PHARMACOLOGY
Pharmacology comes from the word root ‘pharmac’ meaning medicine, and –logy, the suffix to study.
Pharmacology deals with the chemical nature of medications and their effects on the human body. In the medical
environment medications are usually referred to as drugs.
Names of Drugs - Drugs are categorised by their function. If they are used to treat inflammation they are called
antiinflammatories, if they are used to control high blood pressure, they are called antihypertensives, if they are
used to fight bacterial infections they are called antibiotics. These are group names.
Within each group, drugs are divided up according to their generic names. The generic name is the name that
distinguishes the individual drug. However drugs have more than one name and they are usually sold under a
trade name. This is the name given to them by the company that sells them. More than one company can sell the
same drug and so although a drug only has one generic name, it can have many different trade names.
A parallel to the way drugs names are divided can be seen in the way species are labelled.
Groups Name
Generic Name
Trade Name
Lucy
Emily
Helen
female
human
Martin
Luke
Kyle
male
It works in a similar way with drugs. Take some common pain relievers (analgesics)
Groups Name
Generic Name
Trade Name
Panamax
Panadol
Dymadon
paracetamol
analgesics
Bex
Aspro
Dispirin
aspirin
Panamax, Tylenol, Panadol and Dymadon are trade names of the one drug, paracetamol. They are sold by three
different companies and have different packaging. The tablets may have a different shape but each of these drugs
contains exactly the same active ingredient, 500mg of paracetamol. The same applies for aspirin.
The only difference is the way in which the names are written. Generic names are not owned and do not need to
be written with a capital. Trade names are registered and, like a person’s name, must be written with a capital.
Routes of administration
Drugs can be administered to a patient in variety of ways. This varies depending on what type of drug it is, how
quickly it produces an effect in the body, what type of side effects it has, and whether the patient is conscious or
not. The route is usually described using the prefix ‘per’, meaning ’through’. Most routes have corresponding
abbreviations.
Term
Per oral
Inhaled
Sublingual
Topical
Intramuscular
Meaning
Through the mouth
Breathed into the lungs
Under the tongue
On the skin
Into the muscle (usually an
PHARMACOLOGY
Abbreviations
PO, O
SL
top.
IM, IMI
Types of medication
Tablets, syrups, powders
Sprays or powders
Certain tablets
Lotions, powders, creams
Solutions for injection
1
Intravenous
(injection)
Per vaginal
Per rectal
Drug Actions
injection)
Into the vein (usually an
injection)
Into the vagina
Into the rectum
IV, IVI
PV
PR
Solutions specifically for
injection
Pessaries, douches
Suppositories, enemas
Side effects
Not all affects of drugs are positive. Many drugs have side effects and although the drug may be effective in one
part of the body, it can cause problems in another area. For example, aspirin relieves pain but it can cause
irritation of the gastric mucous membrane, and also can be a trigger for asthma. People who are sensitive to these
side effects should avoid using aspirin.
Contraindications
Drugs are contraindicated (cautioned against) if it could cause undesirable or dangerous effects. For example,
aspirin is contraindicated for people with gastric ulcers or asthma.
Cumulation
Some drugs are stored in the body tissue for long periods of time. If the patient takes too high a dose for too long,
the drug can accumulate in the body and cause toxic effects. For this reason, some drugs require the patient to
have regular blood tests to check the level of the drug in their system. If the level is too high, the dose of the
medication is adjusted. For example, digoxin is a common drug used to treat cardiac arrhythmias. It works by
slowing and strengthening the heartbeat. However, if too much digoxin accumulates in the body the heart could
become too slow and the patient could die.
Tolerance
As the body becomes accustomed to the effects of a drug, larger doses of the drug are needed to achieve the
desired effect, for example drugs of addiction such as pethidine and morphine.
Common types of drugs
You will see from the following table that most of these medications work to stop something (hence the prefix anti-,
meaning against).
Type of drug
Action
Antihistamine
Works against allergies
Antipyretic
Works to decrease temperature (pyr/o means fire or heat)
Analgesic
Works to stop pain
Antiarrhythmic
Works to stop abnormal heart beats
Antifungal
Works to overcome fungal infestations
Antibiotic
Works to overcome bacterial infections
Diuretic
Works to increase the amount of fluid filtered by the kidneys
Vaccine
Works to protect the body from infectious diseases
Antidepressant
Works to overcome depressive illness
Anti-inflammatory agent
Works to suppress inflammation in soft tissue
Activity 1 What would be the most appropriate type of drug for each of following patients?
Patient Disorder
Which drug should the patient be
treated with?
A
Suffers from arthritis
B
Suffers from fluid retention
C
Has cardiac arrhythmias
D
Has chronic depression
E
Has a high temperature
F
Has myalgia
G
Has a bacterial infection
PHARMACOLOGY
Types of drug
antibiotic
antipyretic
antidepressant
antiarrhythmic
analgesic
diuretic
anti-inflammatory
2
Dangerous Drugs
All medications are potentially poisonous substances. Medications fall into two basic categories:
1) Prescription medication - these are drugs that can only be dispensed only with a medical prescription written by
a registered doctor, for example, antibiotics.
2) Over-the-counter medication - these are drugs that can be purchased without a script, for example, aspirin.
A medical practice will have a moderate supply of prescription medication on the premises. While these drugs can
be an incentive for theft, prescription pads are also targeted. Never leave prescription pads lying in view of patients
and encourage doctors to keep these pads in locked cupboards or drawers.
The Poisons Act of 1966 describes the Australian laws regarding the storage and handling of all medications. The
two schedules that apply specifically to medical practices are Schedules 4 and 8. As a medical office worker you
will have some degree of contact with these medications. Although the doctor and nurses will be responsible for
administering the medications to patients you may be responsible for checking and recording stock numbers,
ensuring valid use-by dates and ordering new supplies.
Medications are potentially lethal substances and the misuse or theft of these medications is a crime punishable by
gaol. It is essential that you follow the laws and procedures associated with these drugs at all times.
Schedule 4 - restricted substances
These are medications that are for sale only on prescription. Schedule 4 medications include mildly addictive drugs
such as those used to treat sleeping disorders, as well as non-addictive substances including as hormones,
antidepressants and anti-inflammatories. These medications must be securely stored and if they lost or stolen the
incident must be reported to the police and the Pharmaceutical Services Branch.
Schedule 8 - drugs of addiction
Schedule 8 medications include highly addictive drugs such as morphine, pethidine and cocaine. Unauthorised
possession of these drugs is illegal. These medications should be kept in a separate, locked cupboard that is
securely attached to the wall or floor. Doctors are primarily responsible for these medications and often carry them
in a locked bag. It is law that these medications be recorded in a drug register that is kept on the premises. This
register should show all transactions involving the drugs; the amount of stock received, the date the medication
was administered, who received it, what dose was given, and how much, if any, was discarded. All entries should
be made in ink, signed and dated. Any mistakes should be explained in a footnote, initialled, and dated. Any loss
or theft of these medications must be immediately reported to the police and to the Pharmaceutical Services
Branch.
Consumer Product Information (CPI)
Consumer Product Information is the written information that accompanies a medication and tells the consumer
about the drug: what it is, when and how it should be taken and possible side effects.
Pharmaceutical Benefits Scheme (PBS)
The Pharmaceutical Benefits Scheme is provided by the Commonwealth Government. PBS subsidies drugs so
that although they can cost hundreds of dollars, the public can purchase them for much less.
PBS Safety Net is a threshold where, after a specified maximum amount is paid per year, medication will be
cheaper of free for the rest of that year.
MIMS – Monthly Index of Medical Specialities
Trade names change frequently and both trade and generic names can be long and difficult to spell. If you are in
any doubt you should look the name up in MIMS. MIMS is a manual that describes all the current drugs along with
product information. Most doctors subscribe to MIMS and receive a new edition four times a year. The index has a
listing of most current drug group, generic and trade names.
PHARMACOLOGY
3