Drug Monograph
Full clinical overview, indications, dosage references & safety notes.
Available forms1 form · 1 strength documentedShow all ↓
10 mg/mL Zemuron®, Esmeron®
Overview
Rocuronium (Zemuron®) is an aminosteroidal nondepolarizing neuromuscular blocking agent used in dogs and cats to produce skeletal muscle relaxation during general anesthesia. It has a rapid to intermediate onset of action and an intermediate duration of effect.
Compared with other nondepolarizing neuromuscular blockers, rocuronium has a faster onset of action than vecuronium and atracurium, being about two to three times faster than vecuronium and nearly as rapid as succinylcholine. It does not provide analgesia, sedation, or anesthesia and should be used only in adequately anesthetized patients with full monitoring and facilities for positive-pressure ventilation available.
Mechanism of Action (MOA): Rocuronium competitively antagonizes acetylcholine at cholinergic receptor sites on the motor end plate, preventing neuromuscular transmission and resulting in paralysis of striated muscles. Its effects are dose-dependent and reversible with appropriate antagonists.
Indications
Rocuronium is used in dogs and cats as a neuromuscular blocking agent to provide skeletal muscle relaxation during general anesthesia; clinical experience in veterinary patients is still relatively limited and all use is extra-label. It should only be used in adequately anesthetized patients with full monitoring and facilities for positive-pressure ventilation available.
- Muscle relaxation during surgery: Used under general anesthesia to facilitate surgical procedures requiring controlled skeletal muscle relaxation.
- Ophthalmic procedures (dogs): May be used during ophthalmic surgery to achieve a central position of the eye.
- Ventilation support: Facilitating positive-pressure ventilation at standard neuromuscular-blocking doses.
- Endotracheal intubation (cats): Facilitating endotracheal intubation in cats, where laryngeal reflexes make intubation difficult – only where rapid successful intubation can be achieved and ventilation maintained until the block wears off or is reversed.
Dosage (Reference)
Dog
In dogs, rocuronium is used as an extra-label neuromuscular blocking agent during general anesthesia. Dosage may be administered as a bolus injection followed by a continuous rate infusion (CRI) when prolonged neuromuscular blockade is required.
| Clinical use | Route | Dose | Frequency | Notes |
|---|---|---|---|---|
| Neuromuscular blocker | IV | 0.4 – 0.5 mg/kg followed by 0.2 mg/kg/hour CRI | Single bolus, then continuous infusion | Rocuronium administered in this way was effective in dogs and easily applicable to clinical practice, but that further work is required on infusion titration. |
| Ophthalmic procedures | IV | 0.03–0.05 mg/kg. | Single dose | Used with isoflurane to achieve a central position of the eye during short ophthalmic procedures. |
| Neuromuscular blockade – incremental protocol | IV | 0.4 mg/kg, followed by incremental doses of 0.16 mg/kg. | As required – when two twitches of the (TOF) train-of-four return | The 0.4 mg/kg loading dose abolished all responses to train-of-four stimulation, and blockade lasted 32.3 ± 8.2 minutes. The 0.16 mg/kg increments had a mean duration of action of 20.8 ± 4.9 minutes, and up to seven increments were shown to be non-cumulative. |
• Use only in adequately anesthetized and mechanically ventilated patients.
• Monitor paralysis with acceleromyography (train-of-four) or electromyography, and monitor heart rate and blood pressure. Recovery measured at a pelvic limb may not exclude residual blockade at the larynx.
Cat
In cats, rocuronium is used as an extra-label neuromuscular blocking agent during general anesthesia.
| Clinical use | Route | Dose | Frequency | Notes |
|---|---|---|---|---|
| Neuromuscular blocker | IV | 0.3–0.6 mg/kg | Single dose | Administer only under general anesthesia with monitoring and positive-pressure ventilation available. Apnea lasting five minutes or longer occurred in seven of eight cats given 0.6 mg/kg. |
| Endotracheal intubation (facilitation) | IV | 0.6 mg/kg | Single dose | Requires prompt successful intubation, with ventilation maintained until the effects of the block wane or are reversed. Apnea lasting five minutes or longer occurred in seven of eight cats at this dose. |
| Endotracheal intubation – lower-dose alternative | IV | 0.3 mg/kg | Single dose | May facilitate tracheal intubation, although a laryngeal response was never completely prevented. Apnea lasting five minutes or longer occurred in three of eight cats. Positive-pressure ventilation must be available. |
• Recovery of a train-of-four (TOF) ratio of 0.9 may not reliably exclude residual neuromuscular blockade.
• Reversal of neuromuscular blockade is considered prudent even when no fade can be detected by objective monitoring methods.
Warnings & Precautions
Rocuronium is a neuromuscular blocking agent that produces paralysis without providing sedation, anesthesia, or analgesia. Careful patient monitoring and ventilatory support are essential throughout administration.
- Hypersensitivity: Contraindicated in patients with known hypersensitivity to rocuronium or other neuromuscular blocking agents.
- Adequate anesthesia required: Should only be administered to adequately anesthetized patients, as rocuronium has no sedative, anesthetic, or analgesic properties.
- Mechanical ventilation: General guidance restricts rocuronium to intubated, mechanically ventilated patients, while the feline intubation protocol requires prompt successful intubation and ventilation until the block wanes or is reversed.
- Emergency support: Oxygen therapy and reversal agents should be immediately available whenever rocuronium is used.
- Renal or hepatic dysfunction: Use with caution in patients with renal or hepatic impairment. Hepatic disease may prolong the duration of action and atracurium is preferred in this group of patients; the effect of renal disease requires further investigation, and recovery was independent of renal perfusion in an experimental study in cats.
- Myasthenia gravis: Use with caution in patients with myasthenia gravis as small doses of nondepolarizing neuromuscular blocking agents may have profound effects.
- Extravasation: Accidental perivascular administration may result in local irritation.
- High-alert medication: Accidental administration of a neuromuscular blocking agent may be fatal. Use independent dose and volume verification, warning labels, and store it so that the wrong vial cannot easily be selected.
- Conditions that prolong the block: Hypothermia, acidosis and hypokalaemia will prolong the duration of action of neuromuscular blockade.
- Pregnancy and lactation: Teratogenic effects were not demonstrated in pregnant laboratory animals, but the rate of embryonic death increased, likely due to oxygen deficiency. Excretion into milk is possible but a clinical effect in offspring would likely be minimal because the drug is ionized at physiologic pH. Safety has not been established in animals – use only where the maternal benefit outweighs the potential risk to offspring.
Drug Interactions
Most clinically relevant interactions with rocuronium involve either antagonism of its neuromuscular blocking effects or enhancement and prolongation of neuromuscular blockade. Additional monitoring is recommended when used with interacting medications.
- Acetylcholinesterase inhibitors (e.g., neostigmine, pyridostigmine): Antagonize the neuromuscular blocking effects of rocuronium.
- General anesthetics: In humans, concurrent use with rocuronium can prolong the QT interval.
- Corticosteroids (e.g., dexamethasone, prednis(ol)one): May decrease rocuronium effectiveness, prolong muscle weakness, and contribute to myopathy.
- Other nondepolarizing neuromuscular blocking agents: May produce synergistic neuromuscular blocking effects.
- Succinylcholine: May accelerate onset and enhance neuromuscular blockade; rocuronium should not be administered until succinylcholine effects have subsided.
- Sugammadex: Antagonizes the effects of rocuronium and is its specific reversal agent.
- Aminoglycosides (e.g., gentamicin): May enhance or prolong neuromuscular blockade.
- Inhalation anesthetics (e.g., isoflurane): May enhance or prolong neuromuscular blockade.
- Antiarrhythmic agents (e.g., procainamide, quinidine): May enhance or prolong neuromuscular blockade.
- Bacitracin or systemic polymyxin B: May enhance or prolong neuromuscular blockade; consider therapy modification.
- Calcium channel blockers (e.g., amlodipine, diltiazem): May enhance or prolong neuromuscular blockade.
- Cyclosporine: May enhance or prolong neuromuscular blockade.
- Lincosamides (e.g., clindamycin): May enhance or prolong neuromuscular blockade.
- Lithium: May enhance or prolong neuromuscular blockade.
- Magnesium salts: May enhance or prolong neuromuscular blockade; some guidance considers parenteral magnesium sulfate with a nondepolarizing blocker contraindicated. Additive CNS depression may also occur when parenteral magnesium is used with CNS-depressant sedatives, neuromuscular blocking agents and anesthetics.
- Quinine: May enhance or prolong neuromuscular blockade; avoid combination.
- Tetracyclines (e.g., doxycycline, minocycline): May enhance or prolong neuromuscular blockade.
- Vancomycin: May enhance or prolong neuromuscular blockade.
Side Effects & Overdose
Side Effects
Rocuronium is generally well tolerated and has minimal cardiovascular and histamine-releasing effects. Most adverse effects are associated with its neuromuscular blocking activity.
- Changes in heart rate: An increase in heart rate, with mild hypertension, can occur when high doses are used; rocuronium is mildly vagolytic, and a slight, transient tachycardia is occasionally seen in people.
- Changes in blood pressure: Transient hypotension or hypertension may occur; in people these are the most common adverse reactions, reported in 2% of patients, and are transient and typically mild. In a canine clinical series the only cardiovascular effects observed were small transient increases in arterial blood pressure, but marked tachycardia and hypotension to a mean arterial pressure of 35 mmHg were reported in one dog within 10 minutes of rocuronium administration.
- Anaphylactic reactions: Severe anaphylaxis has been reported in people, and cross-reactivity between neuromuscular blocking agents should be considered; rocuronium is contraindicated in patients hypersensitive to it or to any other neuromuscular blocking agent.
- Histaminoid reactions: May occur despite the drug having minimal histamine-releasing effects.
- Injection site pain: Severe burning pain can follow injection, so give it only after a deep stage of anesthesia has been achieved.
- Management of a severe reaction: In the reported canine case, hemodynamic abnormalities that did not resolve with initial interventions were mitigated after diphenhydramine 0.8 mg/kg intravenously.
Overdose
Excessive doses may result in prolonged neuromuscular blockade with persistent paralysis and respiratory compromise requiring continued ventilatory support.
- Prolonged neuromuscular blockade: Recovery of normal neuromuscular function may be delayed.
- Respiratory paralysis: Airway protection, oxygenation, and mechanical ventilation must be maintained until adequate recovery occurs.
- Cardiovascular effects: Heart rate and blood pressure should be monitored and treated supportively as needed.
- Supportive care: Maintain ventilation, oxygenation, and adequate sedation until normal neuromuscular function is restored.
- Acetylcholinesterase inhibitors: Neostigmine with an anticholinergic agent (e.g., atropine) may be considered only after evidence of recovery is observed.
- Poison-service consultation: For a known or suspected overdose, consultation with a 24-hour poison consultation center specializing in veterinary-specific information is recommended.
Key Notes
Practical clinical points that help optimize the use of rocuronium in dogs and cats:
- Intermediate duration: Similar to vecuronium and atracurium in one, and a shorter time to spontaneous recovery than vecuronium in dogs in another. At 0.6 mg/kg it is 20 minutes in dogs, and reported feline figures range from 13 to 20 minutes.
- Favorable adverse-effect profile: Produces fewer adverse effects than succinylcholine and has minimal cardiovascular and histamine-releasing effects.
- Onset times: Complete neuromuscular blockade develops in 2 to 3 minutes after 0.4 mg/kg in dogs – a mean of 98 seconds in one canine study – and within 30 to 60 seconds in 90% of cats given 0.6 mg/kg.
- Storage: Refrigerate at 2°C to 8°C and do not freeze. Once moved to room temperature (25°C) use within 60 days; use an opened vial within 30 days. Diluted infusions are stable for 24 hours at room temperature at up to 5 mg/mL – discard any unused portion.
- Commercial injection: Each mL contains 10 mg rocuronium bromide and 2 mg sodium acetate; the isotonic solution is adjusted to pH 4 with acetic acid and/or sodium hydroxide.
