truth drug vs Pentothal

truth drug and Pentothal both are nouns.

Word	Noun	Adjective	Verb	Adverb
truth drug	Yes	No	No	No
Pentothal	Yes	No	No	No

As nouns, Pentothal is a hyponym of truth drug; that is, Pentothal is a word with a more specific, narrower meaning than truth drug:

truth drug: an intravenous anesthetic drug that has a hypnotic effect; induces relaxation and weakens inhibitions; is believed to induce people to talk freely
Pentothal: barbiturate that is a hygroscopic powder (trade name Pentothal) that is a strong barbiturate that acts rapidly; induces a relaxed state when injected as a general anesthetic

Other hyponyms of truth drug include amobarbital, thiopental, thiopental sodium, thiopentobarbital sodium.

truth drug (noun)	Pentothal (noun)
an intravenous anesthetic drug that has a hypnotic effect; induces relaxation and weakens inhibitions; is believed to induce people to talk freely	barbiturate that is a hygroscopic powder (trade name Pentothal) that is a strong barbiturate that acts rapidly; induces a relaxed state when injected as a general anesthetic