This document discusses various ways that drugs can be classified. It outlines therapeutic classification based on the condition treated, pharmacologic classification based on mechanism of action, chemical classification using chemical, generic and trade names, legal classification into schedules based on abuse potential, and teratogenic risk categories. The Anatomical Therapeutic Chemical Classification System with Defined Daily Doses is also introduced as a tool for drug utilization research. In summary, drugs can be organized by how they work, what they treat, their chemical properties, abuse risk, and safety in pregnancy to better understand their appropriate use.

1. Classifications drugs
(For nursing)
S. Parasuraman M.Pharm., Ph.D.,
Senior Lecturer, Faculty of Pharmacy,
AIMST University,
Bedong 08100, Malaysia.

2. Classifications drugs
• Drugs can be categorized in a number of ways. In
pharmacology, a drug can be classified by its chemical
activity or by the condition that it treats.
• In general, drugs are classified based on
– Therapeutic classification
– Pharmacologic classification (based on mechanism of
action and mode of action)
– Chemical classification
– Amalgamated classification
– Legal classification (Controlled Substances, Drug
Schedules, and Teratogenic Risks)

3. Classifications drugs- Therapeutic classification
• Therapeutic classification is diffed as organizing drugs is based
on their therapeutic usefulness in treating particular diseases.

4. Classifications drugs- Pharmacologic classification
• A pharmacologic classification refers to the way a drug works at
the molecular, tissue, and body system levels. The pharmacologic
classification addresses a drug’s mechanism of action, or how a
drug produces its physiological effect in the body.

5. Classifications drugs- Chemical classification
• The three basic types of drug names are chemical,
generic, and trade name.
• A chemical name is assigned using standard
nomenclature established by the International Union of
Pure and Applied Chemistry (IUPAC). A drug has only one
chemical name, which helpful in predicting a substance’s
physical and chemical properties. Example: Chemical
name for aspirin is 2-acetoxybenzoic acid.

6. Classifications drugs- Chemical classification
• The generic name of a drug is assigned by the U.S.
Adopted Name Council. Generic names are less
complicated and easier to remember than chemical
names. The Food and Drug Administration (FDA), the
official Pharmacopoeia, and the World Health
Organization (WHO), routinely describe a medication by
its generic name.

7. Classifications drugs- Chemical classification
• A drug’s trade name is assigned by the company
marketing the drug. The name is usually selected to be
short and easy to remember. The trade name is
sometimes called the proprietary or product or brand
name.

8. Classifications drugs- Controlled Substances,
Drug Schedules, and Teratogenic Risks
• Some drugs are frequently abused or have a high potential for
addiction.
• According to law, drugs that have a significant potential for
abuse are placed into five categories called schedules. These
scheduled drugs are classified according to their potential for
abuse:
– Schedule I drugs have the highest potential for abuse
– Schedule V drugs have the lowest potential for abuse

9. Classifications drugs- Controlled Substances,
Drug Schedules, and Teratogenic Risks
Drug
Schedule
Abuse
Potential
Potential for
Physical
Dependency
Potential for
Psychological
Dependency
Examples Therapeutic Use
I Highest High High Heroin, ecstasy Limited or no
therapeutic use
II High High High Hydromorphone
methadone,
eperidine, fentanyl
III Moderate Moderate High Ketamine,
anabolic steroids
Used
therapeutically
with prescription
IV Lower Lower Lower Alprazolam,
diazepam
V Lowest Lowest Lowest Cough
preparations
containing not
more than 200 mg
of codeine per 100
mL or per 100
grams
Used
therapeutically
without
prescription
U.S. Drug Schedules and Examples

10. Classifications drugs- Controlled Substances,
Drug Schedules, and Teratogenic Risks
• A teratogen is a substance that has the potential to cause a
defect in an unborn child during pregnancy. A small number
of drugs have been shown to be teratogenic, either in humans
or in laboratory animals. Classification of teratogenic risk
places drugs into categories A, B, C, D, and X.

11. Classifications drugs- Controlled Substances,
Drug Schedules, and Teratogenic Risks
Category FDA drug risk classification in pregnancy
A Controlled studies in women fail to show a risk to the fetus
and the possibility of fetal harm appears unlikely.
B Animal-reproduction studies have not shown a fetal risk or
adverse effect. Risks have not been confirmed in controlled
studies in women.
C Either studies in animals have revealed adverse effects on
the fetus and there are no controlled studies in women or
studies in women and animals are not available.
D There is confirmation of human fetal risk, but the benefits
from use in pregnant women may be acceptable despite the
risk.
X Animal and human studies have shown fetal abnormalities.
The drug is contraindicated in women who are or may
become pregnant.

12. Classifications drugs- Anatomical Therapeutic
Chemical Classification System with Defined
Daily Doses (ATC/DDD)
• The purpose of the ATC/DDD system is to serve as a tool for
drug utilization research in order to improve quality of drug
use.
• In the ATC classification system, the drugs are divided into
different groups according to the organ or system on which
they act and their chemical, pharmacological and therapeutic
properties.

13. Classifications drugs- Anatomical Therapeutic
Chemical Classification System with Defined
Daily Doses (ATC/DDD)

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