sugammadex 16 mg/kg |
| Levetiracetam / Phenytoin | Seizure prophylaxis in moderate-severe TBI | Lev 500–1000 mg BD or Phenytoin | Neurocritical Care 2024: limit to 7 days; no long-term epilepsy reduction |
NAEMSP 2024 position statement reflects evolving shift toward damage-control resuscitation and permissive hypotension (SBP 80–90 mmHg) in trauma. Isotonic crystalloids are preferred prehospitally; early vasopressor use (norepinephrine) is acceptable via peripheral access. Avoid over-resuscitation with crystalloids — dilutional coagulopathy worsens outcomes.
| Situation | Drug(s) | Key Point |
|---|---|---|
| Eclampsia / Pre-eclampsia | MgSO₄ + Labetalol / Nicardipine | MgSO₄ 4–6 g loading; maintain uterine blood flow; MgSO₄ prevents eclamptic seizures — gold standard |
| Maternal cardiac arrest | Standard ACLS drugs + perimortem C-section | Epinephrine dosing unchanged; consider early delivery within 5 min of arrest if no ROSC |
| Paediatric cardiac arrest | Epinephrine | 0.01 mg/kg IV/IO (max 1 mg) every 3–5 min |
| Paediatric anaphylaxis | Epinephrine 1:1000 | 0.01 mg/kg IM anterolateral thigh (max 0.5 mg) |
| Hyperkalaemia (cardiac arrest) | Calcium + Bicarbonate + Insulin/Glucose ± Salbutamol | Calcium is membrane-stabilising; insulin-glucose drives K⁺ intracellularly; salbutamol neb as adjunct; dialysis if refractory |
| LVAD failure | Epinephrine infusion + ECMO | Standard CPR may be ineffective in LVAD patients; ECMO is the primary rescue strategy per AHA 2025 |
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