Why Do Medicines Come in Different Forms?
Sometimes it seems like there are more medicines than there are diseases, and it can be hard to keep them straight. Some medications can be bought over the counter at pharmacies or other stores. Others require a doctor’s prescription. A few medicines are available only in hospitals.
Medicines are chemicals or compounds used to cure, halt, or prevent disease; ease symptoms; or help in the diagnosis of certain illnesses. Advances in medications have enabled doctors to cure many diseases and save lives. These days, medicines come from a variety of sources. Many were developed from substances found in nature, and even today many are extracted from plants. For example, one medicine that is used to treat certain cancers comes from the Pacific yew tree.
Some medicines are produced in a laboratory by mixing together a number of chemicals. Others, like penicillin, are byproducts of organisms such as fungus. And a few medicines are even biologically engineered by inserting genes into bacteria that make them produce the desired substance.
When we think about taking medications, we often think of pills. But medications can be delivered in many ways. Medicine is given in different form because of the necessity for convenience or for speed. It can be given by mouth (orally) in the form of tablets, capsules or draughts. It can be inhaled in the form of gases, fine aerosols or, very rarely, exceedingly fine powder.
Injections of medicine are given subcutaneously (beneath the skin), intramuscularly or intravenously. Sometimes solid implants in the form of tablets may be placed subcutaneously. Injections may also be given in the spine or brain. Medicines can be given through the rectum as solids (suppositories) or enemas or through the vagina as pessaries or douches. Finally, there are solutions, powders, creams and ointments which are paced locally on the skin.
Convenient medicines are those which can be taken or administered easily by the patient himself. Oral medicine and inhalations are convenient and a great deal of research is carried out to make these more palatable. Manufacturers prefer oral preparations because they can be attractively colored and flavored and made impressively mysterious in size and shape. They can also be code-stamped or named for identification. Injections have to be sterile and kept in appropriate containers and are therefore relatively expensive.