ZEMURON
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ZEMURON (ZEMURON).
Rocuronium is a nondepolarizing neuromuscular blocking agent that competitively binds to nicotinic acetylcholine receptors at the motor endplate, preventing acetylcholine from inducing muscle contraction.
| Metabolism | Primarily hepatic via CYP3A4; minor metabolism via CYP2C9; also undergoes deacetylation. Approximately 30% excreted unchanged in urine. |
| Excretion | Primarily renal (70-80% as unchanged drug and metabolites) and biliary (20-30% as unchanged drug and metabolites). |
| Half-life | Terminal elimination half-life is approximately 2.3 hours (range 1.7-3.1 hours) in adults with normal renal function. Clinical context: May be prolonged in hepatic or renal impairment. |
| Protein binding | Approximately 30% bound, mainly to albumin and globulins. |
| Volume of Distribution | Vd: 0.3-0.6 L/kg. Clinical meaning: Indicates extensive distribution into extracellular fluid. |
| Bioavailability | Not applicable; only administered IV, thus bioavailability is 100%. |
| Onset of Action | IV: 60-90 seconds (intubating dose 0.6 mg/kg). |
| Duration of Action | IV: Approximately 30-45 minutes (clinical duration of neuromuscular block) after initial intubating dose; longer with higher doses or after multiple maintenance doses. Recovery to 25% of control twitch height: ~20-30 min. |
| Molecular Weight | 609.8 Da (as rocuronium bromide) |
0.6-1.2 mg/kg IV bolus for intubation; maintenance 0.1-0.2 mg/kg IV as needed for neuromuscular blockade.
| Dosage form | INJECTABLE |
| Renal impairment | No specific dose adjustment; prolonged effect may occur in renal impairment; monitor recovery. |
| Liver impairment | Child-Pugh A/B: No adjustment; Child-Pugh C: Caution, may have prolonged duration. |
| Pediatric use | Infants 1-12 months: 0.15 mg/kg IV; Children 1-12 years: 0.6 mg/kg IV for intubation; maintenance 0.075-0.125 mg/kg IV. |
| Geriatric use | Consider lower doses; increased sensitivity and prolonged recovery; monitor neuromuscular function. |
| 1st trimester | Avoid unless absolutely necessary; potential for fetal bradycardia and hypoxia. |
| 2nd trimester | Use only if clearly needed; may cause fetal paralysis if given near delivery. |
| 3rd trimester | Use caution; risk of neonatal respiratory depression and prolonged neuromuscular blockade. |
Clinical note
Comprehensive clinical and safety monograph for ZEMURON (ZEMURON).
| Placental transfer | Crosses placenta in small amounts; greater transfer may occur with high maternal doses or prolonged use. |
| Breastfeeding | Excreted into breast milk in very small amounts; unlikely to affect nursing infant due to poor oral bioavailability. Use with caution. |
| Lactation Rating |
■ FDA Black Box Warning
Appropriate administration and monitoring of rocuronium require the availability of resuscitative equipment and trained personnel. Use only by individuals skilled in airway management and respiratory support.
| Serious Effects |
Hypersensitivity to rocuronium or any componentKnown or suspected malignant hyperthermia susceptibility
| Precautions | Can cause anaphylaxis, May potentiate neuromuscular blockade in patients with neuromuscular diseases (e.g., myasthenia gravis), Risk of residual paralysis, Acid-base or electrolyte disturbances may alter effects, Prolonged use in ICU may result in prolonged paralysis and myopathy |
| Food/Dietary | No known food interactions. Avoid magnesium-containing antacids or magnesium supplements before use, as they may potentiate neuromuscular blockade. |
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| L3 (Moderately Safe) |
| Teratogenic Risk | Pregnancy Category C. No adequate and well-controlled studies in pregnant women. Fetal risk cannot be ruled out. Use only if potential benefit justifies potential risk to fetus. In animal studies, no teratogenic effects observed at doses up to 0.2 mg/kg IV in rats and rabbits. |
| Fetal Monitoring | Monitor maternal vital signs, oxygen saturation, and neuromuscular function with train-of-four monitoring. Fetal heart rate monitoring recommended if used during cesarean section. |
| Fertility Effects | No human data on fertility effects. In animal studies, no impairment of fertility observed at doses up to 0.2 mg/kg IV. |
| Clinical Pearls | Zemuron (rocuronium) is a non-depolarizing neuromuscular blocker used for rapid sequence intubation (RSI) at 0.6-1.2 mg/kg IV. Onset is 60-90 seconds; duration 30-40 min. Reversal with sugammadex (2-4 mg/kg) is preferred over neostigmine for rapid recovery. Avoid in patients with neuromuscular diseases (e.g., myasthenia gravis) due to prolonged effect. Store in refrigerator (2-8°C) but stable at room temperature for up to 30 days. |
| Patient Advice | This medication causes temporary paralysis and you will not be able to move or breathe on your own; a breathing machine will support you. · You will receive sedation and pain medication alongside this drug to ensure you are comfortable and unaware. · The effects are fully reversible, and your breathing will return to normal once the drug is stopped or reversed. · Inform your doctor if you have muscle weakness, kidney disease, or electrolyte imbalances, as these may affect the drug's action. |