MIVACURIUM CHLORIDE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for MIVACURIUM CHLORIDE (MIVACURIUM CHLORIDE).
Mivacurium chloride is a non-depolarizing neuromuscular blocking agent that competitively binds to nicotinic acetylcholine receptors at the motor end-plate, preventing acetylcholine from binding and thereby inhibiting neuromuscular transmission. It is a mixture of stereoisomers and is rapidly hydrolyzed by plasma cholinesterase.
| Metabolism | Rapidly hydrolyzed by plasma cholinesterase (butyrylcholinesterase) to inactive metabolites: monoester and amino alcohol. Metabolism is independent of hepatic or renal function. |
| Excretion | Primarily renal excretion of unchanged drug and metabolites; approximately 90-95% eliminated via urine, with less than 5% in feces. Minor biliary excretion. |
| Half-life | Terminal elimination half-life is approximately 2 minutes (range 1-3 minutes) for the initial rapid distribution phase, and the elimination half-life is about 17-20 minutes in patients with normal renal function. Clinically, this short half-life allows for rapid recovery of neuromuscular function. |
| Protein binding | Approximately 30-40% bound to plasma proteins, primarily albumin. |
| Volume of Distribution | Volume of distribution is approximately 0.1-0.2 L/kg, indicating limited distribution primarily to extracellular fluid. This low Vd is consistent with its quaternary ammonium structure and high water solubility. |
| Bioavailability | Not applicable for oral route due to negligible absorption; only administered intravenously, thus bioavailability is 100% for IV administration. |
| Onset of Action | Intravenous: 1-3 minutes for maximum neuromuscular blockade; onset is dose-dependent, with higher doses providing faster onset (e.g., 0.15 mg/kg produces blockade within 1.5-2 minutes). |
| Duration of Action | Duration of action is approximately 15-25 minutes after a standard intubating dose (0.15 mg/kg), with clinically useful relaxation lasting 10-15 minutes. Recovery to 25% of baseline twitch height occurs in about 15-20 minutes, and to 95% recovery in 25-35 minutes. Duration is prolonged in patients with renal or hepatic impairment. |
0.15-0.25 mg/kg IV bolus for endotracheal intubation; maintenance infusion: 0.5-1.5 mcg/kg/min IV
| Dosage form | INJECTABLE |
| Renal impairment | No specific dose adjustment required; prolonged neuromuscular blockade may occur in severe renal impairment (CrCl <30 mL/min) due to reduced clearance; monitor recovery |
| Liver impairment | No specific dose adjustment for Child-Pugh A or B; in Child-Pugh C, clearance is reduced by approximately 50%, consider dose reduction and prolonged monitoring of neuromuscular function |
| Pediatric use | Children 2-12 years: 0.2 mg/kg IV bolus; maintenance infusion: 1.5-2 mcg/kg/min IV. Infants 1-24 months: 0.25 mg/kg IV bolus; maintenance infusion: 3-5 mcg/kg/min IV |
| Geriatric use | Elderly patients (>65 years) may have prolonged duration of action; consider dose reduction by 10-20% and monitor carefully for delayed recovery of neuromuscular function |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for MIVACURIUM CHLORIDE (MIVACURIUM CHLORIDE).
| Breastfeeding | No data on excretion in human milk. M/P ratio unknown. Use with caution in breastfeeding women; consider risk of infant exposure to neuromuscular blocking agent. |
| Teratogenic Risk | Mivacurium is a depolarizing neuromuscular blocking agent. Animal studies have not been conducted. No well-controlled human studies exist. In first trimester, risk cannot be ruled out. In second and third trimesters, use only if clearly needed; may cross placenta in small amounts. Potential fetal effects include transient neuromuscular blockade if used near delivery. |
■ FDA Black Box Warning
Mivacurium should be administered in carefully adjusted doses by or under the supervision of experienced clinicians who are familiar with the drug's actions and with appropriate neuromuscular monitoring. Resuscitative drugs and equipment must be immediately available. Do not use in patients with low or atypical plasma cholinesterase activity, as prolonged paralysis may occur.
| Serious Effects |
["Known hypersensitivity to mivacurium or other neuromuscular blocking agents","Known low or atypical plasma cholinesterase activity"]
| Precautions | ["Risk of prolonged neuromuscular blockade in patients with genetic deficiency of plasma cholinesterase (atypical enzyme) or reduced enzyme activity (e.g., severe liver disease, pregnancy, burns, or use of anticholinesterases)","May cause histamine release leading to hypotension, tachycardia, and bronchospasm, especially with rapid bolus administration","Use with caution in patients with cardiovascular disease, bronchial asthma, or those with anticipated difficult airway"] |
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| Fetal Monitoring |
| Monitor maternal vital signs, oxygen saturation, and neuromuscular function with a nerve stimulator. Assess for prolonged neuromuscular blockade. Fetal heart rate monitoring should be considered if used during cesarean section. |
| Fertility Effects | No data on effects on human fertility. Animal studies not conducted. Theoretical risk of interference with neuromuscular function in reproductive tissues, but clinical significance unknown. |