(FDA approved in bold)

• Lambert-Eaton myasthenic syndrome (LEMS)
  
• Congenital myasthenia gravis (CMG)
  
• Multiple sclerosis (MS)

• Potassium channel blocker. Reduces flow of potassium across nerve terminal membranes and increases calcium influx with prolongation of action potential. This promotes presynaptic release of acetylcholine and may improve weakness and autonomic dysfunction

• About 20 minutes, but maximum effect might take a few days

• Continue to use to reduce symptoms of LEMS or CMG at lowest required dose. In LEMS, disease-modifying treatments, such as plasma exchange, intravenous immune globulin, corticosteroids, or immunosuppressives, are useful
  
• Identifying malignancy such as small-cell lung cancer is essential

• LEMS – Treat with immunologic therapy. Removal of neoplasm may improve symptoms
  
• CMG – Establish the type. Presynaptic forms may respond to 3, 4 diaminopyridine. Acetylcholinesterase inhibitors may improve or worsen symptoms, depending on the disorder

• May be combined with pyridostigmine, which increases the available amount of acetylcholine for receptor binding and may allow reduction of dose

• Obtain baseline CBC, electrolytes, glucose, BUN, creatinine, liver function tests. Repeat monthly for 3 months, then every 6 months while on treatment