Pharmacology is the study of the action of drugs on a biologic system. It incorporates components of medicine and biology, and how they interact with each other.
Drugs can refer to many different substances, and are defined as any substance (man-made, naturally occurring or endogenous molecules) that exerts an effect on a cell, tissue, or organ within the body.
Pharmacology deals with the origin of drugs, their characteristics, and their effects, such as biologic, chemical or therapeutic, on a living system.
Pharmacology is distinct from pharmacy. Pharmacology refers to the science of the discovery and characterization of substances that have an effect on the body.
On the other hand, pharmacy refers to the health services that use the concepts of pharmacology to improve health outcomes in a clinical setting.
Medical pharmacology laboratory. Image Copyright: Zarya Maxim Alexandrovich / Shutterstock
Traditionally, the actions of pharmaceutical substances – usually from natural sources or plant extracts, such as morphine and quinine – were poorly understood and explained in general terms, without deep knowledge of their actions on the body.
Clinical pharmacology dates back to the Middle Ages, and William Withering (1741-1799) was one of the primary founders of this field of study. However, it was not until halfway through the 19th century that it progressed further as a scientific discipline. This was largely due to the advancements in biomedical science at that time.
Throughout the 19th and 20th century, the field of pharmacology as a biological science continued to develop and its discoveries began to be applied in a therapeutic setting.
Today, pharmacologists use a variety of techniques, including genetics, molecular biology and chemistry, to explain and manipulate the pharmacological action of substances for health purposes. This has helped to bring about great advances in the field of medicine over the past century.
It has brought in a deeper understanding of how medications can be effectively used to manage various health conditions and diseases.
Pharmacology is a broad field, and its study includes a number of different topics. These include:
- Drug composition
- Drug properties
- Drug synthesis and disease
- Molecular and cellular mechanisms of drug action
- Organ and body system mechanisms
- Signal transduction and other cellular communication
- Molecular diagnostics
- Drug interactions
- Chemical biology
- Drug therapy
- Medical applications
Pharmacodynamics and Pharmacokinetics
Pharmacodynamics and pharmacokinetics are the two principal areas of pharmacology. Pharmacodynamics focuses on the effect that a drug can exert on the biology of the body. Pharmacokinetics focuses rather on how the body affects the drug, in terms of its absorption, metabolism, distribution and elimination.
Pharmacodynamics is based on studying how pharmaceutical substances affect the receptors in the body, and on how these effects can be beneficial for certain purposes.
Pharmacokinetics studies how the body reacts when pharmaceutical substances are introduced into the bodily systems. This is split up into four main topics: absorption of the drug, distribution around the body, metabolism into other substances and excretion from the body (referred to as ADME).
There are many different sub-disciplines or specializations under the umbrella of pharmacology. These include:
- Cardiovascular pharmacology: the effects of pharmaceuticals on the cardiovascular system
- Clinical pharmacology: the clinical applications of pharmaceuticals
- Dental pharmacology: the use of pharmaceuticals in dental disease
- Environmental pharmacology: understanding the interaction between genes, the environment and pharmaceuticals
- Neuropharmacology: the effects of pharmaceuticals on the central and peripheral nervous system
- Pharmacoepidemiology: the effects of pharmaceuticals observed in large population groups
- Pharmacogenetics: the relationship between genetic variability and drug response
- Pharmacogenomics: the use of genomic technologies to discover and characterize pharmaceuticals
- Pharmacognosy: the composition, use and development of pharmaceuticals
- Posology: the science of arriving at the correct dosing of pharmaceuticals
- Psychopharmacology: the behavioral changes associated with pharmaceuticals, or the use of pharmaceuticals to bring about behavioral modifications
- Systems pharmacology: the application of the biologic principles of a system to manipulate pharmaceuticals
- Theoretical pharmacology: the theory underlying the effect of new pharmaceuticals
- Toxicology: the adverse effects of pharmaceuticals
A pharmacologist may specialize in any one of these sub-disciplines to conduct deeper research into a specific area of pharmacology.
Reviewed by Dr Liji Thomas, MD.