The drug effect is the quantifiable change in disease processes that result from the pharmacological or physical properties of an active treatment. To figure out the effectiveness of the drug, To check the toxicity of the drug  and to investigate if symptoms of a serious side effect is present evaluating a drug effect is essential.

1. EVALUATION OF DRUG
EFFECTS
RITHIKA. R.S | II M. SC. BIOINFORMATICS,
DEPARTMENT OF BIOINFORMATICS,
SRI KRISHNA ARTS AND SCIENCE COLLEGE, COIMBATORE.

2. DRUG EFFECT
The drug effect is the quantifiable change in disease processes that result from
the pharmacological or physical properties of an active treatment.
Difference between action and effect of drug:
◦ Actions of drugs are the biochemical physiological mechanisms by which the
chemical produces a response in living organisms.
◦ The effect is the observable consequence of a drug action.
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3. Why evaluation of drug effects???
 To figure out the effectiveness of the drug
 To check the toxicity of the drug
 If symptoms of a serious side effect is present
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4. Variations in drug effects…
Patient characteristics
1. Age
2. Gender
3. Ethnicity
4. Genetic Constitution
5. Food style/ Life style
6. Environment
7. Co-existing disorder
Drug factors
1. Type of drug
2. Route of administration
3. Treatment duration
4. Dosage
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5. Evaluation with existing knowledge
• Unlike beneficial effects adverse effects is vast, ranging from mild symptoms to fatal
events.
• Some adverse effects are predictable from the pharmacological properties and are
easily monitored while others are rather unusual.
• Based on past knowledge of recognized findings of drugs or a strong link with the
mechanism of action of the drug.
• Bradycardia with beta-blockers, and cardiac arrhythmias with amiodarone are very
well monitored in cardiovascular trials.
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6. Spontaneous reporting
 Distinct clinical features are likely to be captured through spontaneous
reporting, case reports or case series.
 Progressive multifocal leukoencephalopathy is a rare, severe viral infection
associated with certain biologic agents.
 Even non-severe, reversible events may be captured through spontaneous
reporting because of the distinctive features, such as corneal deposits with
amiodarone.
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7. Follow-up evaluation
 The purpose of the follow-up evaluation is to determine the patient's outcomes
 Both effectiveness and drug safety are evaluated
 Includes measurable improvement in clinical signs and symptoms and/or laboratory
values
 Includes evidence of adverse drug reactions and/or toxicity.
 In, follow-up evaluation is the step in which actual results and outcomes are
documented.
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8. Randomized Controlled Studies
 Evaluation in which the population receiving treatment is chosen at random from the eligible
population, and a control group is also chosen at random from the same eligible population.
 Myocardial infarction is common and expected in patients with diabetes, controlled clinical
data from RCTs and large pharmaco-epidemiological studies would be the most useful sources.
 Mild events which are typically seen in the general population (e.g. muscle ache with statins,
cough with angiotensin-converting enzyme [ACE] inhibitors) are Likely to be detected in
Randomized Controlled Studies that rely on pharmaco-epidemiological databases of hospital
admissions.
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9. Time of study
 The timing of the studies are also crucial as the detection and reporting of a
particular adverse event may increase exponentially as the suspicion with a
new signal grows with time.
 For example, the cardiovascular adverse effects of thiazolidinediones, earlier
trials has not have provided any adverse effects data, but after subsequent trials
have yielded much more data.
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10. Case – Control study
 A study that compares two groups of people: those with the disease or
condition under study (cases) and a very similar group of people who do not
have the disease or condition (controls).
 Case-Control study design is a type of observational study.
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11. Quantitative analysis
For quantitative analysis of relative risk, we need to consider three key aspects:
1. Typical background incidence of the adverse outcome in unexposed
patients,
2. Onset (timing) of event relative to drug exposure
3. Anticipated magnitude of increase in risk with the drug
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12. Meta analysis
 Meta-analysis is a quantitative, formal, epidemiological study design used to
systematically assess the results of previous research to derive conclusions about that
body of research.
 Typically, the study is based on randomized, controlled clinical trials.
 A method for systematically combining qualitative study data from several selected studies to
develop a single conclusion that has greater statistical power.
 This conclusion is statistically stronger than the analysis of any single study, due to increased
numbers of subjects.
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13. Data sources
Source Example
Product Information sheets UK ABPI electronic Medicines Compendium (eMC)
Regulatory authorities bulletins
and drug reviews
• Canadian Adverse Reaction Newsletter (CARN)
• Drug Safety Update (UK)
• FDA Medwatch
• Australian Medicines Safety
• Netherlands LAREB updates
• FDA Drug Approval
Pharmaceutical company study
registers
• Clinical Study Results Database,(http://www.clinicalstudyresults.org/ )
• International Federation of Pharmaceutical Manufacturers and Associations
(IFPMA) clinical trials portal, (clinicaltrials.ifpma.org/ )
• Lead Discovery (http://www.leaddiscovery.co.uk )
• GlaxoSmithKline clinical study register, (http://www.gsk-
clinicalstudyregister.com )
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14. Source Example
Spontaneous reporting • Adverse Drug Reactions Database
• Canada’s Adverse Drug Reaction Database,
• UK Yellow Card scheme: Drug Analysis Prints (DAPs), Netherlands LAREB,
http://www.lareb.nl/kennis/zoeksignalen.asp
• DIOGENES: Adverse Drug Events Database for data from the Food and Drug
Administration (FDA) US MedWatch service,
• PharmaPendium, FDA's Adverse Event Reporting System (AERS) and
Spontaneous Reporting System (SRS),
• Vigibase Services: Uppsala Monitoring Centre (WHO) collects individual
reports from 77 countries
Bibliographic databases TOXLINE (Toxicology Literature Online), MEDLINE, EMBASE, BIOSIS,
Derwent Drug File, International Pharmaceutical Abstracts (IPA), Iowa Drug
Information Service (IDIS), PASCAL, Science Citation Index (SCI)
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Data sources

15. References
1. Coleman JJ, Pontefract SK. Adverse drug reactions. Clin Med (Lond). 2016 Oct;16(5):481-
485. doi: 10.7861/clinmedicine.16-5-481. PMID: 27697815; PMCID: PMC6297296.
2. Loke YK, Golder SP, Vandenbroucke JP. Comprehensive evaluations of the adverse effects of
drugs: importance of appropriate study selection and data sources. Ther Adv Drug Saf. 2011
Apr;2(2):59-68. doi: 10.1177/2042098611401129. PMID: 25083202; PMCID: PMC4110807.
3. https://www.msdmanuals.com/en-in/professional/clinical-pharmacology/adverse-drug-
reactions/adverse-drug-reactions
4. https://accesspharmacy.mhmedical.com/content.aspx?bookid=491&sectionid=39674908
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16. DEPARTMENT OF BIOINFORMATICS, SKASC 16
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