Rationale for drug therapy and evidence based medicine MCQs With Answer

Introduction:
This collection of MCQs on Rationale for Drug Therapy and Evidence-Based Medicine is designed for M.Pharm students preparing for Pharmacotherapeutics I (MPP 102T). The set emphasizes clinical decision-making principles, therapeutic rationale, and the critical appraisal of clinical research. Questions cover drug selection criteria, benefit–risk assessment, biomarkers and surrogate endpoints, combination therapy rationale, and patient-centered considerations. Evidence-based medicine topics include study designs, bias types, randomization principles, interpretation of confidence intervals, NNT/NNH calculations, meta-analysis concepts, and guideline implementation using grading systems like GRADE. Use these items to strengthen conceptual understanding and enhance application of evidence into rational therapeutic choices.

Q1. Which principle best describes the main rationale for choosing a drug with a high therapeutic index in chronic therapy?

• To maximize receptor occupancy regardless of adverse effects
• To ensure a wide margin between effective and toxic doses
• To minimize dosing frequency even if toxicity risk increases
• To select the most expensive drug available

Correct Answer: To ensure a wide margin between effective and toxic doses

Q2. In evidence-based medicine, which of the following most accurately defines the term “number needed to treat (NNT)”?

• The number of patients needed to be treated for one to experience an adverse event
• The reciprocal of the absolute risk reduction representing patients treated to prevent one event
• The number of subjects randomized in a clinical trial
• The ratio of relative risk reduction to baseline risk

Correct Answer: The reciprocal of the absolute risk reduction representing patients treated to prevent one event

Q3. Which study design provides the highest level of evidence for causality when assessing drug efficacy?

• Case-control study
• Cohort study
• Randomized controlled trial
• Cross-sectional survey

Correct Answer: Randomized controlled trial

Q4. When critically appraising a randomized trial, which bias is best controlled by blinding outcome assessors?

• Selection bias
• Performance bias
• Detection bias
• Attrition bias

Correct Answer: Detection bias

Q5. Which element is NOT part of the three pillars of evidence-based medicine?

• Best available external clinical evidence
• Patient values and preferences
• Clinical expertise
• Pharmaceutical marketing recommendations

Correct Answer: Pharmaceutical marketing recommendations

Q6. A meta-analysis reports a pooled risk ratio of 0.78 with a 95% confidence interval 0.62–0.98. What is the most appropriate interpretation?

• The treatment has no effect because the CI includes 1
• The treatment is associated with a statistically significant risk reduction
• The treatment effect is clinically irrelevant despite statistical significance
• There is severe heterogeneity preventing any conclusion

Correct Answer: The treatment is associated with a statistically significant risk reduction

Q7. Which scenario best justifies use of a surrogate endpoint in drug development?

• When the clinical endpoint is rapidly measurable and inexpensive
• When surrogate reliably predicts meaningful clinical outcomes and shortens trial duration
• When regulators do not accept surrogate measures
• When no biological rationale links surrogate to clinical outcome

Correct Answer: When surrogate reliably predicts meaningful clinical outcomes and shortens trial duration

Q8. In designing a superiority RCT, which factor primarily determines the required sample size?

• Number of study sites
• Expected effect size, alpha, and power
• Duration of follow-up alone
• Price of the investigational drug

Correct Answer: Expected effect size, alpha, and power

Q9. Which grading system is commonly used to rate quality of evidence and strength of recommendations in clinical guidelines?

• Cochrane Risk of Bias tool
• GRADE (Grading of Recommendations, Assessment, Development and Evaluation)
• CONSORT checklist
• STROBE statement

Correct Answer: GRADE (Grading of Recommendations, Assessment, Development and Evaluation)

Q10. A trial analyzed results by intention-to-treat (ITT). What is the main advantage of ITT analysis?

• It excludes non-compliant patients to show true efficacy
• It preserves benefits of randomization and avoids attrition bias
• It only includes patients who completed the treatment per protocol
• It inflates the apparent treatment effect for publication

Correct Answer: It preserves benefits of randomization and avoids attrition bias

Q11. Which of the following best describes publication bias in evidence synthesis?

• Preferential publication of studies with positive results, skewing meta-analytic estimates
• Bias introduced by poor randomization
• Selective outcome reporting within a published trial only
• Bias from measuring outcomes with unreliable instruments

Correct Answer: Preferential publication of studies with positive results, skewing meta-analytic estimates

Q12. In benefit–risk assessment for a new antihypertensive, which quantitative metric directly compares harms and benefits?

• Number Needed to Treat (NNT) compared with Number Needed to Harm (NNH)
• Relative risk without baseline risk context
• P-value of blood pressure reduction
• Hazard ratio alone

Correct Answer: Number Needed to Treat (NNT) compared with Number Needed to Harm (NNH)

Q13. Which of the following indicates high heterogeneity among studies in a meta-analysis?

• I-squared (I2) = 5%
• I-squared (I2) = 40%
• I-squared (I2) = 75%
• I-squared (I2) = 0%

Correct Answer: I-squared (I2) = 75%

Q14. For individualized drug therapy, therapeutic drug monitoring (TDM) is most valuable when:

• There is a wide therapeutic index and linear kinetics
• There is a narrow therapeutic index and clear concentration–response relationship
• Drug effect cannot be measured clinically
• Drug is always dosed once daily without variability

Correct Answer: There is a narrow therapeutic index and clear concentration–response relationship

Q15. Which CONSORT item is essential to assess the internal validity of a randomized trial report?

• Detailed pharmacokinetic data for all participants
• Flow diagram of participant enrollment, allocation, follow-up, and analysis
• Marketing strategy for the investigational drug
• Historical background of the disease only

Correct Answer: Flow diagram of participant enrollment, allocation, follow-up, and analysis

Q16. A subgroup analysis reports benefit only in elderly patients. What is the most cautious interpretation?

• Accept subgroup finding as definitive without further testing
• Consider it hypothesis-generating and verify in pre-specified analyses or new studies
• Ignore age effects since subgroups are always unreliable
• Assume the drug is harmful in younger patients

Correct Answer: Consider it hypothesis-generating and verify in pre-specified analyses or new studies

Q17. Which measure best describes precision of an effect estimate in a clinical trial?

• Mean difference alone
• Width of the 95% confidence interval
• P-value only
• Number of study centers

Correct Answer: Width of the 95% confidence interval

Q18. When integrating evidence into clinical practice guidelines, which factor besides evidence quality should be explicitly considered?

• Availability and costs of interventions, patient values, and resource implications
• Only the opinion of the guideline chairperson
• Marketing authorizations in other countries without critical appraisal
• Duration of the guideline development process alone

Correct Answer: Availability and costs of interventions, patient values, and resource implications

Q19. Which type of bias occurs when loss to follow-up differs between randomized groups and relates to outcome?

• Selection bias
• Detection bias
• Attrition bias
• Performance bias

Correct Answer: Attrition bias

Q20. In a pragmatic clinical trial designed to inform routine practice, which characteristic is prioritized?

• Strict eligibility criteria and intensive monitoring
• High internal control with placebo-only comparisons
• Broad eligibility, flexible interventions, and outcomes relevant to everyday care
• Use of surrogate endpoints only

Correct Answer: Broad eligibility, flexible interventions, and outcomes relevant to everyday care

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