Drugs are pharmacological agents (a substance or mixture of substances) which have been clinically tested and authorized for use in the prevention, diagnosis and treatment of various diseases.
Drugs can be obtained from blood, blood plasma, human or animal tissue, plants, minerals, by synthesis method or by using biotechnology. Drugs possess pharmacological activity and are intended for the production and manufacture of pharmaceutical forms.
A wide range of medicines available on the pharmaceutical market gave occasion to create drugs classifications. The most widespread classifications include:
Currently ATC classification is the most widespread in clinical practice. ACT divides medicines into different groups according to the organ or system on which they act and/or their therapeutic and chemical characteristics. Each group depending on its level in classification has alphabetical or digital code. Generally each international nonpropriatory name has only one ATC code. Medicines which have several indication may have many ATC codes.
Anatomical Therapeutic Classification divides groups into three or four subgroups. This classification is actively used by Institute of Mathematical Statistics with a purpose to provide statistical results of market research for the needs of the pharmaceutical industry.
Nosological Classification divides drugs into 21 class depending on diseases of organs and systems. Nosological Classification helps search medications using their indications.
Pharmaceutical Classification divides drugs depending on their pharmacological group and pharmacological effect.
Medicines can also be classified in dependence of chemical structure, pharmacy purchasing terms Rx(prescriprtion) or OTC (over-the-counter) drugs.