Medications to Avoid in Myasthenia Gravis

High-Risk Medications to Avoid

Patients with myasthenia gravis should avoid beta-blockers, IV magnesium, fluoroquinolones, aminoglycosides, and macrolide antibiotics as these medications can worsen myasthenic symptoms and potentially precipitate a myasthenic crisis 1, 2, 3
Aminoglycosides can block neuromuscular transmission and precipitate weakness 3
Fluoroquinolones can worsen neuromuscular blockade 3
Beta-blockers can worsen neuromuscular weakness 3
IV magnesium can impair neuromuscular transmission 3

Depolarizing agents, such as suxamethonium, are contraindicated in myasthenia gravis due to risk of prolonged effect 4
Non-depolarizing agents require 50-75% reduction in dosing in patients with myasthenia gravis 4
Sugammadex is recommended for reversal of steroidal muscle relaxants in MG patients when necessary 4
Neostigmine may interfere with long-term MG treatment and should be used with caution 4

If patients with myasthenia gravis are receiving immune checkpoint inhibitor therapy for cancer treatment, special monitoring is required as these agents can exacerbate MG 5, 6
For grade 2 symptoms, hold immune checkpoint inhibitors 3
For grade 3-4 symptoms, permanently discontinue immune checkpoint inhibitors 3

For infections requiring antibiotics, consider consultation with neurology for antibiotic selection when treatment is necessary 3

Topical bacitracin appears to be safe for use in myasthenia gravis patients based on ophthalmic guidelines 7, 8
The American Academy of Ophthalmology recommends topical bacitracin as a safer option for patients with myasthenia gravis 7, 8

For patients with renal impairment, the National Kidney Foundation recommends macrolides require a 50% dose reduction when GFR < 30 ml/min/1.73 m² 9
The National Kidney Foundation also recommends tetracyclines should be reduced in dose when GFR < 45 ml/min/1.73 m² as they can exacerbate uremia 9

Fluoroquinolones (ciprofloxacin, levofloxacin, moxifloxacin) worsen neuromuscular blockade and should be avoided in patients with myasthenia gravis, according to the American College of Physicians, as they can precipitate myasthenic crisis and respiratory failure 10

Atracurium and mivacurium should be avoided in patients with myasthenia gravis, while rocuronium and vecuronium are safer alternatives, as recommended by the National Comprehensive Cancer Network 11
Propofol, sevoflurane, isoflurane, fentanyl, remifentanil, lidocaine, and bupivacaine are considered safer anesthetic options for patients with myasthenia gravis, according to the National Comprehensive Cancer Network 11

For patients receiving cancer immunotherapy, immune checkpoint inhibitors can trigger or exacerbate myasthenia gravis, and specific management protocols are required, including holding or permanently discontinuing immune checkpoint inhibitors, and initiating methylprednisolone 2 mg/kg IV for severe symptoms, as recommended by the European Society for Medical Oncology 10
Consider plasmapheresis or IVIG if no improvement or worsening occurs in patients with myasthenia gravis receiving immune checkpoint inhibitors, according to the European Society for Medical Oncology 10

Monitor for worsening muscle weakness, particularly proximal limb and ocular muscles, and assess respiratory function with vital capacity and negative inspiratory force when potentially problematic medications must be used in patients with myasthenia gravis, as recommended by the American Academy of Neurology 10
Watch for bulbar symptoms (speech, swallowing difficulties), diplopia, and ptosis in patients with myasthenia gravis receiving potentially problematic medications, according to the American Academy of Neurology 10

Aminoglycosides, such as streptomycin, gentamicin, tobramycin, neomycin, kanamycin, and amikacin, are absolutely contraindicated in myasthenia gravis patients due to their potential to precipitate life-threatening myasthenic crisis and respiratory failure, as recommended by the European Respiratory Society 12, 13
Streptomycin is explicitly contraindicated in myasthenia gravis due to its neuromuscular blocking properties and ability to potentiate weakness, as reported by the European Respiratory Journal 12, 13
All aminoglycosides act as neuromuscular blocking agents by reducing presynaptic calcium uptake and acetylcholine release, according to the Centers for Disease Control and Prevention 14
Neuromuscular blocking potency is highest with neomycin, followed sequentially by gentamicin, streptomycin, kanamycin, amikacin, and tobramycin, as stated by the Centers for Disease Control and Prevention 14

Tetracyclines should only be used after careful consideration and with appropriate monitoring, due to theoretical concerns regarding tetracycline chelation of calcium, which could worsen neuromuscular transmission, as recommended by the Centers for Disease Control and Prevention 14
Clindamycin should only be administered after careful consideration and with appropriate monitoring, due to concerns about its ability to block acetylcholine release, potentially working synergistically with aminoglycosides, as stated by the Centers for Disease Control and Prevention 14

When potentially problematic antibiotics must be used, patients should be monitored for clinical deterioration that could be related to the antibiotic, as recommended by the Centers for Disease Control and Prevention 14