pɹəˈskɹɪpʃən pɹəˈskɹɪpʃən available only with a doctor's written prescription a prescription drug 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 written instructions from a physician or dentist to a druggist concerning the form and dosage of a drug to be issued to a given patient written instructions for an optician on the lenses for a given person directions prescribed beforehand; the action of prescribing authoritative rules or directions I tried to follow her prescription for success