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Two components ofPharmacoepidemiology

1.Pharmaco

2.Epidemiology

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1.Pharmacology is the study of the effects of

medicines.2. Clinical Pharmacology is the study of theeffects of medicines in humans.

Pharmacoepidemiology can be considered,therefore, to fall within clinical pharmacology.

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Clinical pharmacology divided in 2 basic

areas: Pharmacokinetics

Pharmacodynamics

Pharmacokinetics is the study of the relationshipbetween the dose administered of a medicine and theserum or blood level achieved (medicine absorbtion,distribution, metabolism, and excretion).

Pharmacodynamics is the study of the relationshipbetween medicine level and medicine effect.

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Pharmacoepidemiology VS. Epidemiology

Epidemiology is the study of the distribution and

determinants of diseases in populations.

Epidemiology is divided in 2 basic areas:

1. Infectious diseases

2. chronic diseases

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PharmacoepidemiologyA relatively new applied field

Bridging between clinical pharmacology and

epidemiologyApplies the methods of epidemiology to the content

area of clinical pharmacology.

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HISTORICAL 1906US law: the Pure Food and Drug Act, response to excessive

adulteration and misbranding of the food and medicines available atthat time.

1937over 100 people died from renal failure as a result of the

marketing of elixir of sulfanilamide disolve in diethylene glycol. 1938Food, Drug and Cosmetic Act: pre clinical and toxicity testing

was required for the first time, and submit clinical data about safetyto the FDA prior to drug marketing.

Litle attention to adverse drug reaction until 1950: Chloramphenicolcould cause aplastic anaemia.

1952: the first textbook of adverse drug reaction was published. TheAMA council on Pharmacy and Chemistry established the first officialregistry of adverse drug effects, to collect cases of drug inducedblood dyscrasias.

1960: FDA began collect reports of ADR.

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DESI (Drug Efficacy Study Implementation)conducted by the National Academy of Sciences

National Research Council with support from the FDA:removal from US market of many ineffective drugs anddrug combination.

1960s: publication of a series of utilization studies,

provide the first descriptive information on howphysicians use drugs, and began a series ofinvestigations of the frequency of poor prescribing anddeterminants of poor prescribing.

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1960s

is the begining of the field ofPharmacoepidemiology

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MEDICINE USE & FACTORS

INFLUENCING PRESCRIBING

Defining pharmacoepidemiology and

medicine utilizationProcess of pharmacotherapy

Factors influencing prescribing

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Aims of Pharmacoepidemiology

To examine and judge pattern of medicine use

To determine how efficacy in clinical trials translatesinto effectiveness in the population

To evaluate the extents of risks Adverse medicinereactions

To evaluate the extents of cost

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DEFINING

MEDICINE UTILIZATION

Medicine utilization is defined as the marketing,

distribution, prescription, and use of medicines withspecial emphasis on the resulting medical, social, andeconomic consequences (WHO, 1997)

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FOCUSED MEDICINE

UTILIZATION STUDIES?

To identify problems of medicine utilization

To identify possible causing factors

To identify intervention for improvement

To evaluate intervention strategy

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PROCESS OF

PHARMACOTHERAPY Making of diagnosis and defining patients problem

Defining therapeutic goal

Defining interventions: Medicines & Non medicines Selecting medicines

Determining dose, route, frequency, and duration ofmedicine administration

Writing prescription

Providing information

Monitoring and evaluation

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FACTORS INFLUENCING

PRESCRIBING

Levels of knowledge, skills, and competence of

prescribersAttitude

Information and promotion

Patients demand

Medicine supply and availability

Peers and environmental

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Framework for changing medicine

use practicesPurpose and content

There are many different ways to improve medicine use practices. This unitwill expose you to a number of different strategies which have been tried to

improve medicine use, ranging from providing information to restrictiveregulatory measures, and the evidence for or against their effectiveness.Not all strategies are relevant or feasible in specific area, in specificprogram, or for every medicine use problem. However, this session willenable students to identify and choose among the possible interventionstrategies which might be considered in a given situation.

The case study will also make clear the need for carefully considering eachapproachs unintended effects before widespread implementation.

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OBJECTIVES

Students will be able to:

1. Identify particular medicine use problems, and placethem in the perspective of the factors underlying

problems in medicine use.2. Identify any different approaches to improve

problems in medicine use which have been tried inthe past.

3. Understand some of strehgths and weaknesses ofdifferent approaches in terms of demonstratedeffectiveness, cost, and suitability for specific placecontexts and medicine therapy problems.

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FACTORS WHICH INFLUENCE MEDICINE USE

Problems in medicine use can be caused by a wide rangeof factors, which differ in importance from problem to

problem and from setting to setting. Before trying tocorrect any problem in medicine use, it is helpful toidentify which factors are most important in causingthe problem at hand. Unless the proposed

intervention targets the appropriate causes of theproblem, it is unlikely to be successful.

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Several categories of factors which

should be considered as possiblecauses of a problem in medicine use.

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1. Characteristic of providers of care

Lack of knowledge about diagnosis, therapeutics, theefficacy and risks of particular medicines.

Acquired habits in diagnosis and treatment which may notreflect what providers actually know, but the patterns of

behaviour they have come to adopt. Beliefs about illness and medicines such as the increased

power of injections over oral medicines, which also do notalways reflect their level of scientific knowledge.

Personal economic motivations for prescribing ordispensing particular medicines, for example, medicinecompany incentives, dispensing fees, referrals to privatepractice, ect.

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2. The Summary of Medicine

Utilization Research

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Proven Effectiveness:

Face to face education focused on a fewprescribing problems

Structured medicine order formsPrescription audits/procurement review

plus feedback

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Possible Effectiveness:Essential medicine lists plus education

Standard treatment schedules pluseducation

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Ineffective:

Printed materials alone

Arbitrary limits on number/quantity of

medicines per prescriptionUnfocused education

Essential medicine lists alone

Standard treatment schedules alone

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New Medicine Development

In vitro and Pre clinical Toxicity: animal testing

Phase I: Human clinical trials

Phase II and Phase III: Human clinical trials

Phase IV studies: Post marketing surveilance andmedicine use experience

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Premarketing Risk Analysis To detect overt toxicity

To establish dose-response estimation ofpharmacologic and toxic effects

To assess medicine distribution to organ system

To identify metabolic, kinetic, and eliminationpathways

To assess carcinogenic potential To assess reproductive toxicity and teratogenic

potentials

To direct clinical safety assesssments

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Premarketing clinical investigations

Phase I:

Usually in normal volunteers with attention topharmacokinetics, metabolism, and both single dose

and dose-range safer Phase II:

Limited size, closely monitored investigations designedto assess efficacy and relative safety

Phase III: Full-scale clinical investigations designed to provide an

assessment of safety, efficacy, optimum dose, and moreprecise definition of medicine-related adverse effects

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Postmarketing Medicine Evaluation Phase IV Studies, Postmarketing Surveilance and

Medicine Use Experience

Efficacy

Effectiveness

Safety

Adverse Medicine Reactions

Economic Analysis

PHARMACOECONOMICS

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PHARMACOECONOMICS

Economic analysis of Pharmaceuticals

Introduces the concepts of clinical economics

Review some methodologic issues

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Dimensions of Economic analysis

Types of analysis: Cost-identification

Cost minimization

Cost-effectiveness

Cost -utility Cost-benefit

Viewpoints of analysis Provider, Payer, Patient, Society

Types of cost Direct costs: medical and non medical cost

Indirect cost

Intangible cost

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Changing a Medicine Use Problem

An Overview of The Process1. Examine

Measure Existing Practices

Improve diagnosis 2. Diagnose

4. Follow up Identify SpecificMeasure changes in outcomes Problems & Causes

Improve intervention

3. TreatDesign & Implement

Interventions