DRUGS: THEIR MAIN CHARACTERISTICS AND FORMS

Everyone knows that medicines, or drugs are chemical substances used to make you feel better when you are sick. These chemical substances can come from many different sources. Drugs are obtained from various parts of plants, such as the roots, leaves, and fruit. Examples of such drugs are digitalis (from the foxglove plant), and antibiotics such as penicillin and streptomycin (from plants called molds). Drugs can also be obtained from animals; for example, hormones are secretions from the glands of animals. Drugs can be made from the chemical substances which are synthesized in the laboratory. Some drugs are contained in food substances; these drugs are called vitamins.

Every drug must have a nonproprietary name, that is, a name that is available for each manufacturer of it to use. These names are commonly called “generic names”. Manufacturers often coin brand names to use in promotion of their particular product. In general, brand names are shorter and easier to use than the corresponding generic names.

The route of administration of a drug (how it is introduced into the body) is very important in determining the rate and completeness of its absorption into the bloodstream and speed and duration of the drug’s action in the body. There are many routes of drug administration. They are oral administration (by mouth); buccal administration (a medicine is placed in the cheek pocket and slowly absorbed); sublingual administration (for general effects throughout the body, when a medicine is placed under the tongue and slowly absorbed); rectal administration (for local and in some cases systemic effects, when it is used in the rectum); vaginal administration (for local and in some cases systemic effects when used in the vagina); parenteral administration (in the form of injection); inhalation (for local, and in some cases systemic effects, when inhaled into the lungs); and topical application (for local effects, when it is applied directly to the skin).

The dosage forms are the following: tablets, solutions, capsules (for oral administration); suppositories (for rectal administration); subcutaneous, intradermal, intramuscular, intravenous, intrathecal, and intracavitary injections (for parenteral administration); aerosols (for inhalation); lotions, creams, and ointments (for topical application).