Drug Classifications and Effects

Introduction

Drug classification, or the grouping and organizing of drugs, is a common task for someone in the medical field who deals with healthcare documentation. Drug classifications are used frequently in the field and are necessary when beginning to understand a patient and his or her medical chart.

 

Drug Classifications

Healthcare documentation specialists such as medical coders and medical transcriptionists need to have a basic understanding of drug classifications. They should also be familiar with commonly ordered medications that are often documented in the patient's medical record. Many drug references organize drug listings by classifications and sub-classifications; therefore, a solid understanding of drug classes will make looking up unfamiliar generic and brand names faster and more efficient.

Remember, though, that medications may have several different effects, and therefore some references may cross-list them under more than one classification.

For instance, you might take an ibuprofen for one of several reasons—to ease a headache, to lower a fever, or to reduce inflammation.

Drug classifications are used very frequently in medical settings—in fact, you'll probably understand many of them without our definitions, probably from personal experience.

 

Analgesics are drugs that relieve pain (algesi/o means "pain"; an- means "without"). Some medications to relieve pain are available over the counter, while others require a prescription.

it's important to remember they may still cause side effects, interact with other medications, and may not be safe for everyone. 

In addition to being analgesics, acetaminophen and ibuprofen are also antipyretics because they lower fevers. Ibuprofen and naproxen are also anti-inflammatory agents because they reduce swelling and inflammation. Additionally, ibuprofen and naproxen are available in a higher strength with a prescription.

Analgesics and Antipyretics

Most common over-the-counter analgesics:

• Acetylsalicylic acid (aspirin)—Bayer, Bufferin
• Acetaminophen—Tylenol
• Ibuprofen—Advil, Motrin
• Naproxen—Aleve

Other anti-inflammatory agents include:

• Indomethacin
• Meloxicam (Mobic)
• Diclofenac

 

Narcotics are a sub-classification of analgesics. These potent drugs work to relieve severe pain. They're associated with side effects such as drowsiness, confusion, and constipation. Narcotics are classified as controlled substances because they can be habit-forming.

Here are some examples:

• Morphine
• Codeine
• Oxycodone
• Oxycodone with acetaminophen (Percocet)

*Reminder: It's important to keep the differences between generic and brand names straight in your mind. One way of doing that is to remember that in our examples, as in other medical documents, brand names are capitalized but generic names aren't (except when they start a sentence).

 

Anesthetics reduce or eliminate sensation. 

There are four general types of anesthetics:

• Topical anesthetics
• Local anesthetics
• Regional anesthesia
• General anesthesia

Topical anesthetics are used on the surface of the skin or other tissue. They numb the tissue to which they're directly applied.

Local anesthesia is for anesthetizing a small part of the body. It's often injected into the area and affects only that area. Common examples of local anesthetics include the following:

• Hydrocortisone acetate (Orabase)
• Lidocaine (Xylocaine) 
• Procaine (Novocain)

Regional anesthesia works in a similar way to local anesthesia, but it affects a larger part of the body. Examples of regional anesthesia include spinals, epidurals, and peripheral nerve blocks.

General anesthesia eliminates sensation in the whole body and renders the patient completely unconscious. Here are some examples:

• Halothane (Fluothane)
• Nitrous oxide
• Thiopental (Pentothal)

 

The mode of induction (how the anesthesia is administered) differs depending on the type of anesthesia.

General anesthesia is administered through the lungs or into a vein. Gas anesthetic is administered either with a face mask or through a tube placed in the trachea or bronchi.

Liquid anesthetic is administered with an intravenous pump.

Regional anesthesia is administered by nerve block, sometimes called simply "block." The anesthetic is injected along a nerve path to stop nerve impulses in that area.

Local anesthesia is administered by infiltration—the anesthetic is injected into the tissue of the area that needs to be anesthetized, where it spreads to adjoining tissue. Usually, the area anesthetized by this method is only a few cubic centimeters in size.

 

Who today would fear imminent death at the onset of a bad cough with a high fever? Until 1945, when penicillin became available for general use, infections were often life-threatening. Today, when a bacterial infection is suspected or diagnosed, we can take an antibiotic to stop the growth of whatever strain of bacteria is responsible for the disease.

Antibiotics kill or inhibit the growth of bacteria. Since 1945, pharmacologists have developed many other antibiotics to fight a broad spectrum of bacteria.

 

Antibiotics are divided into classes such as penicillin's, cephalosporins, sulfonamides, and quinolones.

Different types of infections require different antibiotics because no antibiotic can treat all the different types of bacteria that cause infection. The health provider will choose an antibiotic based on what type of infection it is and what organism is causing the infection.

You may have heard of sulfa drugs, or sulfonamides, a form of antibiotic drug very effective against urinary tract and GI infections. These antibiotics have been prescribed since the 1930s, but care must be taken as many patients experience allergic reactions to sulfa drugs. The major sulfa drug is trimethoprim sulfamethoxazole (Bactrim, Septra).

Examples of Antibiotics

• Penicillin V (Pen-Vee K, V-Cillin K)
• Benzathine Penicillin G (Bicillin) 
• Procaine Penicillin G (Wycillin, Duracillin)
• Ampicillin (Amcill, Omnipen)
• Amoxicillin (Amoxil)
• Tetracycline HCI (Achromycin V, Sumycin)
• Doxycycline (Oracea, Targadox)
• Erythromycin (E-mycin, Erythrocin, llosone, Pediamycin)
• Cephalexin (Keflex, Keflin)
• Gentamicin sulfate (Garamycin)

 

Drug Action and Effect

How do drugs do what they do? And how does the body react to the presence of drugs? These are big questions for pharmacologists. And the answers aren't just fascinating—they're also important to know. All drugs cause changes in cells, called drug action. This action in turn causes some physiological change in the body, or effect. Depending on the drug's action, the effect may be systemic (throughout the body) or local (limited to the area where administered).

Before it can take effect, a drug has to get where it's going. Once the drug is administered, the first phase of its journey through the body is absorption—getting into the bloodstream. The route of administration effects the speed of absorption, as do many other variables.

For instance, some oral drugs will be absorbed more quickly when taken on an empty stomach than when taken with food. However, some drugs irritate an empty stomach and should be taken with food. That's just one reason why it's always important to read labels!

Drugs have a "target" substance on the cell, called a receptor. The receptor might be a particular chemical that will react with the drug to speed up or slow down normal cell processes. The drug reaches the receptor by a process called distribution, in which the drug moves from the bloodstream across the cell membrane.

 

Once metabolized, or processed, the drug can do its work in the cell. It might depress or stimulate the cell's processes, destroy the cell or certain parts of the cell, or replace a substance in the cell that the body hasn't produced on its own (as with hormone replacement therapy).

The final phase of the drug's medicinal journey is excretion, the elimination of the waste products of drug metabolism. Most drugs leave via the kidneys, though some may be exhaled or perspired out of the body. Even the excretion of a drug can be a factor in its proper use. In patients with kidney problems, certain drugs can be contraindicated, or considered dangerous and ill-advised, because of the renal condition.

 

Drug Reactions and Interactions

Once a drug has entered the body and begun its action, there are many possible effects for which the healthcare provider must be alert while the patient is taking the medication. The effectiveness of the drug over time will be one consideration.

For example, does it lose potency or build up in the tissues? Healthcare providers must also alert for any possible effects of drug interaction, which occurs when two or more drugs that are used simultaneously alter each other's effects on the body.

The following are some terms related to the effects of drugs:

• Additive action—Two or more drugs act together without diminishing or increasing each other's effects.
• Antagonism—Two drugs decrease or cancel out one another's effectiveness.
• Cumulative action—The more a drug is given, the stronger its toxic effect on tissue. The dose may have to be reduced to limit damage to the body.
• Dependency—This is the psychological and physical need for a drug resulting in withdrawal symptoms when the drug is absent.
• Latrogenic disorder—This refers to pathology produced from medical care, including drug treatment.
• Idiosyncrasy—This is any unexpected effect. An example of idiosyncrasy is anaphylaxis (immune responses of milder degrees are termed hypersensitivity).
• Potentiation—One drug prolongs or intensifies the effect of another drug.
• Synergism—Two drugs act together to surpass the additive effect of the individual drugs. The whole is greater than the sum of its parts.
• Teratogenic effect—this refers to physical defects in a fetus caused by exposure to a drug (or other substance) during pregnancy.
• Tolerance—The more a drug is given, the weaker the effect of the drug. The dose must be increased to maintain the desired effect.
• Toxicity—This refers to a harmful or fatal effect from exposure to either a poison or a dangerous amount of a drug that's safe in smaller amounts.

 

The combined effects of medications can be either desirable or undesirable. Thus, you may hear about desirable synergism or undesirable synergism, desirable potentiation or undesirable potentiation, and so on. Therapeutic drugs often also have effects that are normal and expected but not quite what the doctor ordered. That is, they aren't part of the therapeutic plan; they just happen. These are called side effects, and they can be unnoticeable, mildly unpleasant or inconvenient, or even dangerous. Patients may be able to feel some side effects; however, other side effects of medications may be noticed as a result of lab work or a physical exam. This is why it's so important for the patient's medical record to contain an accurate list of all medications that the patient is currently taking.

The list at right contains several common side effects of various medications. You may already be familiar with many of these terms.

Anorexia (diminished appetite), impotence, anxiety, insomnia, blurred vision, irritability, breast tenderness, itching, bruising, lightheadedness, burning sensation, low blood pressure, chest pains, menstrual irregularities, confusion, nasal congestion, constipation, nausea, cramps, nervousness, depression, palpitations, diarrhea, rash, dizziness, restlessness, drowsiness, sweating, dry mouth/nose/skin, tingling, dyspnea (difficulty breathing), tinnitus (ringing in ears), edema, tremors, fatigue, twitching, fever, urinary frequency, flushing, urine discoloration, headache, urine retention, heartburn, vaginal discharge, hiccups, weakness, hives, weight gain

 

Key Points

• Many drug references organize drug listings by classifications and sub-classifications; understanding drug classes makes it easier to reference them.
• Analgesics are drugs that relieve pain. Antipyretics are drugs that lower fevers. Anti-inflammatory agents reduce swelling and inflammation.
• Narcotics are a sub-classification of analgesics used to relieve severe pain; they can also cause grogginess and are habit-forming so they're classified as controlled substances.
• Anesthetics reduce or eliminate sensation, allowing doctors to perform surgery. They include topical anesthetics, local anesthetics, regional anesthetics, and general anesthetics.
• Antibiotics kill or inhibit the growth of bacteria.
• All drugs can cause change in cells, known as the drug action, which in turn causes a physiological change in the body, or effect.
• Additive action means two or more drugs act together without diminishing or increasing each other's effects.