The Collaborative International Dictionary of English v.0.48:

Antispastic \An`ti*spas"tic\, a. [Gr. ?. See Antispast.]
   (Med.)
   (a) Believed to cause a revulsion of fluids or of humors from
       one part to another. [Obs.]
   (b) Counteracting spasms; antispasmodic. -- n. An antispastic
       agent.
       [1913 Webster]