prescription medicine has 3 distinct synonyms spread across 1 of its 1 sense. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. Its one recorded opposite is over-the-counter medicine.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
a drug that is available only with written instructions from a doctor or dentist to a pharmacist
“he told the doctor that he had been taking his prescription regularly”
Synonyms, antonyms and the broader and narrower relations for prescription medicine come from Princeton University’s WordNet. Full sources and licences.