Ritalin vs excitant

Ritalin and excitant both are nouns.

Word	Noun	Adjective	Verb	Adverb
Ritalin	Yes	No	No	No
excitant	Yes	Yes	No	No

As nouns, excitant is a hypernym of Ritalin; that is, excitant is a word with a broader meaning than Ritalin:

Ritalin: central nervous system stimulant (trade name Ritalin) used in the treatment of narcolepsy in adults and attention deficit disorder in children
excitant: a drug that temporarily quickens some vital process

Other hypernyms of Ritalin include stimulant, stimulant drug.

Ritalin (noun)	excitant (noun)
central nervous system stimulant (trade name Ritalin) used in the treatment of narcolepsy in adults and attention deficit disorder in children	a drug that temporarily quickens some vital process

Ritalin (adjective)	excitant (adjective)
	(of drugs e.g.) able to excite or stimulate