MIVACRON
Clinical safety rating: caution
Comprehensive clinical and safety monograph for MIVACRON (MIVACRON).
Mivacurium is a bis-benzylisoquinoline neuromuscular blocking agent that acts as a competitive antagonist at nicotinic acetylcholine receptors at the neuromuscular junction, leading to muscle paralysis.
| Metabolism | Mivacurium is rapidly hydrolyzed by plasma pseudocholinesterase (butyrylcholinesterase) to inactive metabolites; the rate of hydrolysis is slower than that of succinylcholine but faster than other nondepolarizing agents. |
| Excretion | Primarily renal (approximately 80-90% as unchanged drug and metabolites) and biliary (small fraction, <20% as metabolites). |
| Half-life | Terminal elimination half-life is approximately 2-3 minutes; clinically, rapid clearance via plasma cholinesterase results in short duration. |
| Protein binding | Approximately 40-50% bound to plasma proteins (primarily albumin). |
| Volume of Distribution | 0.2-0.3 L/kg; reflects limited extravascular distribution. |
| Bioavailability | Intravenous: 100%. |
| Onset of Action | Intravenous: 1-2 minutes for intubating doses (0.15-0.2 mg/kg). |
| Duration of Action | Intravenous: 15-20 minutes (clinical recovery to 25% of control twitch), dependent on dose and plasma cholinesterase activity. |
0.15-0.2 mg/kg IV bolus for intubation; maintenance infusion 9-10 mcg/kg/min
| Dosage form | SOLUTION |
| Renal impairment | No dose adjustment required for mild to moderate renal impairment; use with caution in severe renal impairment (GFR <30 mL/min) as prolonged effects may occur |
| Liver impairment | No specific Child-Pugh based guidelines; use with caution in significant hepatic dysfunction as metabolism may be impaired |
| Pediatric use | 2-12 years: 0.15 mg/kg IV bolus; continuous infusion 14 mcg/kg/min; infants 1-24 months: 0.15 mg/kg IV bolus, infusion 12 mcg/kg/min |
| Geriatric use | Consider using lower end of dosing range (0.15 mg/kg IV bolus) due to decreased clearance and prolonged duration of action |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for MIVACRON (MIVACRON).
| Breastfeeding | It is unknown if mivacurium is excreted in human milk. No studies on M/P ratio. Due to short half-life and low oral bioavailability, risk to breastfeeding infant is likely low. However, caution is advised. Use only if clearly needed. |
| Teratogenic Risk | Mivacron (mivacurium) is a nondepolarizing neuromuscular blocker. No adequate and well-controlled studies in pregnant women. Animal studies have not shown teratogenic effects. However, use during pregnancy only if clearly needed. In the first trimester, theoretical risks exist but no data. In second and third trimesters, use only if necessary for anesthesia, with caution due to potential fetal effects from maternal hypotension or hypoxia. Placental transfer is minimal at clinical doses. |
■ FDA Black Box Warning
Mivacurium is not recommended for use in patients with known or suspected plasma pseudocholinesterase deficiency because prolonged neuromuscular blockade may occur.
| Serious Effects |
["Known hypersensitivity to mivacurium or other bis-benzylisoquinoline neuromuscular blocking agents","Known or suspected plasma pseudocholinesterase deficiency"]
| Precautions | ["Risk of histamine release leading to hypotension, tachycardia, bronchospasm, and cutaneous flushing, especially with rapid bolus doses","Use caution in patients with cardiovascular disease, renal impairment, hepatic impairment, or electrolyte disorders","Monitor neuromuscular function with a nerve stimulator","Resuscitative equipment and drugs must be immediately available"] |
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| Fetal Monitoring | Monitor maternal vital signs, oxygen saturation, and neuromuscular blockade (train-of-four monitoring). Fetal heart rate monitoring during cesarean section. Observe for maternal hypotension and hypoxia which could affect fetus. |
| Fertility Effects | No human data on fertility effects. Animal studies have not shown impaired fertility. However, limited data. |