Mivacron (Mivacurium)

Mivacurium is used to produce neuromuscular blockade in clinical settings requiring rapid muscle relaxation.

• Facilitation of endotracheal intubation: provides quick and predictable relaxation to allow safe airway instrumentation.
• Muscle relaxation during surgical procedures: enables controlled skeletal muscle relaxation for optimal operative conditions.
• Assistance in diagnostic procedures requiring muscle relaxation: supports procedures such as bronchoscopy where transient paralysis is needed.

• Mivacurium acts as a competitive antagonist at nicotinic acetylcholine receptors located on the motor end‑plate of skeletal muscle. By binding to these receptors without activating them, it prevents acetylcholine from triggering depolarization, thereby inhibiting transmission of nerve impulses and producing a reversible, short‑acting skeletal muscle relaxation. The drug is hydrolyzed rapidly by plasma pseudocholinesterase, which limits its duration of action and allows spontaneous recovery as enzyme activity restores neuromuscular transmission.

Mivacurium may be associated with a range of adverse reactions, varying from mild to severe.

Common Side Effects

• Flushing: transient reddening of the skin often accompanied by warmth.
• Itching (pruritus): mild skin irritation that may occur after administration.
• Bronchospasm: reversible narrowing of the airways causing wheezing.
• Hypotension: temporary drop in blood pressure.
• Tachycardia: increased heart rate.
• Nausea: feeling of sickness or urge to vomit.

Serious or Rare Side Effects

• Anaphylaxis: severe allergic reaction with potential airway compromise.
• Prolonged neuromuscular blockade: extended paralysis requiring ventilatory support.
• Malignant hyperthermia susceptibility: rapid rise in body temperature and muscle rigidity.
• Hyperkalemia: elevated blood potassium levels.
• Respiratory depression: inadequate breathing requiring assistance.

When using Mivacurium, clinicians should observe specific precautions to minimize risks and ensure safe administration.

• Assess neuromuscular function: monitor depth of block with peripheral nerve stimulator.
• Evaluate pseudocholinesterase activity: identify patients with deficiency to avoid prolonged effect.
• Avoid use in patients with known hypersensitivity to mivacurium or related compounds.
• Use caution in cardiovascular disease: monitor blood pressure and heart rate during infusion.
• Avoid concurrent administration with other neuromuscular blocking agents without appropriate monitoring.
• Store at 2-8°C: keep refrigerated, protect from light, do not freeze or shake.

Mivacurium can interact with other drugs, influencing the degree and duration of neuromuscular blockade.

Major Interactions (Avoid)

• Aminoglycoside antibiotics: potentiate blockade and may cause prolonged paralysis.
• Magnesium sulfate: enhances neuromuscular inhibition, increasing risk of respiratory failure.
• Concurrent use with other neuromuscular blocking agents: additive effects can lead to excessive muscle relaxation.

Moderate Interactions (Monitor Closely)

• Inhalational anesthetics (e.g., sevoflurane, desflurane): may prolong duration of action.
• Opioid analgesics: may require dose adjustment of mivacurium.
• Anticholinesterase agents used for reversal: can affect recovery time and necessitate careful monitoring.