What is Pharmacology and the Veterinary Drug (Pharmacon)? Definitions
The simplest known definition of pharmacology is:
“Pharmacology is the science that studies the effects of substances on organisms.”
However, this definition is too general and, as such, unsatisfactory.
Pharmacology (pharmakon = drug; logos = science) is the science that deals with the study of drugs in terms of their origin, physical and chemical structure, composition, kinetics, and action in the body, as well as their use in the treatment of various animal diseases.
Pharmacology can also be defined as: the study of the action of pharmacons on living organisms.
Pharmacons
These are chemical substances that can alter the functions of living organisms. The WHO defines the term pharmacon (which corresponds to the English term drug in its meaning):
“A drug is any substance or product that is used or intended to be used to modify or explore physiological systems or pathological states for the benefit of the recipient.”
A pharmacon is any substance or product used or proposed for use to influence or investigate physiological systems or pathological states for the benefit of the patient.
Pharmacology is best characterized by the questions: Where, how, and why does a substance act, and what is being investigated?
A drug can also be defined as follows:
“A drug is a biologically active substance or a combination of substances which, according to medical science research, when administered rationally to humans or animals, can enable:
a) the recognition, removal, alleviation, or prevention of the symptoms of a disease;
b) the recognition of or influence on organic structures, organic functions, or the behavioral typology of humans or animals, as long as this serves medical purposes.”
An ideal drug should have:
- Precise activity,
- A known mechanism of action,
- Consistent efficacy,
- Absence of adverse effects, and
- Economic accessibility.
Finally, a drug is:
a pharmaceutical preparation resulting from the incorporation of an exact measured amount of one or more active substances into a formulation that allows for preventive or curative administration.
As can be seen, there is still no universally accepted definition.
Veterinary Drug (Ad usum veterinarum)
A veterinary drug is also defined as:
a substance or a mixture of chemical substances of plant or animal origin, intended to fight diseases, strengthen health, and restore unbalanced physiological functions.
In this context, the definition of a biological product is also required:
a preparation of bacterial, fungal, human, plant, or animal origin intended for the prevention of diseases or the establishment of a diagnosis.
To prevent the use of unverified drugs, the Veterinary Health Law stipulates that only drugs and biological products included in the Nomenclature of Veterinary Medicines and Biological Products may be used (including imported products, which can only be used after being included in this list).
The marketing of unauthorized or unregistered biological products, drugs, or medical equipment is prohibited and punishable by law.
In addition to the notion of “drug,” other terms may be encountered:
- Galenic form,
- Preparation,
- Medicinal form,
- Pharmaceutical form,
- Pharmaceutical product,
- Remedy (general term).
Pharmaceutical Substances
In the sense of the pharmacopoeia, these are raw materials or drugs of animal, plant, or mineral origin, extracted or synthesized, which must meet certain purity or content conditions specified in the pharmacopoeia.
Their transformation into drugs is done through appropriate operations.
The sources from which drugs can be obtained are: plant, animal, mineral, and synthetic, and are generically known as drugs [1].
Toxic is understood as:
“any substance which, when introduced into the body, causes general disorders known as intoxication.”
There is a close relationship between food, drugs, and toxins.
For example, many substances that are part of ordinary foods (e.g., glucose, vitamins, mineral salts, trace elements, etc.) are also used as drugs in deficiency states.
A series of medicinal substances (antibiotics, chemotherapeutics, etc., especially those used for antibacterial therapy) can also be used as feed additives to increase weight gain in young animals.
All drugs that are absorbed into the body are toxic, generally at doses higher than therapeutic ones.
Long before modern pharmacology emerged, Paracelsus (1493–1541) stated that all substances are potentially “poisons” and that it is only the dose that makes the poison — “Dosis sola facit venenum.”
[1] This does not correspond to the English term “drug” (i.e., medicine), but refers to (dried) parts of plants or animal organs that contain active substances and are used therapeutically as they are or after further processing.
Plant drugs are numerous and may consist of leaves, bark, roots, flowers, or dried sap and are used as teas, extracts, powders, etc.
Animal-derived drugs are less common in European therapeutic science but much more common in traditional Asian medicine (e.g., dried thyroid gland (Glandula thyreoidea siccata), dried ox bile (Fel tauris siccata), etc.), and are used almost exclusively in homeopathic medicine.