Overdosage with neuromuscular blocking agents may result in neuromuscular blockade beyond the time needed for surgery and anesthesia. The primary treatment is maintenance of a patent airway and controlled ventilation until recovery of normal neuromuscular function is assured.
Once recovery from neuromuscular block begins, further recovery may be facilitated by administration of a cholinesterase inhibitor (e.g., neostigmine, edrophonium) in conjunction with an appropriate cholinergic inhibitor. Cholinesterase inhibitors should not be administered when complete neuromuscular blockade is evident or suspected because the reversal of paralysis may not be sufficient to maintain a patent airway and support an appropriate level of spontaneous ventilation.
- Neostigmine: Administration of 0.04 to 0.07 mg/kg of neostigmine at approximately 10% recovery from neuromuscular blockade (range: 0 to 15%) produced 95% recovery of the muscle twitch response and a T4:T1 ratio ≥ 70% in an average of 9 to 10 minutes. The times from 25% recovery of the muscle twitch response to a T4:T1 ratio ≥ 70% following these doses of neostigmine averaged 7 minutes. The mean 25% to 75% recovery index following reversal was 3 to 4 minutes.
- Edrophonium: Administration of 1 mg/kg of edrophonium at approximately 25% recovery from neuromuscular blockade (range: 16% to 30%) produced 95% recovery and a T4:T1 ratio ≥ 70% in an average of 3 to 5 minutes.
For providers treating patients treated with cholinesterase inhibitors:
- Use a peripheral nerve stimulator to evaluate recovery and antagonism of neuromuscular blockade.
- Evaluate for evidence of adequate clinical recovery (e.g., 5-second head lift and grip strength).
- Support ventilation until adequate spontaneous ventilation has resumed.
The onset of antagonism may be delayed in the presence of debilitation, cachexia, carcinomatosis, and the concomitant use of certain broad spectrum antibiotics, or anesthetic agents and other drugs which enhance neuromuscular block or separately cause respiratory depression [see Drug Interactions (7.1)]. Under such circumstances the management is the same as that of prolonged neuromuscular block.