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medication (also referred to as medicinepharmaceutical drug, or simply drug) is a drug used to diagnosecuretreat, or prevent disease.

Drug therapy (pharmacotherapy) is an important part of the medical field and relies on the science of pharmacology for continual advancement and on pharmacy for appropriate management.

The practice of medicine in the early Middle Ages was empirical and pragmatic.

It focused mainly on curing disease rather than discovering the cause of diseases.

Drugs are classified in multiple ways.

One of the key divisions is by level of drug control, which distinguishes prescription drugs (those that a pharmacist dispenses only on the order of a physicianphysician assistant, or qualified nurse) from over-the-counter drugs (those that consumers can order for themselves).

Another key distinction is between traditional small-molecule drugs, usually derived from chemical synthesis, and biopharmaceuticals, which include recombinant proteinsvaccinesblood products used therapeutically (such as IVIG), gene therapymonoclonal antibodies and cell therapy (for instance, stem-cell therapies).

Other ways to classify medicines are by mode of action, route of administrationbiological system affected, or therapeutic effects. An elaborate and widely used classification system is the Anatomical Therapeutic Chemical Classification System (ATC system).

The World Health Organization keeps a list of essential medicines.

Essential medicines, as defined by the World Health Organization (WHO), are the medicines that “satisfy the priority health care needs of the population”.[1] These are the medications to which people should have access at all times in sufficient amounts.


In Europe, the term is “medicinal product”, and it is defined by EU law as:

  • “Any substance or combination of substances presented as having properties for treating or preventing disease in human beings; or”
  • “Any substance or combination which may be administered to humans either with a view to restoring, correcting or modifying physiological functions by exerting a pharmacologicalimmunological or metabolic action.