Can you use succinylcholine with myasthenia gravis? A critical analysis

October 9, 2025 •

4 min read

According to anesthesia guidelines, patients with myasthenia gravis are resistant to the effects of succinylcholine and highly sensitive to non-depolarizing neuromuscular blocking agents. This unique pharmacological profile makes the decision to use succinylcholine with myasthenia gravis a careful clinical consideration, often favoring alternative medications.

Quick Summary

Patients with myasthenia gravis exhibit resistance to succinylcholine, necessitating higher doses for effective paralysis. This unpredictable response makes non-depolarizing agents, used cautiously with specific reversal strategies, generally the safer choice during anesthesia.

Key Points

Resistance to Succinylcholine: Myasthenia gravis patients have fewer acetylcholine receptors, making them resistant to the effects of succinylcholine and requiring higher doses for muscle relaxation.
Sensitivity to Nondepolarizing Agents: Conversely, MG patients are highly sensitive to nondepolarizing neuromuscular blockers like rocuronium, necessitating significantly lower doses to avoid prolonged paralysis.
Unpredictable Paralysis: Using succinylcholine in MG carries the risk of an unpredictable or prolonged paralytic effect, especially with repeat dosing, which can result in a phase II block.
Rocuronium-Sugammadex is Preferred: Many clinicians now prefer to use a reduced dose of rocuronium with the reversal agent sugammadex, as it offers a more controllable and reliably reversible neuromuscular block.
Crisis Management: Clinicians must be vigilant in differentiating between a myasthenic crisis (disease exacerbation) and a cholinergic crisis (medication overdose) in the perioperative setting, as treatments differ significantly.
Expert Anesthetic Care is Critical: Managing anesthesia and neuromuscular blockade in patients with myasthenia gravis requires specialized knowledge and careful monitoring to minimize the risk of respiratory complications.

The Pharmacological Dilemma: Succinylcholine vs. Nondepolarizing Agents in MG

Myasthenia gravis (MG) is an autoimmune disorder that primarily affects the neuromuscular junction (NMJ), the site where nerve impulses trigger muscle contractions. The disease is characterized by antibodies attacking and destroying the nicotinic acetylcholine receptors (AChRs) on the postsynaptic membrane. This reduction in available receptors disrupts normal neuromuscular transmission, leading to muscle weakness and fatigue. Anesthesiologists must carefully consider this altered physiology when selecting neuromuscular blocking agents (NMBAs) for procedures requiring muscle relaxation.

NMBAs are classified into two main types: depolarizing and nondepolarizing. Succinylcholine is the only depolarizing NMBA in clinical use. It mimics the neurotransmitter acetylcholine (ACh) and binds to AChRs, causing persistent depolarization of the motor endplate. This initially causes muscle fasciculations (twitching) followed by flaccid paralysis. However, in patients with MG, the reduced number of functional AChRs means that a higher dose of succinylcholine is required to achieve the same level of paralysis as in a healthy individual.

In contrast, nondepolarizing NMBAs like rocuronium and vecuronium act as competitive antagonists, blocking the AChRs without activating them. With fewer AChRs present in MG patients, nondepolarizing agents have a much more profound effect, meaning smaller doses can lead to significant muscle weakness and prolonged paralysis.

Clinical Considerations for Using Succinylcholine in MG

While not strictly contraindicated in MG in the same way as in conditions with receptor upregulation (e.g., severe burns or crush injuries, which pose a significant hyperkalemia risk), the use of succinylcholine is not straightforward. Clinicians face several challenges and risks:

Increased Dosing Requirements: Due to receptor downregulation, a standard dose of succinylcholine will be less effective in an MG patient. Anesthesiologists may need to administer significantly higher doses, often up to 1.5 to 2.0 mg/kg, to achieve adequate intubating conditions for rapid sequence intubation (RSI).
Unpredictable Response: The individual response can vary widely and is less predictable than in a healthy person. The higher dose, especially if repeated, can potentially lead to a dose-dependent phase II block, where the initial depolarizing block transitions into a nondepolarizing-like block with a prolonged duration.
Duration of Action: While typically short-acting in healthy individuals, the duration of succinylcholine's effect can be prolonged in MG patients, complicating extubation and postoperative recovery.
Potential for Myasthenic Crisis: Surgical stress and certain medications can precipitate a myasthenic crisis, a life-threatening complication involving respiratory failure. The unpredictable effects of NMBAs, including succinylcholine, increase the risk of residual weakness post-surgery.

Preferable Alternatives for Neuromuscular Blockade

Given the risks and uncertainties associated with succinylcholine, many experts recommend alternative approaches for managing neuromuscular blockade in MG patients. The use of a nondepolarizing agent with careful monitoring and a modern reversal strategy has become a standard of care.

Rocuronium with Sugammadex: This combination is often preferred. Rocuronium, a nondepolarizing agent, is administered at a significantly reduced dose (e.g., 0.5-0.6 mg/kg instead of the standard 1-1.2 mg/kg) due to the patient's heightened sensitivity. The effects are closely monitored using a peripheral nerve stimulator. The key advantage is the availability of sugammadex, a rapid and effective reversal agent that encapsulates rocuronium, essentially turning off its paralytic effect. This allows for a more controlled and predictable recovery of muscle function.
Avoiding NMBAs When Possible: In some cases, particularly for shorter procedures or when bulbar symptoms are mild, anesthesiologists may opt to avoid NMBAs entirely and rely on inhalational or intravenous anesthetic agents that provide sufficient muscle relaxation.

Comparison of NMBAs in Myasthenia Gravis


Agent Type	Example	MG Response	Dosing Consideration	Reversal Strategy	Primary Concern
Depolarizing	Succinylcholine	Resistant; requires higher dose.	Higher doses (1.5-2.0 mg/kg) are necessary for effective paralysis.	Spontaneous recovery, potentially prolonged; no specific reversal agent.	Unpredictable duration, risk of prolonged phase II block with repeat doses.
Nondepolarizing	Rocuronium, Vecuronium	Sensitive; requires significantly lower dose.	Lower, incremental doses are essential (e.g., reduced rocuronium to 0.5-0.6 mg/kg).	Sugammadex (for rocuronium/vecuronium) offers rapid, reliable reversal.	Heightened sensitivity can lead to profound and prolonged block if not carefully dosed.

Managing Crisis Situations: Myasthenic vs. Cholinergic

In the perioperative setting, MG patients can face two distinct types of crises, and their differentiation is critical for correct treatment. A myasthenic crisis is an exacerbation of the underlying disease due to surgical stress, infection, or other triggers, characterized by severe muscle weakness and potential respiratory failure. A cholinergic crisis, on the other hand, is caused by an overdose of anticholinesterase medications (like pyridostigmine), which leads to excessive acetylcholine stimulation and subsequent muscle weakness. For this reason, myasthenic patients should generally continue their anticholinesterase medications until the morning of surgery to prevent pre-operative weakness. While a myasthenic crisis warrants treatment like intravenous immunoglobulin (IVIg) or plasmapheresis, a cholinergic crisis requires the discontinuation of anticholinesterase medication and potentially atropine for muscarinic symptoms. Anesthesiologists must be vigilant in monitoring for these conditions, especially in the postoperative period.

Conclusion: Informed Choices for Patient Safety

While it is technically possible to use succinylcholine with myasthenia gravis, the unique pharmacologic profile of MG—specifically resistance to succinylcholine and sensitivity to nondepolarizing agents—makes its use less favorable. The potential for an unpredictable or prolonged response with succinylcholine, combined with the availability of safer alternatives like low-dose rocuronium with sugammadex reversal, has shifted clinical practice. Ultimately, the management of neuromuscular blockade in MG patients requires a nuanced understanding of the disease, meticulous monitoring, and a carefully considered strategy tailored to the individual, ensuring the safest possible outcome. Healthcare professionals and patients should be aware of these anesthetic considerations for optimal perioperative care, as highlighted by numerous anesthetic guidelines, such as those from the OpenAnesthesia resource.

Frequently Asked Questions

Patients with myasthenia gravis (MG) have an autoimmune attack on their postsynaptic acetylcholine receptors (AChRs) at the neuromuscular junction, which reduces the total number of receptors. Succinylcholine, a depolarizing agent, requires sufficient AChRs to bind and cause depolarization. With fewer receptors, a higher dose is needed to achieve effective paralysis.

Yes, while not associated with the same risk of hyperkalemia as in some other neuromuscular diseases, succinylcholine use in MG is risky. It requires a higher, less predictable dose, and repeated administration can cause a prolonged Phase II neuromuscular block.

The preferred alternative is a non-depolarizing neuromuscular blocker like rocuronium, used in conjunction with its specific reversal agent, sugammadex. The MG patient's hypersensitivity to rocuronium means a much smaller dose is required, and sugammadex allows for rapid and reliable reversal of the blockade.

Anesthesiologists administer nondepolarizing agents in reduced, incremental doses and carefully monitor the patient's neuromuscular function with a nerve stimulator. The availability of sugammadex provides a critical safety net, allowing for complete and rapid reversal when needed.

A myasthenic crisis is a severe, life-threatening exacerbation of the disease itself, causing profound muscle weakness and respiratory failure. A cholinergic crisis is a medication-induced complication resulting from an overdose of anticholinesterase inhibitors (MG medications), which overstimulates the NMJ and causes muscle weakness.

Yes, general anesthesia can be safely used in MG patients, but with specific precautions. Anesthesiologists often use short-acting agents, minimize or avoid opioids and benzodiazepines due to respiratory depressant effects, and use NMBAs with great caution, preferring a rocuronium-sugammadex strategy if a paralytic is needed.

For anticholinesterase medications like pyridostigmine, the patient should continue their regular dose through the morning of surgery to prevent preoperative weakness, but excess dosages must be avoided to prevent a cholinergic crisis. Patients should discuss their medication schedule with their care team well before the procedure.