pentobarbital vs barbiturate

pentobarbital and barbiturate both are nouns.

Word	Noun	Adjective	Verb	Adverb
pentobarbital	Yes	No	No	No
barbiturate	Yes	No	No	No

As nouns, barbiturate is a hypernym of pentobarbital; that is, barbiturate is a word with a broader meaning than pentobarbital:

pentobarbital: a barbiturate (trade name Nembutal) used as a sedative and hypnotic and antispasmodic
barbiturate: organic compound having powerful soporific effect; overdose can be fatal

pentobarbital (noun)	barbiturate (noun)
a barbiturate (trade name Nembutal) used as a sedative and hypnotic and antispasmodic	organic compound having powerful soporific effect; overdose can be fatal