A prescription drug is a pharmaceutical drug that is permitted to be dispensed only to those with a medical prescription. In contrast, over-the-counter drugs can be obtained without a prescription. The reason for this difference in substance control is the potential scope of misuse, from drug abuse to practicing medicine without a license and without sufficient education. Different jurisdictions have different definitions of what constitutes a prescription drug.
Photo of the packaging of four medicines registered in the UK, showing their Product Licence Numbers and symbols denoting if they are Prescription Only Medicine (POM) or Pharmacy Medicine (P)
A prescription, often abbreviated ℞ or Rx, is a formal communication from a physician or other registered healthcare professional to a pharmacist, authorizing them to dispense a specific prescription drug for a specific patient. Historically, it was a physician's instruction to an apothecary listing the materials to be compounded into a treatment—the symbol ℞ comes from the first word of a medieval prescription, Latin recipere, that gave the list of the materials to be compounded.
The prescription symbol, ℞, as printed on the blister pack of a prescription drug