What Everyone Should Know About Drugs
Faith in Action Health Series
Drs. Susan R. Levy and Audrey K. Gordon
May, 2009
Basic Terms and Concepts for Discussing Drugs
Drug: Any substance other than food which, when introduced into the body, alters the body or its functions. Food can also affect the body and interfere with the body processes, or react with some drugs, but is considered differently. All drugs act chemically with the body, whether they are “natural” or manufactured. Their relative dangers and strengths and usages are based on the consideration and combination of four basic principles.
1. The chemistry of the drug itself. It is only since the 19th century that drug chemistry has been studied. We first isolated actual chemicals in “naturally” occurring plants and roots etc. which were discovered to effect body processes. These first isolations were basically by hit or miss observations over centuries in various civilizations. We now know how these chemical substances interact with specific chemicals in the body, and we can manufacture the specific chemicals we call drugs without other adulterants found in nature. The body always views and acts chemically, not by who made what. Chemistry is directly related to possible interaction with other drugs or foods.
2. How a drug is taken into the body, or the route of administration. This influences drug effects. In general, longer duration of getting a drug totally into the body gives a more sustained gradual dosage. If a large dose (sometimes needed) enters the body all at once (intravenous) it raises the amount higher immediately, reaching the dosage level and not having to go through any breakdown or absorption in the digestive system, etc. The most controllable and common way to take drugs is oral administration.
a. oral. (including taking with, or before or after, eating)
b. inhalation
c. injected (sub cutaneous), (intramuscular), (intravenous)
d. transdermal absorbed through skin via creams or time released patch
e. absorbed through anal or vaginal route
When a drug has to travel through the blood system to get to its site of action, we call it a systemic drug. If a drug only or mainly acts at the site of application it is termed a locally acting drug.
3. Drug Dosage: The amount of a drug taken at one time. Dosage is based on the effect of the drug the individual or physician wants to achieve, as many drugs have different good effect, as well as different untoward effects, at different dosages. In general, the higher the dose of any drug, the more systems in the body, or effects, the drug will have, especially increasing the chance for untoward effects. Higher dosages are responsible for leading to more complicated or dangerous problems.
Drugs which have to be used in higher dosages for a specific medical effect or need to be used, and have dangerous effects, at low dosages are usually classified as prescription or illicit (in many cases) drugs. Over the counter (OTC) drugs usually are safer at dosages most people would use to get the medicinal effects they need with some “dosage room to spare.” Any drug can be misused or dosed incorrectly.
By thinking about the relationship between a drug’s medical use and dosage, you can see why drugs used as systemic anesthetics would be immediately classified as dangerous because the dosage needed to get the desired medical effect puts a person clinically near the lethal dose.
Concepts associated with dosage are also frequency of taking, bioavailability, and drug elimination from the body. For example, if a drug is not eliminated from the body efficiently, there can be drug build up, even when taking the same original dose!!! This could lead to toxic or even lethal doses. Drug elimination is key to the safety of many drugs. Drugs are usually broken down by the kidneys, liver and oxidation or a combination.
4. Site of interaction. Drugs work by acting on the surface of the cells, within the cells or in extracellular fluids of the body. They enter a cell in the same way normal body chemicals do and in some way are similar in structure to a normal chemical of the body. The new drug may participate or replace some of what the body chemical does, but effects can be exceedingly complex from there. For example, drugs can enhance the release of naturally occurring body chemicals; (example some diabetes pills for type 2). Using the same example, if there is not enough insulin being produced, that individual may need insulin to be directly supplied by injection or pump. There is also a third option with drugs that make the insulin more available by reducing how quickly it is broken down or reuptake.
So drugs can act very complexly, to block a normal manufacturing process, a storage process, affect a releasing process or affecting the transport system within the body. If drugs are lipid soluble, like some vitamins, they can store in fat cells, thus remaining in the body for longer periods of time, not available for breakdown or excretion, and possibly accumulating for higher dosage, and possibly slowing down the cells metabolism as well.
When people talk about drug actions, it is not possible to classify all drugs simply by their major known action because of the four principles so far discussed. There are several different classification systems and it depends what you really need to know. Brand names/generic… Licit, Illicit, OTC…Chemical names and families… Using what we already know from this short intro, consider these points when choosing a drug or medication by reading labels or discussion with your physician.
