By reading this chapter, you will:
- Become familiar with the pharmacological vocabulary
Pharmacology studies drugs and their interactions with living organisms. In a broad sense, a drug is any substance that induces functional changes in an organism through a chemical or physical action, regardless of whether the resulting effect is beneficial or detrimental to the health of the receiving organism. In a more strict medical sense, a drug is a substance used in the diagnosis, treatment, or prevention of diseases or as a component of a medication.
Thus, the fields of interest in pharmacology are multiple, including chemistry, molecular and cellular biology, pathology, clinic, and toxicology. Studying a drug may mean investigating the chemical properties underlying its biological activity, or the way to synthesize or extract it, or its effects on cells, tissues, and organs or on healthy and diseased human subjects. Pharmacology bridges basic and clinical research, as it provides tools for a rational therapy of known pathologies as well as empirical approaches for diagnosis and cure of obscure diseases (cure ex adjuvantibus).
As Leonardo da Vinci said, “The medical doctor will use drugs in an appropriate way when he knows what a human being is, what life and complexion are and what health is.” In this sense, a pharmacologist is a physiologist, as she/he deals with substances and methods that modify physiological functions. However, she/he is also a pathologist capable of understanding chemical and molecular causes of pathologies, a biochemist and a molecular and cellular biologist using tools and methods of these disciplines to test drugs or vice versa employing drugs to investigate cellular and molecular processes, and a clinician using drugs to cure patients.
THE SOCIAL IMPACT OF PHARMACOLOGY
Using drugs to treat diseases and conditions has changed the life of humanity (see Chapter 2). Several factors have contributed to the remarkable improvements in population health that have occurred over the last century in developed countries: improved hygienic conditions, more widespread culture of prevention and health, richer and more balanced diet, and less physically wearing working conditions. However, such effects on life quality and duration would not have been so significant without the development of drugs and evidence-based approaches to human health care.
Drugs have contributed to the disappearance of many serious diseases. As an example, consider the number of daily deaths from bacterial pneumonia during winter months in general hospitals before World War II as compared to the almost total absence of this disease in current death records. Drugs have also reduced hospitalization, lowered incidence and gravity of several disease-induced permanent damages, and allowed to manage many serious and degenerative diseases. The most striking example of the role played by drugs in the control of serious diseases is the case of acquired immune deficiency syndrome (AIDS): in just a few years, specific antiviral drugs have turned the disease from “plague of the century” to a chronic illness compatible with an almost normal life. Pharmacology has also had an impact on surgery, as, for example, H2 histamine receptor antagonists and proton pump inhibitors have almost eliminated gastric and duodenal ulcers and the need for surgical gastrectomy and antibiotics have significantly reduced the number of appendectomies.
Drug success has been so impressive to induce part of the lay public to believe that there could be a “pill” for every disease or any uncomfortable symptom, causing an excessive “medicalization” of society and often the inability of people to accept that not all diseases are treatable and not all patients can be cured. Unfortunately, when such huge expectation on medicine collides with a failure, it may lead to a general distrust and irrational refusal of medical treatments pushing people toward the so-called alternative medicines. Based on the ethical principle that drug usage must be supported by scientific demonstrations of its effectiveness in patients, pharmacology has created strict rules that preclinical and clinical drug investigations (see Chapters 54, 55, and 56) have to comply with before drugs can be approved for clinical use. These rules are rigorously applied in drug development and use but are often ignored by producers and supporters of “alternative medicines.” This lack of severe preclinical and clinical experimentations implies that “alternative” products and procedures often have not undergone a careful evaluation of benefits (if any) and risks. In the best cases, the evidence supporting these practices is anecdotal, reported by minor scientific journals often lacking serious review procedures (see Supplement E 1.1, “Alternative or Nonconventional Therapies”).
Pharmacology has also a social impact. Consider, for example, drugs controlling fertility, emotions, and mental and physical performances or drugs affecting the individual’s perception of the external world or the social plague of drug addiction.
Pharmacological treatment of diseases is a duty for social health systems; it must be guaranteed to the population but it also has costs. This has important implications, both positive and negative, for the relationships between drug companies and public health systems. All these scientific, economic, ethical aspects make pharmacology a discipline with very broad and loosen borders in which technical aspects are associated with equally important ethical issues.