Neuromuscular blocker
Rocuronium
Also called roc
Indications
- Rapid sequence intubation, especially when succinylcholine is contraindicated (hyperkalemia, burns or crush days old, denervation, myopathy, malignant hyperthermia risk)
- Routine tracheal intubation and relaxation during surgery
- Paralysis during mechanical ventilation for dyssynchrony, severe ARDS or raised ICP, by bolus or infusion; long-term ICU use is not well studied
- Refractory shivering during targeted temperature management (off-label)
Dosing
Rocuronium drip card and mL/h converterStart: 8–12 mcg/kg/min after an intubating dose
| Where | Dose |
|---|---|
| Airway and RSI | Rocuronium: 1–1.2 mg/kg for RSI (0.6 for routine); reverse with sugammadex 16 mg/kg |
On the quick cards
- Rocuronium (Zemuron)EMS Field Drugs: Airway, RSI and sedation: nondepolarizing paralytic
- Airway and RSIPush and Emergency Meds: Induction, paralysis and post-intubation boluses
Mechanism of action
Rocuronium is a competitive antagonist at the postjunctional nicotinic acetylcholine receptor. It occupies the acetylcholine sites on the α subunits without opening the channel, and blocking one of the two sites keeps the channel shut, so the end-plate potential stays below threshold and the fiber does not contract. Block of prejunctional nicotinic receptors that mobilize acetylcholine causes fade with train-of-four and tetanic stimulation. Neostigmine can overcome the block by raising acetylcholine, and sugammadex ends it by encapsulating the drug.
Pharmacology
- Neuromuscular: intermediate-acting block with fade and post-tetanic potentiation; low potency (ED95 about 0.3 mg/kg) means many molecules are given, which speeds onset
- Cardiovascular: little effect; a slight vagolytic action at high doses may raise heart rate (more than vecuronium, less than pancuronium); no meaningful histamine release
- Respiratory: apnea once the diaphragm is blocked; no direct airway effect
- CNS: none; it does not cross the blood-brain barrier, so a paralyzed patient can be awake and in pain
- Other: potentiated by volatile anesthetics, aminoglycosides, vancomycin, magnesium, lithium, acidosis and hypothermia; resisted after burns or denervation and with chronic phenytoin or carbamazepine
Pharmacokinetics
| Onset | Maximal block 1.0 min after 1.2 mg/kg and 1.8 min after 0.6 mg/kg (label medians); intubating conditions in about 60–90 s |
|---|---|
| Duration | Clinical duration (to 25% recovery) about 31 min after 0.6 mg/kg and 58–67 min after 0.9–1.2 mg/kg; can exceed 2 h |
| Half-life | About 1.4 h in adults; 2.4 h in kidney failure and 4.3 h in liver dysfunction |
| Distribution | Vd about 0.25 L/kg (extracellular fluid), about double in liver disease; umbilical levels 18% of maternal |
| Protein binding | About 30% |
| Metabolism | Minimal; 17-desacetylrocuronium, with about a twentieth of the potency, is rarely detected |
| Clearance | About 0.25 L/kg/h (4 mL/kg/min), roughly halved in liver dysfunction and kidney failure |
| Elimination | Mainly hepatic uptake and biliary excretion of unchanged drug; up to about 40% appears in urine within 24 h |
| Organ failure | After a single dose, clinical duration is about 1.5 times longer in liver disease, similar in kidney failure and slightly longer in older adults |
Chemistry
- Monoquaternary aminosteroid on an androstane nucleus: a 2-morpholine ring (tertiary amine), a 3-hydroxyl, a 17-acetate and a charged 16-N-allyl pyrrolidinium head
- Derived from vecuronium: the 3-hydroxyl leaves no 3-desacetyl metabolite and keeps it stable in solution, and the changed side groups lower potency, which speeds onset
- Single isomer with the fixed stereochemistry of the steroid nucleus; the permanent charge makes it water soluble with little lipid solubility
- 10 mg/mL solution buffered to pH 4 with acetate and made isotonic with sodium chloride; precipitates with alkaline drugs such as thiopental and is incompatible in the line with others, including dexamethasone, furosemide, insulin and vancomycin
- Refrigerate at 2–8 °C; at room temperature use within 60 days, and opened vials within 30 days
Adverse effects and cautions
In the one-pagers
- Airway and RSIRSI drugs: Sugammadex reverses rocuronium or vecuronium; 16 mg/kg reverses rocuronium immediately. Watch for anaphylaxis, bradycardia; backup contraception for 7 days.
- Asthma and COPD ExacerbationsIntubating severe asthma: Rapid sequence: ketamine 1–2 mg/kg (bronchodilates, less hypotension) or propofol, with rocuronium 1–1.2 mg/kg or succinylcholine
- Mass Casualty Triage and Incident CommandCBRNE: decontamination, nerve agents and radiation: Nerve agents inhibit acetylcholinesterase. Vapor acts in seconds to minutes: miosis, rhinorrhea and chest tightness, then bronchorrhea, bronchospasm, fasciculations, seizures and apnea. Liquid on skin can take up to 18 hours to cause systemic effects (Merck 2026). In Tokyo, over 20% of St Luke's staff had symptoms of secondary exposure (Ohbu 1997
- Paramedic Practice: Safety, Quality, Leadership and CommunicationChecks, storage and controlled drugs: Heat. Ambulance and aircraft compartments routinely exceed controlled room temperature: one 2025 UK study logged up to 46.8 °C in a helicopter, with indoor storage protecting against cold much better than against heat (Maait and Phillipson). Studies it cites found lorazepam degrading after 120 days on EMS units, atropine and naloxone degrading with heat, and 1
- Toxidromes and AntidotesCarbon monoxide, cyanide, methemoglobin and organophosphates: Organophosphates inhibit acetylcholinesterase, producing muscarinic, nicotinic (fasciculations, weakness, paralysis) and CNS effects. The inhibited enzyme 'ages' into a permanent form, while carbamates release it within about 48 h (Merck). Atropinize to a clear chest, HR over 80 and SBP over 80, then infuse 10–20% of the loading dose pe
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Sources
- FDA label: rocuronium bromide, Hospira (2025)
- Esmeron prescribing information, MSD (2019)
- PubChem: rocuronium
For education and exam preparation only. Follow your institution’s protocols. Typical adult values for study. Follow your local protocols and medical direction.