over-the-counter vs nonprescription

over-the-counter and nonprescription both are adjectives.

Word	Noun	Adjective	Verb	Adverb
over-the-counter	No	Yes	No	No
nonprescription	No	Yes	No	No

As adjectives, over-the-counter and nonprescription are synonyms defined as:

over-the-counter and nonprescription: purchasable without a doctor's prescription

over-the-counter (adjective)	nonprescription (adjective)
purchasable without a doctor's prescription	purchasable without a doctor's prescription
(of securities) not traded on a stock exchange