Opposite words for prescription:
over-the-counter medicine, over-the-counter drug, over-the-counter, nonprescription.
Usage samples:
  1. He saw a good deal more in Deacon Ainsworth's house than the eyes of Jabez, which he had come to see, and his prescription went beyond them.
    "Eunice", Margaret Murray Robertson.
  2. Now, if you could make up a prescription which would give me back my powers of twenty years ago- Dr Trevor laughed, while Betty, Jack, and Jill mentally erected a monument, and placed the figure of the victim upon it in everlasting gratitude and affection.
    "Betty Trevor", Mrs. G. de Horne Vaizey.
  3. The other explanations, which make the sin to have been offering at an unauthorised time, or offering incense not compounded according to the prescription, give an unnatural meaning to the phrase.
    "Expositions of Holy Scripture Genesis, Exodus, Leviticus and Numbers", Alexander Maclaren.
  4. Nevertheless he was of a mind to clear the slate and get some sleep that night, and having taken his prescription and paid for it, he sat back and commenced an apparently casual interrogation.
    "The Breaking Point", Mary Roberts Rinehart.