drug
Meaning of drug: One word doing two jobs, respectable and illicit, which is why regulators and clinicians often reach for medicine or medication instead.
Definition of drug
A drug is any substance other than food that changes how the body works, whether taken to prevent, diagnose or treat disease or taken for its effect on mood and perception. The word covers prescription and pharmacy medicines, substances used in imaging and testing, and substances that are misused, and only context separates the senses.
What are the categories?
| Category | What defines it |
|---|---|
| Prescription | Requires an order from a licensed prescriber |
| Over the counter | Sold directly, judged safe enough for use without supervision |
| Controlled | Legal but restricted, because of misuse or dependence potential |
| Investigational | Under study, not yet approved for general use |
| Diagnostic | Given to make a test work, such as a contrast agent or a tracer |
These are legal and regulatory categories rather than chemical ones, and a substance can move between them. Something sold only on prescription in one country may sit on a pharmacy shelf as an over-the-counter product in another, and a medicine can be reclassified once enough is known about it.
How does a drug differ from a medicine or a medication?
Medicine and medication both imply a therapeutic purpose. Drug does not: it is the broader word and takes in substances used for their effect on mood, whether legal or not. That double meaning is why a hospital record asks for a drug history while a package leaflet refers to a medicine, and why regulators write medicinal product for what is prescribed. Pharmacologically the distinction does not exist, since a substance acts on the body in the same way regardless of the reason it was taken.
What do generic and brand name mean?
Every drug has a generic name identifying the active substance, agreed internationally and written in lower case. A brand name is owned by a company and written with a capital, and the same substance may carry a dozen brand names across different countries and manufacturers. Confusing the two is a common source of error, because a person can take two products believing them to be different medicines when both contain the same active ingredient. Approval, labeling and post-marketing surveillance sit with a national regulator such as the Food and Drug Administration, which decides what a product may claim and how it must be described.
Used in a sentence
The intake form asked the patient to list any prescription drug taken regularly.
Good to know
The word drug can refer to a prescribed medicine or to a substance associated with dependence and misuse, so its intended meaning is generally clarified by context rather than by the word alone.