Top 50 Emergency Drugs for FRCEM

Emergency pharmacology is examined repeatedly in MRCEM SBA, FRCEM SBA and FRCEM OSCE. Candidates are rarely tested on isolated drug facts. They are tested on choosing the right drug, in the right patient, by the right route, at the right time, while avoiding the dangerous alternative. In the emergency department, the same principles matter even more.

A useful revision approach is to learn drugs by scenario rather than alphabetically: cardiac arrest, peri-arrest arrhythmia, anaphylaxis, status epilepticus, procedural sedation, sepsis, toxicology, acute coronary syndrome, hyperkalaemia and major haemorrhage. That mirrors both real ED practice and exam design.

The 50 drugs covered here are: adrenaline, noradrenaline, amiodarone, lidocaine, magnesium sulphate, atropine, adenosine, calcium chloride, calcium gluconate, sodium bicarbonate, aspirin, glyceryl trinitrate, clopidogrel, ticagrelor, heparin, tenecteplase, furosemide, ketamine, propofol, midazolam, lorazepam, diazepam, fentanyl, morphine, paracetamol, ibuprofen, ondansetron, metoclopramide, haloperidol, droperidol, salbutamol, ipratropium, hydrocortisone, dexamethasone, ceftriaxone, piperacillin-tazobactam, gentamicin, vancomycin, aciclovir, naloxone, flumazenil, digoxin-specific antibody fragments, activated charcoal, N-acetylcysteine, insulin with dextrose, glucagon, levetiracetam, phenytoin or fosphenytoin, valproate and tranexamic acid.

Doses and pathways vary slightly by local formulary, specialty ownership and patient factors. For exams, use mainstream UK practice aligned with Resuscitation Council UK, RCEM, NICE, BTS/SIGN, TOXBASE and standard NHS pathways. In clinical work, always check local guidance, especially for antimicrobials, sedation and toxicology.

Why These Drugs Matter for FRCEM

Drug errors in emergency medicine are usually errors of context rather than memory. Common examples include:

• giving adrenaline too early in shockable arrest
• using IV adrenaline in routine anaphylaxis
• giving adenosine to an irregular broad-complex tachycardia
• forgetting that calcium stabilises the myocardium but does not lower potassium
• delaying second-line treatment in status epilepticus
• over-reversing an opioid-dependent patient with naloxone
• using flumazenil in mixed overdose or benzodiazepine dependence

These are classic SBA traps and real ED hazards. Strong candidates know indication, route, dose, sequence, contraindications, monitoring and escalation.

Key Definitions

• First-line drug: the standard initial treatment in a given scenario.
• Alternative drug: used when first-line treatment is unavailable, contraindicated or has failed.
• Peri-arrest: critically unwell with imminent risk of cardiac arrest.
• Shockable arrest rhythm: ventricular fibrillation or pulseless ventricular tachycardia.
• Non-shockable arrest rhythm: pulseless electrical activity or asystole.
• Status epilepticus: prolonged seizure activity or recurrent seizures without recovery; in practice, treat early and escalate promptly.
• Procedural sedation: use of sedative and analgesic drugs to facilitate painful or distressing procedures with full monitoring and airway readiness.
• Membrane stabilisation in hyperkalaemia: IV calcium to reduce arrhythmic risk; it does not remove potassium.
• Toxidrome: a recognisable pattern of poisoning features suggesting a drug class.

Essential Pathophysiology

Most emergency drugs are easiest to remember if linked to the physiological problem they correct.

• Adrenaline increases coronary and cerebral perfusion in arrest and reverses vasodilation and bronchospasm in anaphylaxis.
• Amiodarone and lidocaine suppress refractory ventricular arrhythmia in shockable arrest.
• Adenosine transiently blocks AV nodal conduction and terminates AV node-dependent SVT.
• Atropine reduces vagal influence and may improve symptomatic bradycardia.
• Calcium stabilises the cardiac membrane in hyperkalaemia.
• Insulin with dextrose shifts potassium intracellularly.
• Magnesium treats torsades de pointes and has roles in severe asthma and eclampsia.
• Benzodiazepines enhance GABA activity and terminate seizures.
• Ketamine provides dissociative sedation and analgesia while usually preserving airway reflexes better than many alternatives.
• Naloxone reverses opioid-induced respiratory depression.
• N-acetylcysteine replenishes glutathione and limits paracetamol hepatotoxicity.
• Tranexamic acid reduces fibrinolysis in major haemorrhage.

Clinical Presentation

The same drug may appear in very different presentations. High-yield ED scenarios include:

• persistent VF after the third shock
• anaphylaxis with wheeze, stridor or hypotension
• stable regular narrow-complex tachycardia
• symptomatic bradycardia with hypotension or syncope
• hyperkalaemia with ECG changes
• status epilepticus with or without IV access
• agitated trauma patient requiring procedural sedation
• opioid overdose with reduced respiratory rate
• paracetamol overdose
• sepsis or suspected meningitis
• STEMI, ACS or acute pulmonary oedema
• major trauma or postpartum haemorrhage

Red Flags and High-Risk Features

• airway compromise, stridor, severe bronchospasm or shock in anaphylaxis
• persistent VF/pulseless VT after three shocks
• irregular broad-complex tachycardia
• complete heart block or unstable bradycardia
• hyperkalaemia with ECG changes
• ongoing seizure beyond first-line benzodiazepine therapy
• reduced GCS with respiratory depression
• suspected TCA toxicity with QRS widening
• digoxin toxicity with arrhythmia or hyperkalaemia
• severe sepsis, meningococcal disease or suspected encephalitis
• major haemorrhage or haemodynamic instability

Differential Diagnosis

Drug choice depends on correct syndrome recognition.

• SVT versus atrial fibrillation versus VT
• anaphylaxis versus isolated urticaria versus asthma
• opioid overdose versus hypoglycaemia versus intracranial event
• status epilepticus versus psychogenic non-epileptic seizure
• hyperkalaemia versus broad-complex rhythm from another cause
• septic shock versus cardiogenic shock versus haemorrhagic shock
• TCA overdose versus sodium channel blocker toxicity from another agent
• agitated delirium versus psychosis versus hypoxia versus hypoglycaemia

Initial ED Assessment

Before any emergency drug, apply an ABCDE approach.

• Airway: patency, suction, adjuncts, need for RSI or anaesthetic support.
• Breathing: respiratory rate, oxygen saturation, work of breathing, capnography where relevant.
• Circulation: pulse, blood pressure, ECG, IV/IO access, shock state, haemorrhage.
• Disability: GCS, pupils, glucose, seizure activity, agitation.
• Exposure: rash, trauma, temperature, track marks, toxidrome clues.

Immediate bedside actions often run in parallel with drug treatment:

• defibrillation in shockable arrest
• oxygen only when indicated, not automatically in all ACS patients
• ECG before and after arrhythmia treatment where possible
• glucose in any reduced consciousness or seizure
• senior help early for sedation, toxicology, peri-arrest care and unstable arrhythmia

Investigations

• 12-lead ECG
• venous or arterial blood gas including potassium and lactate
• capillary blood glucose
• FBC, U&Es, renal function, LFTs, CRP
• troponin where indicated
• paracetamol level, salicylate level and other toxicology tests as indicated
• blood cultures before antibiotics if this does not delay treatment
• pregnancy test where relevant
• CXR, CT, CT head or CT aortogram depending on presentation
• drug levels where useful, for example digoxin

Management in the Emergency Department

Use a scenario-based framework. For each drug, know indication, adult dose, route, major cautions and what to do next if it fails.

1. Cardiac arrest and peri-arrest drugs

Adrenaline

• Cardiac arrest: 1 mg IV/IO of 1:10,000.
• Non-shockable arrest: give as soon as access obtained.
• Shockable arrest: give after the third shock, then every 3-5 minutes.
• Anaphylaxis: 500 micrograms IM of 1 mg/mL (1:1000) into the anterolateral thigh. Repeat after 5 minutes if needed.
• IV adrenaline in anaphylaxis is reserved for experienced clinicians with full monitoring in refractory shock/peri-arrest settings.
• Exam trap: route and concentration change completely with indication.

Amiodarone

• Persistent VF/pulseless VT: 300 mg IV/IO after the third shock.
• If still refractory: 150 mg IV/IO after the fifth shock.
• Not for asystole or PEA.
• Caution: hypotension and bradycardia, especially outside arrest.

Lidocaine

• Alternative antiarrhythmic if amiodarone is unavailable or unsuitable.
• 100 mg IV/IO after the third shock, then 50 mg after the fifth shock if needed.
• Do not routinely combine with amiodarone in the same arrest algorithm.

Magnesium sulphate

• Torsades de pointes: 2 g IV.
• In a perfusing patient, often infused over 10-15 minutes.
• In arrest or peri-arrest, may be given more rapidly.
• Also used in severe or life-threatening asthma and in eclampsia.

Atropine

• Symptomatic bradycardia: 500 micrograms IV, repeated every 3-5 minutes to a total of 3 mg.
• Less likely to work in high-grade AV block, infranodal disease or transplanted heart.
• If ineffective or patient remains unstable, escalate early to pacing and/or vasoactive support such as adrenaline infusion according to local peri-arrest guidance.

Adenosine

• Use after vagal manoeuvres for stable regular narrow-complex SVT.
• Give as a rapid IV bolus through a large proximal vein followed by flush.
• Sequence: 6 mg, then 12 mg, then 12 mg if needed.
• May be considered in selected regular monomorphic broad-complex tachycardia if SVT with aberrancy is likely and senior oversight is present.
• Do not use in irregular broad-complex tachycardia or pre-excited AF.
• If uncertain whether broad-complex tachycardia is VT, treat as VT and seek senior help.
• Transient flushing, chest tightness and dyspnoea are expected.

Noradrenaline

• First-line vasopressor in many forms of distributive shock, especially septic shock after fluid resuscitation where appropriate.
• Usually given as a titrated infusion with continuous monitoring.
• Central access is preferred, but short-term peripheral vasopressor use may be acceptable under local policy with close observation.
• Exam point: this is an ICU-level drug that may be started in ED, but it is not a routine bolus treatment for hypotension.

2. Hyperkalaemia and metabolic emergency drugs

Calcium chloride and calcium gluconate

• Indication: hyperkalaemia with ECG changes.
• Common UK options:
  • 10 mL of 10% calcium chloride IV, ideally via secure or central access
  • 30 mL of 10% calcium gluconate IV, often preferred peripherally
• Repeat if ECG changes persist.
• Calcium stabilises the myocardium. It does not reduce serum potassium.
• Then give potassium-shifting therapy and address elimination.
• Local protocols vary slightly; know the principle and your formulary.

Insulin with dextrose

• Used after membrane stabilisation in significant hyperkalaemia.
• Common adult regimen: soluble insulin 10 units IV with glucose according to local protocol.
• Check glucose before treatment and monitor for several hours afterwards.
• Exam trap: insulin lowers potassium by shifting it intracellularly; it does not remove total body potassium.

Salbutamol

• Asthma/COPD exacerbation: nebulised 5 mg, repeated as needed.
• Hyperkalaemia: high-dose nebulised salbutamol may be used as adjunctive potassium-shifting therapy.
• Not a substitute for calcium in hyperkalaemia with ECG changes.

Sodium bicarbonate

• Not part of routine ALS and not a generic prolonged-arrest drug.
• High-yield indication: TCA overdose with QRS widening, ventricular arrhythmia, hypotension or seizures.
• Also considered in selected severe hyperkalaemia with significant metabolic acidosis.
• In TCA toxicity, the aim is sodium loading and alkalinisation; use toxicology guidance and local protocol.
• Exam trap: if the stem says overdose, hypotension, seizures and broad QRS after amitriptyline, think sodium bicarbonate.

3. Acute coronary syndrome, STEMI and acute cardiology drugs

Aspirin

• ACS: 300 mg orally as soon as possible unless contraindicated.
• Check for true allergy or active major bleeding.
• Exam trap: aspirin is standard in suspected ACS even before troponin result.

Ticagrelor and clopidogrel

• Used as part of dual antiplatelet therapy according to ACS pathway.
• Ticagrelor loading dose is commonly 180 mg orally.
• Clopidogrel loading varies by indication and pathway.
• For exams, know that antiplatelet choice is often pathway-led and may differ in STEMI, NSTEMI, stroke/TIA and after PCI.

Heparin

• Used in ACS, VTE and some specialist pathways.
• Unfractionated heparin or LMWH choice depends on indication and local protocol.
• Do not assume all chest pain gets heparin in ED.

Glyceryl trinitrate

• Useful for ischaemic chest pain and acute pulmonary oedema, especially if hypertensive.
• Routes: sublingual or IV infusion.
• Avoid or use extreme caution in hypotension, severe aortic stenosis, recent phosphodiesterase-5 inhibitor use and suspected right ventricular infarction.

Tenecteplase

• Used for thrombolysis in selected STEMI pathways where PCI is not available within target time, and in some other specialist indications.
• Weight-based IV bolus.
• Major contraindications include active bleeding, previous intracranial haemorrhage and many recent major surgery or stroke scenarios.
• Exam point: in the UK, primary PCI is preferred where available; thrombolysis is pathway-dependent.

Furosemide

• Useful in acute pulmonary oedema when fluid overload is present.
• Typical IV dose often 40-80 mg, adjusted for prior use and renal function.
• Nitrates and ventilatory support may be more immediately important than diuretics in hypertensive pulmonary oedema.
• Exam trap: not every breathless heart failure patient needs immediate furosemide.

4. Sedation, agitation, analgesia and antiemetic drugs

Ketamine

• High-yield procedural sedation drug in ED.
• Dissociative sedation: commonly 1-1.5 mg/kg IV or 4 mg/kg IM.
• Provides analgesia and amnesia.
• Useful in haemodynamically fragile patients compared with some alternatives, but not risk-free.
• Adverse effects: emergence reaction, vomiting, hypersalivation, laryngospasm, transient hypertension and tachycardia.
• Requires full sedation governance: consent where possible, fasting considerations, monitoring, capnography, airway equipment and recovery observation.

Propofol

• Effective sedative for short procedures in experienced hands.
• Rapid onset and offset.
• Major risks: hypotension, apnoea and loss of airway reflexes.
• Exam point: excellent drug, but only with appropriate expertise, monitoring and airway readiness.

Midazolam

• Used for sedation and seizure control.
• In seizures, buccal or IM midazolam is useful when IV access is not available.
• Can cause respiratory depression, especially with opioids or alcohol.

Fentanyl and morphine

• Both are titratable opioid analgesics.
• Fentanyl has rapid onset and is often favoured for procedural analgesia.
• Morphine remains common for severe pain.
• Monitor respiratory rate, sedation level and blood pressure.
• Consider smaller doses in older