The Collaborative International Dictionary
Contrastimulant
Contrastimulant \Con`tra*stim"u*lant\, a. Counteracting the effects of stimulants; relating to a course of medical treatment based on a theory of contrastimulants. -- n. (Med.) An agent which counteracts the effect of a stimulant.
Wiktionary
contrastimulant
n. (context medicine English) Any agent that counteracts the effect of a stimulant.