In evaluating a patient’s CYP2D6 phenotype before prescribing a drug with a narrow therapeutic window, which of the following represents the most critical clinical concerns?

Question

BlackTom AI · Accepted Answer

Question restatement: The prompt asks, when evaluating a patient’s CYP2D6 phenotype prior to prescribing a drug with a narrow therapeutic window, which option represents the most critical clinical concerns?

Option by option analysis:

Option 1: 'All of the above' — This choice suggests that all listed concerns are important. Given the context of a drug with a narrow therapeutic window and CYP2D6 phenotype variability, it makes sense that multiple cardiovascular, neurological, or other organ-specific adverse effects could arise if the metabolism is not properly accounted for. Therefore, this option is consistent with the overall clinical aim of balancing safety and efficacy by considering multiple facets of metabolism and response.

Option 2: 'Preventing adverse reactions in ultra-rapid metabolizers' — In ultra-rapid metabolizers, the drug may be cleared too quickly, potentially reducing efficacy or failing to achieve therapeutic concentrations, which can lead to treatment failure or the need for higher doses. This is a valid concern when a drug relies on CYP2D6 for activation or clearance, especially with a narrow therapeutic window where small changes in exposure can be clinically meaningful. The concern here is real and must be addressed in clinical planning.

Option 3: 'Avoiding inadequate drug response in poor metabolizers' — Conversely, poor metabolizers may have slower clearance or reduced activation (depending on whether the drug is a prodrug or active drug), leading to higher exposure, more adverse effects, or, if the drug requires activation, insufficient therapeutic effect. With a narrow therapeutic window, the line between efficacy and toxicity is tight, so avoiding under-response in poor metabolizers is a crucial consideration.

Option 4: 'Ensuring both safety and efficacy by tailoring the dose' — Personalizing dosing based on CYP2D6 phenotype aims to optimize therapeutic outcomes by achieving adequate drug exposure while minimizing toxicity. This encapsulates the overarching principle of pharmacogenomics in drugs with narrow therapeutic windows: tailor dose to phenotype to maintain safety and efficacy.

Synthesis and reasoning about all options:

- If we consider only one of the concerns (e.g., only ultra-rapid metabolizers or only poor metabolizers), we might miss risks on the opposite end of the metabolic spectrum. In a drug with a narrow therapeutic window, both ends of the metabolic spectrum can produce clinically meaningful deviations in exposure.
- The concern about tailoring dose integrates the need to balance efficacy (enough drug activity) with safety (avoiding excessive exposure and toxicity), which is particularly important in CYP2D6-affected metabolism where genotype can drastically alter pharmacokinetics.
- Therefore, each of options 2, 3, and 4 captures a distinct but interconnected facet of managing pharmacogenomic risk, and option 1 asserts that all are relevant.

Common misconceptions to watch for:

- Assuming a drug's activity is unaffected by CYP2D6 phenotype. This would ignore the potential for both under-treatment and overdose in different metabolizer groups.
- Believing only one metabolizer phenotype is clinically important. Narrow therapeutic windows amplify the consequences of both too-rapid and too-slow metabolism.
- Thinking dose tailoring is optional. In pharmacogenomics-informed practice, dosing adjustments are a central strategy to achieve safety and efficacy.

In summary, the reasoning supports the idea that all these concerns are critical components of evaluating CYP2D6 phenotype for a drug with a narrow therapeutic window, which aligns with choosing 'All of the above' as the most comprehensive and prudent stance.

PCOL2021 2025 Practice MCQ Section A - 2025

In evaluating a patient’s CYP2D6 phenotype before prescribing a drug with a narrow therapeutic window, which of the following represents the most critical clinical concerns?

View Explanation

Log in for full answers

Similar Questions

Evaluate the implications of pharmacogenomic variations in metabolizing enzymes when designing a clinical trial for a new cardiovascular drug.

How can genetic variation in HLA antigens influence drug therapy outcomes?

When considering the variability of drug metabolism among different geographical ancestries, which factor is most relevant for optimizing patient-specific therapy?

Which factor is NOT typically influenced by genetic variations in pharmacogenomics?

Evaluate the importance of integrating pharmacogenomic considerations into global drug development strategies.

What role do drug transporters play in pharmacogenomics?

In a consumer society, many adults channel creativity into buying things

More Practical Tools for Students Powered by AI Study Helper

Homework AI Solver

Stylized AI Paper Writer

Plagiarism Checker Assistant

Citation AI Academic Writing Tool

In-Class Translation Assistant

AI Note Generator

AI Quiz Answers

Past Exam Questions from University Test Bank

Smart Practice Assistant

Adaptive Practice

Making Your Study Simpler