DUS_Dr. Mansij Biswas

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Drug Utilization Studies Dr. Mansij Biswas, SYR Department of Pharmacology & Therapeutics Seth G S Medical College & KEM Hospital

Transcript of DUS_Dr. Mansij Biswas

Drug Utilization Studies

Dr. Mansij Biswas, SYR

Department of Pharmacology & Therapeutics

Seth G S Medical College & KEM Hospital

Introduction & Definition:

Pharmaco-epidemiology is the study of use and effects

or side-effects of drugs in large number of people with

the purpose of supporting the rational and cost effective

use of drugs in population, thereby improving health

outcomes.

WHO defines drug utilization research as, “the

marketing, distribution, prescription and the use of

drugs in a society with special emphasis on the resulting

medical, social and economic consequences.”(WHO,

1977)

June 7th, 2014INTRODUCTION TO DRUG UTILIZATION RESEARCH, WHO International Working Group For

Drug Statistics Methodology, WHO Collaborating Centre For Drug Statistics Methodology, WHO, 2003.2

Looking back…

Initiated in Northern Europe and The UK in the mid

1960s

Arthur Engel in Sweden and Pieter Siderius in Holland

described importance of comparing drug use between

different countries and regions

Differences in sales of antibiotics in six European

countries between 1966 and 1967 inspired WHO to

organize first meeting on drug consumption in Oslo,

1969

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Constitution of WHO European Drug Utilization

Research Group (DURG)

Development of a new unit of measurement, initially

called the agreed daily dose and later the Defined Daily

Dose (DDD), by researchers from Ireland, Norway &

Sweden

The first study used anti-diabetic drugs as an example

Among the first countries to adopt the DDD

methodology was the former Czechoslovakia

First comprehensive national list of DDD was published

in Norway in 1975

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Why drug utilization research?

The principal aim is to facilitate the rational use of

drugs in populations.

Rational use of medicines (RUM) is defined as

“Patients receive medications appropriate to their

clinical needs, in doses that meet their own individual

requirements, for an adequate period of time, and at the

lowest cost to them and their community” (WHO, 1985)

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Promoting Rational Use of Medicines: Core Components - WHO Policy Perspectives on

Medicines, No. 005, September 2002 5

Objectives:

Description of drug use pattern

Early signals of irrational use of drugs

Interventions to improve drug use – follow up &

assessing the impact

Quality control of drug use

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Description of drug use pattern : -

Drug utilization research will increase our understanding of

how drugs are being used by-

Estimating the numbers of patients exposed to specified

drugs within a given time period.

Getting extent of use at certain moment or area.

Estimating to what extent drugs are properly used,

overused or underused.

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Determining pattern or profile of drug use and the

extent to which alternative drugs are being used to

treat particular conditions.

Comparing the observed patterns of drug use for the

treatment of certain disease with current guidelines.

Giving feedback of the drug utilization data to

prescribers.

Assessing the potential magnitude of the problem

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Early signals of irrational use of drugs:

Comparing drug utilization patterns and cost

between different regions or time period

Comparing observed patterns of drug use with

current recommendation or guidelines for the

treatment of certain disease

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Interventions to improve drug use-follow

up:

Monitoring and evaluating the effects of measures

taken to improve undesirable patterns of drug use

Following the impact of regulatory changes or

changes in the insurance or reimbursement schemes

To which extent promotional activities of the

pharmaceutical industry and educational activities of

the society impact on the patterns of drug use

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Quality control of drug use:

Drug use should be controlled according to a quality control

cycle that offers a systematic framework for continuous

quality improvement

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Step 1 : PLAN –Analyze the current situation to establish plan for improvement

Step 2 : DO –Implement the plan on

small scale

Step 3 : CHECK –Check to see if

expected results are obtained

Step 4 : ACT – Revise plan or implement plan

on large scale

Types of drug use information

Drug based information

Problem or encounter based information

Patient based information

Prescriber based information

Cost based information

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A) Drug based informations

◦ Data on drug use on various levels, and

information on indications, doses and dosage

regimen is usually necessary

◦ Level of drug use aggregation : The level at

which data on drug use are aggregated will

depend on question being asked.

E.g. Hypertension

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Indication –

◦ For drugs with multiple indications, it will

usually be important to divide data on use

according to indication to allow a correct

interpretation of the overall trends.

E.g.-

◦ antibiotic utilization

◦ Use of beta-blockers

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B) Problem based informations

◦ Useful to address the question – how a particular problem is managed.

Questions that might be addressed:◦ Does the severity of the disease influence the

choice of single or combination therapy ?

◦ Is the management of newly-presenting patients different to that of patients already receiving treatment ?

◦ Are there likely to be any drug interactions with co-prescribed treatments ?

◦ Is the choice of drug influenced by evidence based outcome data ?

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C) Patient based informations

Information on demographic factors and other

details about the patient are useful

Age distribution – to assess the likelihood of severe

adverse effects with some drugs

Comorbidities of patient

Knowledge, beliefs and perceptions of patients and

their attitudes to drugs are important

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D) Prescriber based informations

This information is useful to understand how

and why drugs are prescribed.

◦ Some questions that might be addressed:

Are prescribing profiles influenced by the

prescriber’s medical education?

Do the prescribing profiles of specialists differ from

those of general practitioners ?

Does the age or gender of the prescriber influence

the prescribing profile?

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Are there differences in prescribing behavior

between urban and rural practices or between

small and large practices ?

Who are those prescribers who rapidly adopt to

recently released drugs ?

Can the factors that determine and change

prescribing behavior be identified ?

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E) Cost based informations

It will always be important in managing policy

related to drug supply, pricing and use.

E.g. Use of antipsychotic drugs in Australia

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The DUS cycle:

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Planning

Data collection

Evaluation

Feedback of results

Interventions

Reevaluation

Feedback of results

Steps involved in

conducting a drug

utilization study:-

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Step 1:- Identify drugs or therapeutic

areas of practice for inclusion in the

program

Drug-use Chain

a) The systems and structures surrounding drug use

e.g. how drugs are ordered, delivered and administered in a hospital or health care facility

b) The processes of drug use

e.g. what drugs are used and how they are used and does their use comply with the relevant criteria, guidelines or restrictions

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c) The outcome of drug use

e.g. efficacy, adverse drug reactions and the use of

resources such as drugs, laboratory tests, hospital

beds or procedures.

Drug utilization studies can be targeted towards any

of the above links in the drug use chain.

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Generally drugs with a high volume of use, high cost orhigh frequency of adverse drug reactions are subjected to DU studies

Common targets:-

Commonly prescribed drugs e.g. Antibiotics, PPIs, etc.

Drugs with significant drug interactions e.g. Warfarin, Phenytoin

Expensive drugs e.g. LMWH, Cephalosporins

Newer drugs

Drugs with a narrow therapeutic index e.g. Digoxin, Theophylline, Lithium

Drugs with serious ADRs e.g. aminoglycoside, NSAIDs etc.

Drugs in high risk patients e.g. elderly, pediatric patients

Drugs in the management of common conditions e.g. RTI or UTI, HTN, T2DM etc

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Step 2:- Design of study

In designing the DU study, observational research methods

are more commonly used.

Accordingly, DU study can be

Either :-

• Quantitative

• Qualitative

Or :-

Cross-sectional

Longitudinal

Continuous longitudinal

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Quantitative:-

Used to describe present situation and the trends in the

drug prescription and drug use at various levels of the

health care system.

Qualitative:-

Assess the appropriateness of drug utilization and link

the prescribing data to reasons for prescribing. It can be

referred as Drug Utilization Review or Drug Utilization

Evaluation. This process is one of the

therapeutic/prescription audit.

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Cross sectional studies-

Provide a snapshot of drug use at a particular time like

over a year, a month or a day

Used for making comparisons with similar data

collected over the same period in a different country,

health facility or a ward

Can be carried out before and after an intervention

Studies can simply measure drug use, or can be utilized

to assess drug use in relation to guidelines

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Longitudinal studies-

Data can be on total drug use or on a statistically valid

samples from pharmacies or medical practices.

Often obtained from repeated cross sectional surveys.

Data collection is continuous but the practitioner surveyed

and therefore patients are continuously changing.

Such data gives information about overall trends but not

about prescribing trends.

Provide information about concordance with treatment

based on the period between prescriptions, duration of

treatment, PDD etc

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Continuous longitudinal study-

◦ This data can address a range of issues

including reasons for change in therapy,

adverse effects and health outcomes

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Step 3:- Define criteria and

standards

With an exhaustive literature search, identify the

key literature in the chosen area of interest and

the drug criteria that can be derived from this

evidence based literature.

Must be valid, unambiguous, realistic, easily

measured and outcome oriented.

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Step 4:- Design the data collection form

◦ Patient demographics

◦ Prescriber details

◦ Indication/ Contraindications

◦ Side/adverse effects

◦ Dosing information

◦ Drug or drug class duplication

◦ Drug interactions

◦ Monitoring of drug therapy

◦ Patient education/instructions

◦ Cost of therapy

It is impossible to address all aspects of use for each

individual drug BUT

It is important to limit data collection to only the most

important and relevant aspects of drug use

Aspects of drug use commonly surveyed are -

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Step 5:- Data collection

Physicians, pharmacists and nurses make

ideal data collectors.

Different types of drug use information

are required depending upon the problem

being examined.

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Source of data

◦ Large databases

◦ Data from drug regulatory agency

◦ Supplier (distribution) data

◦ Practice setting data

◦ Community setting data

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Large databases:-

◦ Efficient use of health care resources - Computer

databases or medical record sections

◦ May be international, national or local- comparative

studies can be planned at various levels.

◦ May be diagnosis linked or non-diagnosis linked

◦ Diagnosis linked data enable drug use to be

analyzed according to patients characteristics,

therapeutic groups, diseases or conditions and,

clinical outcome.

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Data from drug regulatory agencies:-

Are repositories of data on which drugs have been

registered for use, withdrawn or banned within a

country.

Agencies have the legal responsibility of ensuring the

availability of safe, efficacious and good quality drugs

Possible to obtain data on the number of drugs

registered in a country from such agencies.

Importation data like product type (i.e. generic or

branded), volume, port of origin, country of

manufacture, batch number and expiry date may be

collected.

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Supplier (distribution) data:-

Drug importation; local manufacture; customs

service, whole salers

In countries where licenses are required from drug

regulatory authorities before importation of drugs

Generally be used to describe total quantities of

specific drug or drug group, origins of supplies

and type (i.e. branded or generic)

Distribution at different levels of supplies can be

compared

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Practice setting data:-

Generate indicators that provide information on

prescribing habits and aspects of patient care.

Prescribing data

Dispensing data

Aggregate (facility) data

Over-the-counter and pharmacist-prescribed drugs

Telephone and internet prescribing

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Prescribing data:

◦ Usually extracted from outpatient and inpatient prescriptions.

◦ Information that may be obtained from prescriptions includes

Patient’s demography

Drug name, dosage form, strength, dose, frequency of administration and duration of treatment.

Where diagnoses are noted on prescriptions, is possible to link drug use to indications.

Trends in utilization for specific drugs and diseases can also be established.

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Dispensing data:-Drug dispensing is a process that ends with a client

leaving a drug outlet with a defined quantity of medication and instructions for using it.

◦ Information available from dispensers may include

Drug (s) prescribed

Dose(s) prescribed

Average number of items per prescription

Percentage of items prescribed that were actually supplied (an indicator of availability)

Percentage of drugs adequately labeled

Quantity of medications dispensed

Cost of each item or prescription.

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Aggregate data

◦ Source include – pharmacy stock and dispensing

records, medication error records, adverse drug reaction

records and patient medical records.

◦ Used to obtain information on

The cost of individual drugs and classes of drug

The most and least expensive drugs

The per capita consumption of specific products.

The prevalence of adverse drug reactions.

The prevalence of medication errors.

The percentage of the budget spent on specific drugs

or classes of drug.

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Over-the-counter and pharmacist-

prescribed drugs:

◦ Pharmacists and other drug outlet managers may

prescribe over the counter (OTC) preparations or

pharmacist prepared drugs that do not require

prescription by physician.

◦ When such information is available from stock or

dispensing records, it broadens the understanding of

drug utilization patterns.

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Telephone and Internet prescribing:

Mostly in developed countries.

Innovative ways need to be devised to collect

information on this type of transaction.

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Community setting data:-

Drugs available in households have either been

prescribed or dispensed at health facilities,

purchased at pharmacy or are over the counter

medications.

The drugs may be for the treatment of current

illness or are left over from previous illness.

Data can be collected by performing household

surveys, counting left over pills etc.

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Step 6:- Evaluate results

Data evaluation is the most critical step in a DUS

Summarize data into the major categories of results

Check where exactly the data shows deviation from the

guidelines and usage criteria

Check whether true deviation exists

Evaluate reasons for this deviation

May be necessary to redefine the criteria

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Reasons for deviation may include:

◦ Drug being used for new indication

◦ Outdated procedures

◦ Inadequate resources

◦ Gaps in knowledge or misinformation /

misunderstanding

Evaluation is done with the help of:-

Drug Utilization Metrics

Drug Use Indicators

Drug classification systems

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Drug utilization metrics include:-

Defined daily dose

Prescribed daily dose

Other units for presentation of volume

Cost

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Defined daily dose (DDD):-

The DDD is the assumed average maintenance dose per

day for a drug used for its main indication in adults.

DDD is a unit of measurement and does not necessarily

correspond to the recommended or prescribed daily dose

(PDD).

Doses for individual patients and patient groups will

often differ from the DDD as they must be based on

individual characteristics (e.g. age and weight) and

pharmacokinetic considerations.

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It give a rough estimate of consumption and not an exact

picture of actual use.

DDDs provide a fixed unit of measurement independent

of price, currency, package size and strength enabling

the researcher to assess trends in drug consumption and

to perform comparisons between population groups.

Drug utilization figures should ideally be presented as

numbers of DDDs per 1000 inhabitants per day or,

when drug use by inpatients is considered, as DDDs per

100 bed-days.

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DDDs per 1000 inhabitants per day:-

◦ Provide a rough estimate of the proportion of the

study population treated daily with a particular drug or

group of drugs.

◦ E.g.-

10 DDDs per 1000 inhabitants per day indicates that 1%

of the population on average might receive a certain

drug or group of drugs daily.

◦ Most useful for chronically used drugs

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DDDs per inhabitant per year:-

◦ Estimate of the average number of days for which

each inhabitant is treated annually

E.g. -

◦ 5 DDDs per inhabitant per year indicates that the

utilization is equivalent to the treatment of every

inhabitant with a five-day course during a certain year.

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DDDs are not established for:-

◦ Topical products

◦ Sera, vaccines

◦ Antineoplastic agents

◦ Allergen extracts

◦ General and Local anesthetics

◦ Contrast media

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Prescribed daily dose (PDD):-

The prescribed daily dose (PDD) is defined as the

average dose prescribed according to a representative

sample of prescriptions.

Can be determined from studies of prescriptions or

medical or pharmacy records

Gives the average daily amount of a drug that is actually

prescribed

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The PDD can vary according to both the illness treated

and the national therapeutic traditions.

The PDDs differ:

◦ Between countries and ethnic groups

◦ Between areas or health care facilities within

the same country

◦ For different indications of the same drug

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PDD does not necessarily reflect actual drug

utilization.

Specially designed studies including patient

interviews are required to measure actual drug

intake at the patient level (i.e. the consumed

daily dose).

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Other units for presentation of volume:

These units can be applied only when the use of a single

drug or of well defined combination product is evaluated.

Grams of active ingredient:-

◦ Drugs with low potency will account for a larger

fraction of the total than drugs with high potency

◦ Combined products may also contain different

amounts of active ingredients from plain products

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Number of tablets:-

◦ Counting numbers of tablets does not reflect the

variations in strengths of tablets, with the result that

low-strength preparations contribute relatively more

than high-strength preparations to the total numbers

Numbers of prescriptions:-

◦ Do not accurately reflect total use, unless total

quantities of drugs per prescription are also considered.

◦ Valuable in measuring the frequency of prescriptions

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Cost:-

◦ Cost figures are suitable for an overall analysis of

expenditure on drugs.

◦ International comparisons based on cost parameters

can be misleading and have limited value in the

evaluation of drug use.

◦ Difficulties in evaluation may be due to

Price differences between alternative preparations

Fluctuations in currency

Changes in price

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Drug Use Indicators:-

Prescribing indicators

◦ Average number of drugs per encounter

◦ Percentage of drugs prescribed by generic name

◦ Percentage of encounters with an antibiotic prescribed

◦ Percentage of encounters with an injection prescribed

◦ Percentage of drugs prescribed from essential drugs

list or formulary

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Patient care indicators

◦ Average consultation time

◦ Average dispensing time

◦ Percentage of drugs actually dispensed

◦ Percentage of drugs adequately labelled

◦ Patients' knowledge of correct dosage

Facility indicators

◦ Availability of copy of essential drugs list or formulary

◦ Availability of key drugs

◦ Availability of clinical guidelines

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Complementary drug use indicators

o Average medicine cost per encounter

o Percentage prescriptions in accordance with clinical

guidelines

o Percentage of patients treated without drugs

o ** WHO-INRUD (International Network for the

Rational Use of Drugs) – WHO-1993

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Prescribing indicators:-

1. Average number of drugs per encounter

total number of different drug products prescribed

Average = --------------------------------------------------------------

number of encounters surveyed

2. Percentage (%) of drugs prescribed by generic name

number of drugs prescribed by generic name × 100

% = ---------------------------------------------------------------

total number of drugs prescribed

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3. Percentage of encounters with an antibiotic prescribed

4. Percentage of encounters with an injection prescribed

Number of patient encounters during which an antibiotic or an

injectable are prescribed x 100

% = -----------------------------------------------Total number of encounters surveyed

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5. Percentage of drugs prescribed from essential drugs list

or formulary

The number of products prescribed which are listed on the

essential drugs list or local formulary x 100

% = --------------------------------------------------

The total number of drugs prescribed

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Patient care indicators:-

1. Average consultation time

Total time for a series of consultation

Average=------------------------------------------------------

Number of consultations

2. Average dispensing time

Total time for dispensing drugs to a series of patients

Average=------------------------------------------------------

Number of encounters

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3. Percentage of drugs actually dispensed

number of drugs actually dispensed

at the health facility × 100

%= -------------------------------------------------------------

total number of drugs prescribed

4. Percentage of drugs adequately labeled

number of drug packages containing at least

patient name, drug name and when × 100

the drug should be taken

%= -----------------------------------------------------------------total number of drug packages dispensed

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5. Patients' knowledge of correct dosage

To reliably evaluate the correctness of patients'

responses about when they are to take the drugs, clear

guidelines should be developed about common dosage

regimens

number of patients who can adequately report the dosage

schedule for all the drugs x 100

%= --------------------------------------------------------------

total number of patients interviewed

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Facility indicators:-

1. Availability of copy of essential drugs list or formulary

2. Availability of clinical guidelines

◦ A national essential drugs list or a local formulary and a

clinical guideline must exist

◦ Scored as ‘Yes’ or ‘No’, per facility

3. Availability of key drugs

number of specified products actually in stock × 100

% = ----------------------------------------------------------------

total number of drugs on the checklist

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Model list of Key Drugs for testing drug

availability:-

Diarrhoea oral rehydration salts

cotrimoxazole tablets

Acute respiratory tract infections cotrimoxazole tablets

procaine penicillin injection

paediatric paracetamol tablets

Malaria chloroquine tablets

Anaemia ferrous salt + folic acid tablets

Worm infestations mebendazole tablets

Conjunctivitis tetracycline eye ointment

Skin disinfection iodine, gentian violet or local alternative

Fungal skin infection benzoic acid + salicylic acid ointment

Pain/fever acetylsalicylic acid or paracetamol tablets

Prophylactic drugs retinol (vitamin A)

ferrous salt + folic acid tablets

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Drug classification system:-

The main purpose of having an

international standard is to be able to

compare data between countries.

Different classification systems : -

◦ Anatomical Therapeutic Chemical (ATC)

classification develop by Norwegian researchers.

serve as a tool for presenting drug utilization statistics

recommended by WHO for international comparisons

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◦ Anatomical Therapeutic (AT) classification developed by

the European Pharmaceutical Market Research

Association (EPhMRA)

The EPhMRA classification system is used worldwide

by IMS (International Marketing Services) for

providing market research statistics to the

pharmaceutical industry.

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Step 7:- Provide feedback of results

Prepare a scientific interpretation of the results rather than a value judgment.

Success of any DUS depends on feedback of results to prescribers, other hospital staffs involved in the study and to administrative heads.

The results can also be circulated to hospital staff via newsletters or the hospital’s academic meetings.

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Step 8:- Develop and implement

interventions

If a drug use problem is identified the next step is to consider how the problem can be addressed.

Interventions:-

◦ Educational - educational meetings, development of protocols, letters to individual physicians.

◦ Operational - modification of drug order forms, development of stringent drug use policy, manual or computerized reminders, prescribing restrictions, formulary additions/deletions etc.

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Step 9:- Re-evaluate to determine

if drug use has improved

Drug use and prescribing patterns need to be

monitored to determine the success of intervention

Re-evaluation is usually done 3-12 months after the

introduction of the intervention

Collection of data as in original DUS

Should be a continuous process at regular interval

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Step 10:- Re-assess and revise the

DUS program

Results of the previous DU studies help to

improve quality, efficacy and effectiveness

of future DU studies.

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Step 11:- Feedback results

Circulate results of the DUS

Obtain opinions about success of interventions

and improvement of drug use.

Analyze and act accordingly

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DU 90%

Reflects the number of drugs that account for 90% of drug prescriptions and adherence to local or national prescription guidelines

Can be applied at different levels

◦ Individual prescriber

◦ Group of prescribers

◦ Wards

◦ Hospitals

◦ County

Gives a rough estimate of the quality of prescribing.

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Drug utilization evaluation

Drug utilization evaluation (DUE) is defined as an

authorized, structured, ongoing review of physician

prescribing, pharmacist dispensing and patient

using medication.

DUE is ongoing, systematic process designed to

maintain the appropriate and effective use of drugs

Synonymous- Drug Utilization Review (DUR)

Medication use evaluation (MUE) is similar to

DUE but emphasizes on improving patient’s clinical

outcome and individual quality of life.

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Objectives of DUE:-

To ensure that drug therapy meets current

standards of care

To control drug costs

To prevent problem related to medication, ADRs

To evaluate effectiveness of drug therapy

To identify areas of practice that require further

education of practitioners.

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Classification of DUE:

A) Prospective DUE:-

◦ Involves evaluating a patient’s planned drug therapy

before a medication is dispensed.

◦ Pharmacists perform prospective reviews by assessing

prescription medication’s dosage and it’s directions

and reviewing patient information for possible drug

interactions or duplication of therapy.

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Typical criteria reviewed in prospective studies include the following:-

Indications

Drug selection

Doses prescribed

Dosage form and routes of administration

Duration of therapy

Costs

Therapeutic duplication

Quantity dispensed

Contraindications

Therapeutic outcomes

Adverse drug reactions and drug interactions

Generic substitution

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B) Concurrent DUE:-

◦ Performed during the course of treatment and involves ongoing monitoring of drug therapy to ensure positive patient outcomes.

Typical criteria reviewed:-◦ Drug interactions

◦ High or low dosages

◦ Duplicate therapy

◦ Drug-disease interaction

◦ Over and under utilization

◦ Drug-age precautions

◦ Drug-gender precautions

◦ Drug-pregnancy precautions

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C) Retrospective DUE :-

◦ Simplest to perform since drug therapy is

reviewed after the patient has received

medication.

◦ Patients medical chart or computerized

records are screened to determine whether the

drug therapy met approved criteria.

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In retrospective studies, the criteria reviewed include:-

Evaluation of indications and contra-indications

Monitoring high cost medicines

Comparison of prescribing between physicians

Cost to patient

Over and under utilization

Incorrect drug dosage

Inappropriate duration

Adverse drug reaction

Drug interactions

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Statistical application in Drug

utilization research:-

Statistical Package for social science (SPSS) can be

used.

Chi square test can be used to test the difference

between the proportions.

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Future Perspectives:

The study of drug utilization in an evolving field.

The use of large computerized databases that allow

linkage of drug utilization data to diagnosis, subject to

some inherent limitations, is contributing to expand this

area of study.

Importance of drug utilization studies in

pharmacoepidemiology has been increasing due to their

close association to other areas like- public health,

pharmacovigilance, pharmacoeconomics and

pharmacogenetics

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Conclusion:-

Successful research in drug utilization requires multidisciplinary collaboration between clinicians, clinical pharmacologists, pharmacists and epidemiologists.

Without the support of the prescribers, this research effort will fail to reach its goal of facilitating the rational use of drugs.

Only by a combination of regulatory, informative and educational actions, together with a general improvement of the quality of in and out-patient medical care in the National Health System, the use of drugs can be more rational.

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