Definitions in Pharmacology

Definitions in Pharmacology

Pharmacology is the study of knowledge of the history, source, physical and chemical properties, compounding, biochemical and physiological effects, mechanism of action, absorption, distribution, biotransformation and excretion of drugs.

It is also defined as an experimental science dealing with the properties of drugs and their effects on living system.

Biochemical Pharmacology is the study of biochemical changes in the body occurring as the result of administration of drugs

Clinical Pharmacology is the study of evaluation of clinical usefulness of drugs in the diseased animals.

 

Chemotherapy is the branch of pharmacology dealing with drugs that selectively inhibit or destroy specific agents of disease such as bacteria, virus, fungi, and other parasites.

 

Chrono-pharmacology is the study of drug effects in relation with circadian rhythm.

Comparative Pharmacology is the study of relative effects of drugs in the diseased individual.

Ethnopharmacology is the study of use of drugs in animals / human beings by ethnic (native tribes) groups pertaining to that particular place.

Experimental Pharmacology is the study of determining the effects of drugs on different systems of the body and their mechanisms of action by using experimental animals.

 

Geriatric pharmacology The study of use of drugs in senile / old patients.

 

Molecular Pharmacology The study of molecular mechanisms of drugs’ action.

 

Paediatric pharmacology The study of usage of drugs in young patients.

Pharmacoeconomics aims to quantify in economic terms the cost and benefit of drugs used therapeutically.

Pharmacoepidemiology is the study of drug effects at the population level. It is concerned with the variability of drug effects between individuals in a population and between populations.

Pharmacometrics is the study of the techniques used in the measurement of drug effects to the administered dose of drug.

Pharmacogenetics is the study of genetically determined variations in animals that are revealed by the effect of drugs. Originally, pharmacogenetics focused on familial idiosyncratic drug reactions, where affected individuals show an abnormal-usually adverse-response to a class of drug. It now covers broader variations to drug response, where the genetic basis is more complex. Pharmacogenomics is a term that overlaps with pharmacogenetics.

Pharmacogenomics is a recent term that has been introduced. It overlaps with pharmacogenetics. This term describes the use of genetic information to guide the choice of drug therapy on an individual basis. The underlying assumption is that differences between individuals in their response to therapeutic drugs can be predicted from their genetic make-up.

 

Production pharmacology The study of use of drugs for the purpose of improving production (e.g. milk production, meat production, etc.).

 

Systemic pharmacology The study of use of drugs for different ailments of different systems in the body.

Veterinary pharmacology The study of use of drugs in veterinary patients.

Toxicology is the study of poisonous effects of drugs and other chemicals with emphasis on detection, prevention and treatment of poisonings.

Pharmacodynamics is the study of the biochemical and physiological effects of drugs and their mechanisms of action. It is the response of the organism to the action of a drug in the absence of a disease. Pharmacodynamics is what the drug does to the body.

Pharmacokinetics is the study of the actions of the drugs in the body over a defined period of time. It deals with the absorption, distribution, biotransformation and excretion of the drug. Pharmacokinetics is what the body does to the drug.

Pharmacy is the science that deals with the preparation, formulation, manufacture, standardization, preservation and dispensing of drugs. The term pharmacy also indicates the place where drugs are dispensed or sold.

Pharmacognosy is the study of the source of drugs. It also deals with the physical and chemical properties of drugs.

Materia medica is an obsolete didactic subject that was concerned with pharmacy, posology, pharmacognosy and indications for therapeutic use of the drug.

Drug is broadly defined as any chemical agent that affects processes of living. Drug is also defined as any chemical agent except food that is used to promote or safeguard the health of human beings or animals. It is also defined as 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. The word drug is derived from a French word 'Drogue' meaning a dry herb.

Over the counter drugs (OTC – drugs) are those preparations that can be sold without any restriction because they can be adequately labeled for layman use.

Prescription drugs are drugs that can be used only on the order of a licensed veterinarian/physician/dentist/surgeon. They are also known as legend drugs.

Essential drugs are agents that satisfy the healthcare needs of majority of the population. They should therefore be available at all times in adequate amounts and in appropriate dosage form.

Pro-drugs are drugs that are inactive or have a low order of activity in the form administered and are metabolized to the active form in the body.

Hard drugs are drugs used for non-medical purposes that are liable to disable the individual seriously as a functioning member of the society by inducing severe psychological and/or physical dependence. E.g. Heroin

Soft drugs are drugs used for non-medical purposes that are less dependence producing. There may be psychological dependence but not physical dependence, except with heavy dose. E.g. Amphetamine.

Nootropic drugs are drugs that affect the intellect. These drugs are claimed to enhance learning, increase brain resistance to stress including hypoxia and stimulate brain metabolism especially in senile patients. E.g. Piracetam

Orphan drugs are drugs or biological products useful for diagnosis / treatment / prevention of a rare disease condition for which there is no reasonable expectation that the cost of developing and marketing it will be recovered from the sales of that drug.

E.g. Acetylcysteine. These drugs may be, life saving for some patients, but are not commercially available.

Metrology is the study of weights and measures as applied to the preparation and administration of drugs.

Posology is the study of the medicine dosages, which varies with the species of animals, the intended effect of the drug and the individual tolerance or susceptibility.

Dose of the drug is an estimate amount of a drug, that when administered by a particular route to a certain species is most likely to produce a certain intensity of response.

It is the quantity of medication to be administered at one time.

Dosage is the determination and regulation of doses.

Loading dose is one or a series of doses that may be given at the onset of therapy with the aim of achieving the target concentration rapidly.

Maintenance dose is a series of relatively small doses that follow the loading dose in order to maintain an effective concentration in the bio phase.

Ceiling dose the dose at which the maximum effect is achieved, further increase in dose level will not cause further increment in response level.

Placebo is a vehicle for cure by suggestion and is surprisingly often successful though only temporarily. It can be used as a control in scientific evaluation of drugs and to benefit or please a patient not by pharmacological actions but by psychological means.  (Latin: Placebo - I shall be pleasing or acceptable). Placebo reactor is an individual who reports changes of physical and mental state after taking a pharmacologically inert substance.

Chemotherapy is the branch of pharmacology dealing with drugs that selectively inhibit or destroy specific agents of disease such as bacteria, viruses, fungi and other parasites. Use of this term has been extended to the use of drugs in the treatment of neoplastic diseases.

Empirical therapy is the use of certain agents that prove successful in a series of cases of the same disease, although, it is not possible to explain their actions. Their value has been demonstrated by experience.

Rational therapy is the term used with reference to the application of remedial measures, which can clearly explain the reasons for their application. Rational therapy is based on a thorough knowledge of the normal physiology, changes in physiology due to pathological conditions and the pharmacological basis for use of the drug. This implies a precise diagnosis and knowledge of the etiology of affection, so that we can act directly or indirectly on the causes which produce it and an intimate knowledge of the actions of the drugs, which we employ.

Curative therapy is the therapy aimed at bringing about a cure in the patient, like the use of antimicrobials in a bacterial infection.

Prophylactic or preventive therapy is the therapy aimed at preventing the occurrence of a disease, like the use of vaccines for preventing bacterial and viral infections.

Symptomatic or palliative therapy aims at treating the condition based on the symptoms and providing relief to the patient without actually spending time on finding the cause of the disease, like the use of anti convulsants in epilepsy.

Replacement therapy aims at replacing the constituents to the normal level when there is a reduction in the level of the constituent due to some pathological condition like fluid and electrolyte replacement in dehydration.

Additive therapy is the therapy given to add on to the existing level of the normal constituent even though there may not be a reduction in the level of that constituent, like the use of anabolic steroid to build up body mass.

Iatrogenic disease means physician caused disease i.e. disease consequent on following medical advice or intervention. Iatrogenic was first applied to disorder induced in the patient by autosuggestion based on physical examination or manner of examination or discussion by the doctor.

 

Side effects are unwanted but often unavoidable pharmacodynamic effects that occur at therapeutic doses.

 

Adverse effects are any undesirable or inintended conseqence of drug administration which include all kinds of noxious effect – trivial, serious or even fatal.

 

Toxic effects are the result of excessive pharmacological action of the drug due to overdosage or prolonged use.

Drug dependance is a state in which use of drugs for personal satisfaction is accorded a higher priority than other basic needs, often in the face of known risks to health.

Drug abuse refers to use of a drug by self medication in a manner and amount that deviates from the approved medical and social patterns in a given culture at a given time.

Drug addiction is a pattern of compulsive drug use characterized by overwhelming involvement with the use of a drug.

Drug habituation denotes less intensive involvement with the drug, so that its withdrawal produces only mild discomfort.

Teratogenicity refers to capacity of a drug to cause foetal abnormalities when administered to the pregnant mother.

Carcinogenicity refers to a drug to cause cancer.

Mutagenicity refers to a drug to cause genetic defects.

Tolerance means requirement of higher dose of a drug to produce a given response and is a widely occurring adaptive biological phenomenon.

Cross tolerance is the development of tolerance to pharmacologically related drugs.

Tachyphylaxis is the rapid development of tolerance – doses of a drug repeated in quick succession result in marked reduction in response, usually seen with indirectly acting drugs.

Drug resistance refers to tolerance of microorganisms to inhibitory action of antimicrobials.