Drugs that may impair neuromuscular transmission
Agents contraindicated in myasthenic crisis:
These agents may be administered with caution in stable MG patients.
- Acetazolamide
- Antispasmodics (e.g. Propantheline, Oxybutinin, Atropine)
- Ampicillin (may cause respiratory depression according to few reports)
- Azithromycin
- Beta blockers
- Benzodiazepines
- Clorpromazine
- Chloroquine
- Clarithromycin
- Ecothiophate
- Erythromycin
- Fluoroquinolones
- Inhalation anaesthetics
- Imipenem
- Levonorgestrol implant
- Lithium
- Opioid narcotics
- Phenytoin
- Pyrantel
- Proparacaine/tropicamide
- Quinine
- Ritonavir
- Statins
- Sulfonamides
- Tetracyclines
- Transdermal nicotine patch
- Verapamil
Agents contraindicated even in stable MG patients:
- Aminoglycosides
- Bacitracin and Polymixin (systemic use)
- Botulinum toxin
- Colistin
- Clindamycin
- Ionic contrast agents
- Lignocaine and possibly other class I antiarrythmics
- Lincomycin
- Magnesium containing preparations, IV use
- Neuromuscular blocking drugs
- Procainamide
- Quinidine
- Telithromycin
Other agents that have been known to precipitate myasthenic crisis
(Insufficient evidence on usage in stable MG patients. Assess risk/benefit and use with caution.)
- Calcium antagonists (verapamil, nifedipine, felodipine)
- Gabapentin
- Methimazole
- Interferon α
- Corticosteroids
The incidence of myasthenic crisis resulting from corticosteroids is 9-18%. Starting corticosteroid treatment for MG should always occur in a hospital with proper respiratory function monitoring.
References
- Myasthenic crisis. QJM . 2009; 102:97-107. doi: 10.1093/qjmed/hcn152
- Myasthenia gravis. Lancet . 2001;357:2122-2128. doi: 10.1016/S0140-6736(00)05186-2
- Drugs that may trigger or exacerbate myasthenia gravis Tidsskr Nor Laegeforen. 2013 Feb 5;133(3):296-9. doi: 10.4045/tidsskr.12.0624
- Drug-induced myasthenic syndromes Acta Neurol Scand Suppl. 1984:100:39-47