People tried to save their life using various natural pharmaceutical substances already in ancient times. More often they were vegetable extracts, but there were also used preparations that were gained from raw meat, yeast and waste of animals. Some pharmaceutical substances are available in vegetative or animal stuff in an accessible form, in connection with which medicine has successfully used a large number of medicaments of vegetative and animal origin (for example: castor-oil plant, opium, sea onion known still in ancient Egypt; mercury
known to ancient Hindus; foxglove, lily of the valley, adonis and many others widely used in folk medicine) since ancient times. Only by progress of chemistry people made sure that the therapeutic effect of such substances consists in the selective influence of certain chemical compounds on an organism. Later such compounds were gained by means of synthesis in laboratories.
The effect of medicaments is realized mainly by means of the change of physicochemical properties of the environment where cellular elements of the organism are situated; thus the effect can have a character of the chemical association of the medicament with the elements of the organism and in some cases can be accompanied by the complete destruction of cells under direct influence on their protoplasm. The physiological effect of the medicament is either excitation or inhibition of the vital activity of cellular elements; in this case the dose of the medicament plays a big role, as one and the same medicament in various doses can cause different effect — excite in small doses and inhibit (up to paralysis) in big doses.
The effect of the medicament depends on the age, state of health and individual features of the organism of the person who takes it. A number of medicaments in a respectively reduced dose have a stronger effect on children, than on adults (often toxic); women react to medicaments differently than usual in the period of menstruation, pregnancy, lactation; the medicament has abnormally strong effect on some people, that is explained with hypersensitivity of the organism to certain substances.
The ways of introduction of the medicament to the organism are quite variegated. More often medicaments are taken orally. Medicaments are introduced hypodermically – intramuscularly or intravenously with a syringe in order to avoid rapid decomposition of the medicament or irritation of the gastrointestinal tract or to achieve quicker effect. Some medicaments are introduced through the rectum or respiratory tract.
The external use of medicaments is considered as their introduction on skin and mucous membrane of eyes, nose, ears, mouth, urogenital tract (up to the entry of the urinary bladder and the cervical tract of the uterus), on mucous membrane of the rectum (up to the location of the interior sphincter).
Medicaments are decomposed and changed in the organism, and lose their toxic properties entering the chemical compounds with their salt and liquid (and sometimes inversely, acquire them) and in such or other form, are removed from the organism through the intestine, kidney, respiratory tract, sudoriferous glands, etc.
A preparation which is not known earlier and released for sale first by the manufacturing company or patentee, is called an original medicament. As a rule, preparation and forwarding of a new medicament to the market is a very costly and long process. Out of variety of known, as well as again synthesized compounds, those having maximum desired activity are detected and synthesized via the searching method on the basis of the database per their characteristics and computer modeling of the supposed biological activity. Limited clinical testings are conducted on the groups of volunteers after the experiments on animals in case of a positive result. If the effectiveness is confirmed, and the side effects are insignificant — the medicament goes to manufacturing, and the possible features of the effect are defined precisely and the undesirable effects are detected on the basis of the results of additional testings. The most harmful side effects are often detected namely during the clinical practice.