The word Pharmacology is derived from the Greek words Pharmakon, which means “an active principle” (drugs), and logos which means a study/knowledge.
DEFINITION
Pharmacology is a branch of science, which deals with the detailed study of effective and safe use of the drugs, for medicinal purposes [Particularly their action on living animals organs or tissues].
The action may be beneficial or harmful.
Pharmacology is an integrated rather than an autonomous science. The techniques and knowledge of several disciplines such as physiology, biochemistry, physics, chemistry and even mathematics have been incorporated to make the subject easier and well defined.
Practically Pharmacology deals with the knowledge about drugs, which includes their sources, chemical structure, dosage, form, route of administration, pharmacokinetics, pharmacodynamics, frequency of administration, indications (uses), contraindications, adverse effects and the drug interactions.
WHAT IS DRUG?
It is any substance that affects a biological system in a potentially useful way.
Drug: The word ‘drug’ is derived from a French word ‘Drogue’ – a dry herb. In general, a drug is defined as any substance (natural or synthetic) used for the purpose of diagnosis, prevention and relief or cure of any disease in men or animals.
In 1966, WHO has given a more comprehensive definition for drug: “Drug is any substance or product that is used or is intended to be used to modify or explore physiological systems or pathological status for the benefit of the recipients.”
A single drug does not fulfill all the purposes, for example, BaSO4 used for the diagnosis, Polio vaccine is used for prophylaxis of poliomyelitis, while metronidazole is commonly used for the treatment of amebiasis with the purpose to cure the disease.
SUBDIVISIONS OF PHARMACOLOGY
Pharmacokinetics: It is the scientific study of fate of the drug in the body including absorption, distribution, biotransformation, and excretion. In short it deals with “what the body does to the drug”.
Pharmacodynamics: It include the study of:
- Biological effects of the drug.
- Site and ‘mechanism of action’ of the drug.
- ‘Dose: response’ relationship.
In short it deals with “what a drug does to the body”.
Pharmacy: It is the science of collection, identification, selection, purification, isolation, preservation, standardization, synthesis, quality control and dispensing of medicinal substances.
Pharmaceutics: It is the large-scale manufacturing of the drugs, and the company is called as Pharmaceutical Ltd.
Pharmacognosy: It is the study of the identification of sources of drugs and study of physical and chemical properties of such substances.
Therapeutics: It is the practical branch of medicine dealing with the science and art of the treatment of diseases.
Pharmacotherapeutics: It is the treatment of diseases by means of drugs. It utilizes information on drugs obtained by pharmacodynamic studies.
Empirical therapeutics: It is the therapy based on clinical evidence that the drug is effective even if the 4mechanism of action of drug is unknown, i.e. during ancient time, chaulmoogra oil was used for the treatment of leprosy and mercurial compounds were for syphilis.
Chemotherapy: It is the treatment of systemic infection or malignancy with the drugs which are having selective toxicity for the infecting organisms/malignant cells with no or minimal effect on the host cells.
Chemotherapy has two components:
- Chemotherapeutic agents: These are the substances, which kills or inhibits the invading microorganisms (malignant cells) with no or minimal pharmacodynamic effect in the recipient cells.
- Pharmacodynamic agents: These are the substances having pharmacodynamic effects in recipient cells.
Toxicology: It is the branch of science, which deals with the study of untoward effects of any substance including drug toxicities or poisoning, whether because of internal or external exposure, and relating to both immediate and long-term implications in the realm of human ecology.
Clinical pharmacology: It is the scientific study of the effects of drugs in man. It provides information's regarding usefulness, efficacy, potency, toxicity and safety of new drugs in human (Patients).
Materia medica: It is the older term for a branch of pharmacology which concerned with the literature on sources, description and preparation of drugs.
Pharmacopoeia: It is an official monograph/compendia, containing a selected list of the established drugs, their chemical and structural formulae, solubility information, description, identification, purity data, direction for storage and dosages.
National formulary: These are the publication of different countries that included various informations on the products (formulations), available to prescribers in the respective countries. The national formulary is a smaller and much more handy book.
Recent Arrived Branches in the Pharmacology are:
Biotechnology: The branch of science which deals with the production of drugs, medicines and other useful products by biological means, i.e. by using recombinant DNA technology. (e.g. Production of antibiotics, hormones, etc. from microorganisms).
Pharmacogenetics: It is the branch of Pharmacology which deals with the study of genetic effect or influences on responses to drugs. In other words it deals with the study of genetically determined variations in drug responses.
Pharmacogenomics: This is the branch of Pharmacology, which overlaps the Pharmacogenetics by definition. It deals with the study of choices of drug therapy in different individuals on the basis of available genetic informations.
Pharmacoepidemiology: Branch of Pharmacology which deals with the study of drugs in the society (at population level).
Pharmacoeconomics: This Pharmacological branch aims to quantify in economic terms the cost and benefit of drugs used therapeutically.
Pharmacovigilance: It includes detection, assessment understanding and prevention of adverse effects or any other drug related problems.
Drug Information Sources
Primary sources
- Original studies and reports in Journals.
- Monographs.
- Published conference proceedings and symposia.
Drug compendia
- Pharmacopoeias: Pharmacopoeia of India, British Pharmacopoeia, United State Pharmacopoeia, Extra Pharmacopoeia (Martindale), etc.
- National Formularies.
- Monthly Index of Medical Specialties: MIMS
- Current Index of Medical Specialties: CIMS
- Physicians Desk Reference.
- Advance Drug Review (ADR).
Books
- The Pharmacological basis of therapeutics: Goodman & Gillman.
- Basic and Clinical Pharmacology: B.G. Katzung.
- Pharmacology: H. Rang, M Dale and J Ritter.
- Lippincott's Illustrated Pharmacology: R Harvey & P. Champe.
- Essential of Pharmacotherapeutics: F. Barar
- Pharmacology and Pharmacotherapeutics: Satoskar, et al.
- Essential of Medical Pharmacology: K. D. Tripathi.
- Text book of Pharmacology: S. D. Seth
- Clinical Pharmacology: Laurence et al.
- DRUG