Pharmacology

Pharmacology is the science that describes the interactions between drugs and organisms.
Two aspects of this interaction, pharmacodynamics and pharmacokinetics, are of particular importance.
Pharmacodynamics is concerned with the effects of a drug on the body: how the substance acts, with what side effects, on which tissues, on which receptor sites, at what concentration, etc.
The effects of drugs can be affected by other drugs as well as by many factors, including medical conditions. Pharmacodynamics also attempts to describe the phenomena of antagonism, synergism, additive effects and other phenomena. Pharmacokinetics, on the other hand, deals with the body's effects on the substance, through absorption, distribution, metabolism and excretion.

Clinical Pharmacology

Clinical Pharmacology is the scientific discipline that involves all aspects of the relationship between drugs and humans.
Its breadth includes the discovery and development of new drugs, the application of drugs as therapeutic agents, the use of drugs, the beneficial and harmful effects of drugs in individuals and society, and the deliberate misuse of drugs.
Clinical pharmacology is a multidisciplinary team science that encompasses professionals with a wide variety of scientific skills including medicine, pharmacology, pharmacy, biomedical science and nursing.
Other professionals who are important in various aspects of clinical pharmacology include social and behavioural scientists, dentists, economists, epidemiologists, geneticists, toxicologists, mathematicians and computer scientists.

The World Health Organization defines clinical pharmacology as the set of activities relating to the fate and effects of drugs in humans and their use:
1° study of responses to the administration of substances: pharmacokinetics and human pharmacodynamics (phases I, II).
2° evaluation of the efficacy of drugs: clinical trials (phases II, III).
3° study of the fate of molecules in the body: pharmacokinetics.
4° detection, evaluation, understanding and prevention of the risks of adverse drug reactions: pharmacovigilance.
5° detection, evaluation, monitoring of the addictive potential of drugs and licit substances: drug dependence.
6° evaluation of the medico-economic consequences attributable to the use of a drug by analyzing the cost / effectiveness, cost / utility ratios of the drug before and after A.M.M .: pharmacoeconomics.
7° characterization of the use of drugs in different populations or social groups: pharmacoepidemiology.
8° variation of the effects or kinetics of drugs depending on the genetic characteristics of the individual: pharmacogenetics.
9° multidirectional interactions between the drug, the partners involved from its discovery to its final use and society: social pharmacology.
10° advice on the individual methods of use of the drug: prescription assistance and information on the drug.
Drugs are chemicals that exert an effect (pharmacodynamics) through their interaction (s) on one or more biological systems of varying complexity.
A drug acts on a cell target (membrane receptor, channel, enzyme, transporter, etc.) either directly or through an effector system (this is called signaling).
The location of both the target (s) and the type of effector determine the response elicited by the interaction of the drug with its biological target.
For each individual, this response is modulated by a large number of parameters:
drug concentrations at its sites of action,
the presence of possible products of its biotransformation (metabolites) when they have pharmacodynamic activity (identical or different from the parent product from which they were formed)
the specific "sensitivity" of the individual receiving the drug:
- number of targets present
- level of coupling between the target and a possible effector
- genetic factors (determining, for example, the activity of enzymes responsible for the biotransformation of the parent product or the number of target receptors)
- pathological factors (renal, hepatic, cardiac insufficiency, nutritional state, ...)
- physiological factors (pregnancy, aging, body mass, ...)
- environmental factors (pollutants, temperature, time of day, nutrition, ...)
external factors: interactions between several drugs or with food.
such that there is often (but not always) a large variability in the individual response to administration of a standard dose of drug.
An individual's response to the administration of a drug consists of desired effects (corresponding to a therapeutic goal) and undesired effects (adverse effects that are more or less predictable).