For what reasons ephedrine (ephedrine sulfate) is given in myasthenia gravis?

see below: Ephedrine (ephedrine sulfate) appears to be an effective treatment for dok-7 cms. It is well-tolerated by most patients and improvement in strength can be profound. Determining the long-term response and the most effective dosing regimen will require further research.This is related to a special type of myasthenia gravis. Please see your doctor before beginning any therapy.