prescription

A prescription is a clinician's formal order authorizing a specific medicine for a specific patient. It is at once a set of instructions, a legal authorization, and a communication between prescriber, pharmacist, and patient. In short, it is the document that turns 'this patient should take this drug' into something a pharmacy can legally and safely act on.

A complete prescription specifies who, what, how much, and how: the patient's identity, the drug (ideally by generic name), the strength and dose, the route, the frequency, the duration or quantity, and any special instructions. It carries the prescriber's identification and signature. Each element exists to prevent error, because ambiguity in any field can lead to the wrong drug or dose reaching the patient.

Prescriptions also mark a legal boundary. Many drugs are 'prescription-only' precisely because they need professional judgment to use safely, in contrast to over-the-counter medicines. Writing a prescription is therefore an act of accountability: it commits the prescriber to having chosen an appropriate drug, dose, and regimen, and to having weighed the indication, contraindications, and interactions for that individual.