Table 1  Drugs which may worsen myasthenia gravis (data from 11 ).

Types	Substances
* Clinically relevant worsening of disease is rare if the dose is increased slowly or medium doses are primarily administered.
Analgesics	flupirtine, morphine preparations
Antiarrhythmics	quinidine, ajmaline, mexitilene, procainamide
Antibiotics	aminoglycosides (particularly streptomycin, neomycin, less so tobramycin), macrolides (e.g., erythromycin), ketolides (telithromycin/Ketek), lincomycin, polymyxins, gyrase inhibitors (levofloxacin, ciprofloxacin, prulifloxacin), sulfonamides; tetracyclines, penicillin only in very high doses
Antidepressants	amitriptyline-type substances
Anticonvulsants	benzodiazepines, carbamazepine, diphenylhydantoin, ethosuximide, gabapentin
Antimalarial drugs	quinine, chloroquine and analogs
Antirheumatic agents	D-penicillamine, chloroquine, etanercept
β-blockers	oxprenolol, pindolol, practolol, propranolol, timolol – also as a topical application in the form of eye drops
Botulinum toxin
Calcium antagonists	verapamil, diltiazem, nifedipine and related analogs
Diuretics	azetazolamide, benzothiadiazines, loop diuretics
Glucocorticoids*	transient worsening if high doses are used at the start of treatment
Interferons	interferon α (selected cases)
Lithium
Local anesthetics	procaine (ester type), the amides used nowadays are unproblematic
Magnesium	high doses as laxatives
Muscle relaxants	curare derivatives, the initial dose should be 10 – 50% of the normal dose because of the increased sensitivity succinylcholine should not be used as it cannot be antagonized with pyridostigmine
Psychotropic drugs	chlorpromazine, promazine and related drugs, all benzodiazepines and structural analogs such as zolpidem, zopiclone
Statins	several reports of different cholesterol-lowering drugs
This list is not complete. When any new medication is introduced, the patient must be informed about the possibility of a further deterioration of MG and must be asked about typical symptoms and their intensity. But it is also important to take account of times when a life-threatening disease requires a specific drug.