Pharmaco -Pharmaco -
epidemiology isepidemiology is
the study of thethe study of the
use of and theuse of and the
effects of drugseffects of drugs
in large numbersin large numbers
of people.of people.
What IsWhat Is
Pharmacology is the study of the effect of
Clinical pharmacology is the study of effect
of drug in humans
clinical pharmacology a risk benefit
assessment for the effect of drugs in patients
Epidemiology can be defined as the study of the
distribution and determinants of diseases in
1. Descriptive epidemiology describes disease and/or
exposure and may consist of calculating rates, e.g.,
incidence and prevalence. Such descriptive studies do
not use control groups and can only generate
hypotheses, not test them. Studies of drug use would
generally fall under descriptive studies.
2. Analytic epidemiology includes two types of studies:
observational studies, such as case-control and cohort
studies, and experimental studies which would include
clinical trials such as randomised clinical trials. The
analytic studies compare an exposed group with a control
group and are usually designed as hypothesis testing
Epidemiological studies can be
divided into two main types:
Pharmacoepidemiology then can also be defined
as the application of epidemiological methods to
Pharmacoepidemiology benefits from the
methodology developed in general epidemiology
and may further develop them for applications of
such methodology unique to
pharmacoepidemiology. e.g : pharmacovigilance
Pharmacovigilance is a type of continual
monitoring for unwanted effects and other safety-
related aspects of drugs that are already on the
In practice, pharmacovigilance refers almost
exclusively to the spontaneous reporting systems
which allow health care professionals and others to
report adverse drug reactions to a central agency.
The central agency can then combine reports from
many sources to produce a more informative safety
profile for the drug product than could be done
based on one or a few reports from one or a few
health care professionals.
The history of drug regulation parallels the
history of major adverse drug reaction
Recent data indicate that 100000 Americans
die each year from Adverse Drug Reactions,
and 1.5 million US hospitalizations each
year result from Adverse Drug Reactions;
yet, 20-70% of Adverse Drug Reactions may
tend to be
Reactions tend to be
Not related to dose
To optimize use of drugs, Clinical Pharmacology specifies
that therapy should be individualized, or tailored to the
needs of the specific patient at the hand. Doing so requires a
prescriber to be aware of the potential beneficial and harmful
effects of drugs in question and to know how elements of
patient’s clinical status might modify the probability of a good
For example consider a patient with a serious infection,
serious liver impairment and mild impairment of his or her
renal function. In considering whether to use gentamicin
treat the infection, it is not sufficient to know that
gentamicin has a small probability of causing renal disease.
A good clinician should realize that a patient who has
impaired liver function is at a greater risk of suffering from
this adverse effect than one with normal liver function
Potential Contributions Of Pharmacoepidemiology
A)Information which supplements the information
available from premarketing Studies- better
quantitation of the incidence of known adverse and
a. Higher precision.
b. In patients not studied prior to marketing e.g. the
elderly, children, in pregnant women.
c. As modified by other drugs and other illnesses.
d. Relative to other drugs used for the same
B) New types of information not available from pre-marketing studies.
1. Discovery of previously undetected adverse and beneficial effects.
a. Uncommon effects.
b. Delayed effects.
2. Patterns of drug utilization.
3. The effects of drug overdoses.
4. The economic implications of drug use.
C) General Contributions of Pharmacoepidemilogy
1. Reassurances about drug safety.
2. Fulfillment of ethical and legal obligations.
ReaReason to Perform
A. RegulatoryA. Regulatory
2.2. To obtain earlir approval for marketingTo obtain earlir approval for marketing
3.3. AAs a response to question by regulatory
4. To assist aplication for approval for
1. To assist market penetration by dokumenting the
safety of the drug
2. To increase name recognition
3. To assist in repositioning the drug
a. different outcomes e.g quality of life and economic
b. Different types of patients e.g the elderly
c. New indication
d. Less restrictive labeling
4. To protect the drug from accusation about advers
In anticipation of future product
1. Hypothesis testing
a. Problem hypothesized on the basis of drug structure
b. Problem suspected on the basis of preclinical or premarketing human
c. Problem suspected on the basis of spontaneous reports
d. Need to better quantitative the frequency of adverse effect
3. Hyphotesis generating – need depends on :
a. Wheather it is a new chemical entity
b. The safety profile of the class
C. The relative safety of the drug *ithin its class
d. The formulation
e. The disease tobe treated, including :
• Its duration
• Its prevalence
• Its severity
• wheathe alternative therapies are available
All drugs have adverse effects.
Pharmacoepidemilogy will never succeed in
preventing them. It can only detect them,
hopefully early, and thereby educate health
care providers and public, which will lead to
better medication use.
The net results of increased activity in
pharmacoepidemilogy will be better for
industry and Academia but most importantly,
for public’s health.