Definitions
Active ingredient
Ingredient that alone or in combination with one or more other ingredients is considered to fulfil the intended activity of a medicine.
• Acute care
A type of health care in which a patient is treated for an acute (immediate and severe) episode of illness, for the subsequent treatment of injuries related to an accident or
other trauma, or during recovery from surgery.
• Adherence
The extent to which a person’s behaviour - taking medication, following a diet, and/or executing life-style changes, corresponds with agreed recommendations from a health care provider.
• Adverse reaction
A response to a reaction which is noxoious and unintended and which occurs at doses normally used in man for the prophylaxis, diagnosis or therapy of disease or for the restoration, correction or modification of physiological function.
• Batch (Lot)
A specific quantity of material produced in a process or series of processes so that it is expected to be homogenous within specified limits.
• Bioavailability
It is defined as, "the rate and extent to which the active substance or active moiety is absorbed from a pharmaceutical form and becomes available at the site of action".
• Bioequivalence
Two medicines are bioequivalent if they are pharmaceutically equivalent or pharmaceutical alternatives and if their bioavailabilities after administration in the same
molar dose are similar to such degree that their effects, with respect to both efficacy and
safety, will be essentially the same.
• Bio-similar
It is defined as, "a biological medicine that is developed to be similar to an existing biological medicine (the “reference medicine”)". Biosimilar medicines can only be
marketed following the patent expiry of reference medicine.
Clinical pharmacology
It is defined as, "the study of effects of the pharmaceuticals in humans".
Defined daily dose (DDD)
The DDD is a unit of measurement defined as, "the assumed average maintenance dose per day for a pharmaceutical used for its main indication in the adult".
Disease
A failure of the adaptive mechanisms of an organism to counteract adequately, normally or appropriately to stimuli and stresses to which the organism is subjected, resulting in a disturbance in the function or structure of some part of the organism.
Efficacy
It is the extent to which an intervention does more good than harm under ideal circumstances.
Historical Landmarks
The knowledge of primitive pharmacology developed from human experiences with use of plants. Some plants were safe while others were toxic.
The oldest recorded event cites about events in 16th Century bc when beer, turpentine, myrrh, juniper berries and poppy and other therapies were described to treat disease. Similar historical records exist for most ancient civilizations including the Sumerian, Indian
and Chinese.
In India, Ayurveda has older traditions even before 16th century BCE. Sumerians around 3400 BCE cultivated the opium poppy in lower Mesopotamia and recorded its action in clay tablets. It was referred to as the “joy plant” and its reputation lead to its spread across
neighbouring civilizations like Egypt. Around 460 BCE Hippocrates, a famous Greek physician
and teacher of medicine, described opium as having narcotic properties and described use of opium in treating internal diseases. In 330 BCE, Alexander the great, introduced opium to Persia and India and by the year 400 it reached China. In the 10th century, the noted Islamic physician Avicenna of Persia described opium as the “most powerful stupefacients”. About the year 1200, the Indian medical treatises The Shodal Gadanigraph and Sharangdhar-Samahita describe the use of opium for diahorrhoea and sexual debility. In the 1300’s opium
disappeared from European historical record till 1527; during which Paracelsus prescribed
opium as a pain killer.
The modern era began in 1680 when the English apothecary, Thomas Sydenham introduced Sydenham’s Laudanum which mentioned about many opium proprietary brands
useful for various ailments. In 1803, the German Friedrich Serturner dissolved opium in acid and then neutralised it with ammonia resulting in formation of morphine which exhibited long-lasting and predictable effects. By 1827, morphine became a commercial product. In 1874, an English researcher, Wright synthesised heroin which went into commercial
production in Germany by 1898.
Scope of Pharmacology
Pharmacology is related to action
and uses of drugs. In development of new drugs, pharmacology has greatest contribution. It has two main components: pharmacodynamics and pharmacokinetics.
Pharmacodynamics deals with what drug does to the human/animal body. It involves study of action of drugs on receptors, its mechanism of action, indications for clinical use, contra-indications and adverse reactions caused by drugs.
Pharmacokinetics deals with what body does towards drugs. It has four main components: Absorption, Distribution, Metabolism and Excretion (ADME). Out of these four components, absorption, distribution and excretion are dependent on transport through membranes without any chemical change in the entity. In metabolism, there is chemical change in the moiety because of action of enzymes in the
body. Cytochromal enzymes in the liver are the main metabolising enzymes in the liver. A drug may have n number of metabolites. Every metabolite can have different action in the body. Thus, what we observe as action(s) of drugs is the net effect of main drug moiety and its metabolites. Several factors can alter ADME of drugs. It is the main reason why we get different kinds of actions for the same drug in different individuals.
Clinical pharmacology and therapeutics primarily deals with actions of drug in human beings. It incorporates indications, therapeutic uses, contra-indications, posology, bioavailability, prescription writing and drug nomenclature.
The science of clinical toxicology is an extension of clinical pharmacology.
Forensic toxicology addresses to medico-legal aspects of use of drugs.
Pharmacovigilance is gaining vital importance in last few decades. It
involves study of adverse reactions of drugs and their safety. Based on observations on pharmacovigilance, some drugs have been withdrawn from the market due to severe
adverse reactions.