Barriers And Interventions - NAPLEX

SECTION 1

Historical Context & Motivation

The recognition that patients frequently fail to achieve therapeutic goals is not a modern discovery—clinicians have grappled with barriers to optimal pharmacotherapy for centuries. In the earliest eras of organized medicine, physicians observed that patients did not always follow prescribed regimens, yet the systematic study of why and how these failures occur is largely a product of the twentieth century. As pharmacy practice evolved from a product-centered dispensing model to a patient-centered clinical discipline, the profession embraced the responsibility of identifying and resolving barriers that impede therapeutic success. The NAPLEX examination tests your ability to recognize these barriers and select appropriate, evidence-based interventions—skills that are essential for every practicing pharmacist.

1975 • Medication Adherence Research Begins

Sackett and Haynes publish landmark research defining and quantifying patient compliance, establishing the field of adherence science and demonstrating that nearly 50% of patients do not take medications as prescribed.

1990 • Pharmaceutical Care Model Introduced

Hepler and Strand define pharmaceutical care as the responsible provision of drug therapy to achieve definite outcomes that improve quality of life, shifting pharmacy's focus toward identifying and resolving drug-related problems.

2003 • WHO Adherence Report

The World Health Organization publishes a comprehensive report on adherence to long-term therapies, identifying five interacting dimensions of barriers: social/economic, health system, condition-related, therapy-related, and patient-related factors.

2011 • MTM Services Codified in ACA

The Affordable Care Act formally integrates Medication Therapy Management (MTM) into Medicare Part D, requiring pharmacists to perform comprehensive medication reviews and intervene on identified barriers.

2020s • Health Equity & Social Determinants

National pharmacy organizations and accreditation bodies emphasize social determinants of health (SDOH) as critical barriers, embedding health equity into pharmacy education and the NAPLEX blueprint.

The central question this lesson addresses is both clinical and professional: How does a pharmacist systematically identify the barriers that prevent a patient from achieving therapeutic goals, and what interventions can be employed to overcome each barrier? Mastering this framework will prepare you not only for the NAPLEX but also for everyday practice, where resolving barriers is among the most impactful contributions a pharmacist makes to patient care.

SECTION 2

Core Principles & Definitions

Before diving into specific barrier categories and interventions, it is essential to establish a conceptual vocabulary. A barrier is any factor—patient-related, system-related, socioeconomic, or therapy-related—that impedes a patient from achieving the intended therapeutic outcome. An intervention is a purposeful action taken by the pharmacist (or interprofessional team) to eliminate, reduce, or work around a barrier. Person-centered care demands that interventions be tailored to the individual patient's values, preferences, and circumstances rather than applied as one-size-fits-all solutions.

Patient-Related Barriers

Health literacy deficits, cognitive impairment, lack of motivation, cultural beliefs, psychological conditions (depression, anxiety), and physical limitations (visual or dexterity impairments) that affect a patient's ability or willingness to follow a treatment plan.

Therapy-Related Barriers

Complex dosing regimens, adverse drug reactions, polypharmacy, drug–drug or drug–food interactions, formulation challenges (tablet size, taste), and long duration of therapy that diminish adherence or compromise efficacy.

Socioeconomic Barriers

High medication costs, lack of insurance, food insecurity, unstable housing, limited transportation, and employment constraints that prevent patients from accessing or affording prescribed therapies.

Health-System Barriers

Fragmented care among multiple providers, lack of care coordination, restricted formularies, prior authorization delays, inadequate follow-up mechanisms, and limited access to pharmacist-provided clinical services.

Condition-Related Barriers

Asymptomatic disease states (e.g., hypertension, hyperlipidemia), fluctuating severity, comorbidities that compete for attention, and the chronic nature of illness which can lead to treatment fatigue over time.

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KEY TAKEAWAY

Think of the patient's treatment plan as a river flowing toward a destination (the therapeutic goal). Barriers are dams, rocks, and diversions that block or redirect the flow. The pharmacist's job is to survey the entire riverbed—not just the most visible dam—and deploy the right tools (interventions) at the right points to restore the flow. A patient who cannot afford a medication and also does not understand why it was prescribed faces two distinct barriers, each requiring its own targeted intervention.

SECTION 3

Visual Explanation — The Barrier–Intervention Framework

The framework illustrates the patient's journey from prescription to therapeutic goal. Barrier categories (patient, therapy, socioeconomic, health system) appear as obstacles along the pathway, and each maps via dashed lines to a corresponding set of intervention strategies that collectively drive the patient toward improved outcomes.

As the diagram above illustrates, the pharmacist should conceptualize the patient's therapeutic journey as a linear pathway interrupted by multiple potential barriers. Notice that the patient-related and therapy-related barriers occupy positions closest to the prescription origin, because these are often the first obstacles encountered. Socioeconomic and health-system barriers tend to manifest further downstream—at the point of fill, during follow-up, or across transitions of care. Effective person-centered treatment planning requires the pharmacist to assess all four domains concurrently rather than addressing only the most obvious barrier.

SECTION 4

How Barrier Identification Works in Practice

The Assess–Identify–Intervene–Monitor Cycle

Person-centered barrier resolution follows a cyclical process that mirrors the pharmacist's patient care process (PPCP) endorsed by JCPP. The cycle begins with a comprehensive assessment of the patient's medical, social, and medication history. During this phase, the pharmacist uses open-ended questions, validated screening tools, and clinical observation to surface potential barriers. The identification phase classifies each barrier according to the five-domain model (patient, therapy, socioeconomic, health-system, condition-related) so that the appropriate category of interventions can be matched. The intervention phase implements one or more targeted strategies, and finally the monitoring phase evaluates whether the barrier has been resolved and the patient is progressing toward the therapeutic goal. If the barrier persists, the cycle repeats with an adjusted approach.

Common Assessment Tools

Tool / Technique	Barrier Domain Assessed	Description
Morisky Medication Adherence Scale (MMAS-8)	Patient-related	Eight-item self-report questionnaire measuring intentional and unintentional non-adherence
Teach-Back Method	Patient-related (literacy)	Ask the patient to explain instructions in their own words to confirm understanding
Medication Possession Ratio (MPR)	Multiple domains	Ratio of days supply obtained to days in evaluation period; MPR ≥ 0.80 considered adherent
PRAPARE Screening Tool	Socioeconomic (SDOH)	Standardized social determinants screening covering housing, food, transportation, and social support
Motivational Interviewing	Patient-related (motivation)	Collaborative communication style that strengthens intrinsic motivation and commitment to change

Assessment tools commonly used by pharmacists to identify barriers

Quantifying Adherence

MEDICATION POSSESSION RATIO

MPR = (Total Days Supply Dispensed ÷ Number of Days in Evaluation Period) × 100%

An MPR ≥ 80% is the conventional threshold for adequate adherence. Values below 80% flag a potential barrier requiring further investigation into the underlying cause.

PROPORTION OF DAYS COVERED

PDC = (Number of Days Covered ÷ Number of Days in Evaluation Period) × 100%

PDC is preferred by CMS quality measures because it adjusts for overlapping fills. Unlike MPR, PDC cannot exceed 100%. A PDC ≥ 80% is the benchmark for adherence in Star Ratings.

SECTION 5

Detailed Breakdown of Intervention Strategies

Matching the right intervention to the identified barrier is the pharmacist's core clinical skill in person-centered care. This section classifies interventions according to the barrier domain they address, though in practice many interventions span multiple domains. The following diagram organizes interventions into a tiered approach, from patient-level to system-level strategies.

The four-tier model organizes interventions from patient-level (education, motivation) through therapy-level (regimen changes, ADR management), socioeconomic (cost reduction, resource referral), and health-system (care coordination, policy navigation) strategies.

In clinical practice, patients frequently present with barriers spanning multiple tiers simultaneously. A patient newly discharged from the hospital, for example, may face confusion about new medications (Tier 1), a complex multi-drug regimen (Tier 2), inability to afford new prescriptions (Tier 3), and lack of scheduled follow-up (Tier 4). The pharmacist must triage barriers by urgency and impact, addressing the most critical barriers first while developing a comprehensive plan that touches all relevant tiers.

SECTION 6

Worked Example — Identifying Barriers and Selecting Interventions

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PATIENT SCENARIO

Mrs. Garcia is a 68-year-old Spanish-speaking woman with type 2 diabetes, hypertension, and hyperlipidemia. She presents for a comprehensive medication review (CMR). Her medication list includes metformin 1000 mg BID, lisinopril 20 mg daily, amlodipine 10 mg daily, atorvastatin 40 mg daily, and insulin glargine 30 units at bedtime. Her most recent A1C is 9.2% (goal <7%), blood pressure is 148/92 mmHg, and LDL is 118 mg/dL. Refill records show an MPR of 62% for metformin and 45% for insulin glargine. She states she sometimes forgets her evening medications and that the insulin costs too much.

Step-by-Step Barrier Identification and Intervention Planning

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Step 1 — Gather and Organize Data

Review the patient's medical conditions (DM2, HTN, HLD), current medications, laboratory values, and adherence metrics. Calculate PDC or review MPR: metformin MPR = 62% and insulin MPR = 45%, both well below the 80% adherence threshold. Her A1C of 9.2% and BP of 148/92 mmHg confirm she is not at goal for two of three conditions.

Key finding: Significant non-adherence to metformin and insulin glargine; all three conditions suboptimally controlled.
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Step 2 — Identify Barriers by Domain

Through the CMR interview (using open-ended questions and the teach-back method), the pharmacist uncovers four distinct barriers. Patient-related: Mrs. Garcia has limited English proficiency and does not fully understand her insulin dosing instructions. Therapy-related: She takes five medications across multiple dosing times (BID + daily + bedtime), leading to forgetfulness for evening doses. Socioeconomic: She reports that insulin glargine costs $150 per month out of pocket, which she cannot consistently afford on a fixed income. Condition-related: Hypertension and hyperlipidemia are asymptomatic, reducing her perceived need for those medications.

Four barriers identified: language/literacy, regimen complexity, medication cost, asymptomatic disease.
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Step 3 — Prioritize Barriers by Clinical Impact

The insulin non-adherence (MPR 45%) is the most clinically urgent barrier because uncontrolled diabetes (A1C 9.2%) poses the greatest near-term risk for complications. The cost barrier directly drives this non-adherence, so addressing cost is the highest-priority intervention. The language barrier also contributes to insulin misuse, making it the second priority. Regimen complexity and asymptomatic disease perception are secondary but still require attention.

Priority order: (1) Insulin cost, (2) Language/understanding, (3) Regimen complexity, (4) Disease perception.
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Step 4 — Select Targeted Interventions

For the cost barrier: recommend switching to a biosimilar insulin glargine (e.g., Semglee) or enrolling in a manufacturer patient assistance program; also consider the Inflation Reduction Act's $35/month insulin cap if she has Medicare Part D. For the language barrier: provide counseling in Spanish (or via interpreter services), supply written materials in Spanish, and use the teach-back method to verify comprehension. For regimen complexity: recommend a pill organizer, consolidate dosing times where possible (e.g., switch metformin to ER 2000 mg once daily), and set phone alarms. For asymptomatic disease perception: use motivational interviewing to explore her understanding of long-term cardiovascular risk and connect treatment to personal goals (e.g., staying healthy for grandchildren).

Interventions: Biosimilar switch/PAP enrollment, Spanish-language counseling, regimen simplification (metformin ER), motivational interviewing.
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Step 5 — Document and Monitor

Document all identified barriers and planned interventions in the patient's medication action plan (MAP) as part of the CMR. Schedule a follow-up call in 2–4 weeks to reassess MPR, verify insulin affordability, confirm the patient can demonstrate correct injection technique in Spanish, and recheck blood pressure at next clinic visit. If barriers persist, the cycle restarts with modified interventions.

Outcome: Documented MAP with timeline for reassessment; goal is MPR ≥ 80% for all medications and A1C < 7% within 3–6 months.

SECTION 7

Strengths and Limitations of Common Interventions

No single intervention is universally effective for all patients or all barrier types. Understanding the strengths and limitations of each strategy enables the pharmacist to select the most appropriate approach—or, more commonly, to combine multiple interventions for maximum impact. The following table compares the most frequently employed interventions across several dimensions relevant to NAPLEX preparation and clinical practice.

Intervention	Strengths	Limitations
Patient Education / Counseling	Directly addresses knowledge gaps; can be tailored to literacy level; immediate and low-cost to implement at point of care	Effectiveness depends on pharmacist communication skills; one-time counseling may not sustain behavior change; limited impact if cost or access is the true barrier
Motivational Interviewing	Evidence-based approach for ambivalence; respects patient autonomy; builds therapeutic alliance and long-term engagement	Requires specialized training; time-intensive; may not resolve structural barriers (cost, system issues)
Regimen Simplification	Strong evidence for improving adherence; reduces pill burden and dosing errors; may improve tolerability	Not always clinically feasible; combination products may cost more; some conditions require complex regimens
Generic / Therapeutic Substitution	Significant cost savings; pharmacist can often implement independently under state substitution laws	Not available for all brand medications; patient may have tried and failed generic; narrow therapeutic index drugs require caution
MTM / CMR Services	Comprehensive; addresses multiple barriers simultaneously; reimbursable under Medicare Part D; improves clinical outcomes in RCTs	Eligibility criteria limit reach; requires documentation infrastructure; follow-up rates vary; not all patients are engaged
Patient Assistance Programs (PAPs)	Can eliminate out-of-pocket costs entirely; available for many brand-name and specialty drugs	Application process can be complex; income eligibility varies; delays in enrollment; may not cover all medications

Comparison of common pharmacist-led interventions

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KEY TAKEAWAY

Think of intervention selection like a diagnostic process in itself: just as prescribing the wrong antibiotic for a given organism leads to treatment failure, applying the wrong intervention to a misidentified barrier will not improve outcomes. A patient who cannot afford her insulin does not primarily need more education—she needs financial access first. The pharmacist's value lies in accurate barrier diagnosis followed by targeted intervention prescription.

SECTION 8

Connection to Advanced Practice & Emerging Trends

As pharmacy practice evolves, the framework of barriers and interventions is expanding to incorporate technology, precision medicine, and health equity science. Understanding these connections positions you not only for NAPLEX success but also for advanced clinical roles. The table below contrasts the foundational concepts covered in this lesson with the emerging directions that represent the future of person-centered pharmacotherapy.

Foundational Concept	Advanced / Emerging Direction
Self-reported adherence (MMAS-8)	Smart pill bottles, digital health platforms, and electronic pill caps (MEMS) that provide objective, real-time adherence data
Generic substitution for cost	Value-based insurance design (VBID), outcomes-based contracts, and transparent drug pricing models
One-size-fits-all education	Pharmacogenomic-guided counseling, tailoring education based on genetic metabolizer status and expected ADR profiles
SDOH screening (PRAPARE)	Health equity dashboards, geospatial analytics identifying pharmacy deserts, and community health worker integration
MTM during Medicare Part D eligibility	Pharmacist provider status legislation, expanded scope under collaborative practice agreements, and reimbursement parity for cognitive services

Foundational vs. emerging approaches to barriers and interventions

The trajectory of pharmacy practice is moving toward increasingly proactive, data-driven, and equity-conscious barrier resolution. Emerging technologies like artificial intelligence-powered medication synchronization and pharmacogenomic decision support will allow pharmacists to anticipate barriers before they manifest, rather than reacting after therapeutic failure has occurred. Regardless of technological advances, the fundamental principle remains: the pharmacist must understand the whole patient to deliver truly person-centered care.

SECTION 9

Practice Problems

Question 1: CONCEPTUAL

A patient with well-controlled hypertension on amlodipine 5 mg daily tells the pharmacist, 'I feel fine, so I stopped taking my blood pressure pill last week.' Which barrier domain best describes this situation, and what makes it different from a patient who simply forgets to take the medication?

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This represents a condition-related barrier rooted in the asymptomatic nature of controlled hypertension. The patient has made a deliberate decision to discontinue therapy because they perceive no benefit ('I feel fine'), which constitutes intentional non-adherence. This differs from forgetting (unintentional non-adherence), which is a patient-related barrier typically addressed with reminders and adherence aids. Intentional non-adherence related to asymptomatic disease requires motivational interviewing and patient education about the long-term consequences of uncontrolled hypertension, such as stroke and kidney damage, rather than pill organizers or alarms.

Question 2: BASIC CALCULATION

A patient filled a 30-day supply of lisinopril on January 1, January 28, March 5, and April 2. Calculate the Medication Possession Ratio (MPR) over the 120-day period from January 1 through April 30. Is this patient considered adherent?

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Total days supply dispensed = 4 fills × 30 days = 120 days. The evaluation period is January 1 through April 30 = 120 days. MPR = (120 ÷ 120) × 100% = 100%. However, note the gap between the second fill (January 28) and third fill (March 5)—a 36-day interval for a 30-day supply, indicating 6 days without medication. While MPR appears adequate because total days supply equals the evaluation period, PDC would reveal the coverage gap. Nevertheless, using the MPR threshold of ≥ 80%, this patient is classified as adherent by MPR.

Question 3: INTERMEDIATE

A 55-year-old patient with type 2 diabetes, depression, and chronic pain is taking metformin 500 mg TID, sertraline 100 mg daily, gabapentin 300 mg TID, lisinopril 10 mg daily, and ibuprofen 400 mg TID PRN. His A1C is 8.5%. He reports GI side effects and says he often skips his metformin because of nausea. Identify at least three distinct barriers and propose a specific intervention for each.

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Barrier 1 (Therapy-related — ADR): GI side effects from metformin TID cause him to skip doses. Intervention: Recommend switching to metformin ER at an equivalent total daily dose (e.g., 1500 mg ER once daily), which reduces GI intolerance and simplifies the regimen. Barrier 2 (Therapy-related — Complexity): The patient is taking multiple TID medications. Intervention: Consolidate dosing by switching to extended-release formulations where possible and provide a medication schedule chart. Barrier 3 (Condition-related — Comorbidity): Depression can reduce motivation and self-care behaviors, including medication adherence. Intervention: Confirm sertraline is at therapeutic dose, screen for depression control (PHQ-9), and refer to prescriber for optimization if depression is uncontrolled. Additionally, the pharmacist should flag the ibuprofen–lisinopril interaction (reduced antihypertensive effect, renal risk) as a drug-related problem requiring resolution.

Question 4: APPLIED

You are a community pharmacist conducting an MTM session for a 72-year-old Medicare Part D patient with heart failure, atrial fibrillation, and COPD. During the CMR, you discover that the patient was discharged from the hospital 10 days ago with three new medications added to his existing eight-drug regimen. He lives alone, has no family nearby, and uses a transportation service to get to the pharmacy. His PDC for warfarin over the last 6 months is 58%. Design a comprehensive intervention plan addressing all identified barriers, prioritized by clinical urgency.

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The most clinically urgent barrier is the low warfarin adherence (PDC 58%) in a patient with atrial fibrillation, which places him at high risk for stroke. Priority 1: Perform a thorough transitions-of-care medication reconciliation comparing the hospital discharge list to current therapy to identify discrepancies. Recommend switching from warfarin to a DOAC (e.g., apixaban) if appropriate, which eliminates INR monitoring burden and may improve adherence—discuss with prescriber. Priority 2: Address polypharmacy (now 11 medications) by reviewing each medication for appropriateness, screening for drug–drug interactions, and deprescribing where clinically justified. Organize the regimen into a visual medication schedule. Priority 3: Address the transportation and social isolation barriers by enrolling the patient in mail-order pharmacy for 90-day supplies, coordinating med-sync so all refills align, and referring to a local Area Agency on Aging for additional social support services. Priority 4: Schedule a follow-up phone call within 7 days and coordinate with the patient's primary care provider and cardiologist to ensure shared awareness of the intervention plan. Document all findings and recommendations in the MAP.

Question 5: CRITICAL THINKING

A pharmacy director asks you to design a system-level quality improvement initiative to reduce 30-day readmission rates at your hospital by addressing medication-related barriers. Using the five-domain barrier model and evidence-based intervention strategies, outline a multi-component program. Discuss how you would measure success, anticipate potential challenges, and justify why a multi-domain approach is superior to focusing on a single barrier type.

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A multi-component transitions-of-care program should incorporate interventions across all five barrier domains. Patient-related: Implement bedside discharge counseling using teach-back for all patients with ≥ 5 medications, with materials available in the top five languages spoken in the community. Therapy-related: Mandate pharmacist-led medication reconciliation at admission, transfer, and discharge (with documented resolution of all discrepancies). Socioeconomic: Screen all patients using PRAPARE before discharge and connect those with identified SDOH barriers to financial counseling, PAPs, and community resources. Offer bedside medication delivery or meds-to-beds programs. Health-system: Establish post-discharge pharmacist follow-up calls at 48–72 hours, with warm handoffs to community pharmacists for ongoing MTM. Create a shared electronic platform for hospital-to-community communication. Condition-related: Stratify patients by readmission risk using validated tools (e.g., LACE index) and allocate more intensive follow-up to high-risk patients. Measurement: Track 30-day readmission rates, PDC for key medications, patient satisfaction scores, and number of drug-related problems resolved. A multi-domain approach is superior because barriers rarely occur in isolation—a patient may understand their medications perfectly but still be readmitted due to cost-related non-adherence or lack of follow-up. Addressing only one domain leaves other barriers active, limiting the overall effectiveness of the program. Anticipated challenges include pharmacy staffing for post-discharge calls, EHR interoperability between hospital and community pharmacy, and ensuring consistent screening compliance.

SUMMARY

Barriers and Interventions — Key Concepts Review

Summary

Pharmacists play a central role in identifying and resolving barriers to optimal pharmacotherapy. The five-domain model classifies barriers as patient-related (literacy, cognition, motivation, beliefs), therapy-related (complexity, ADRs, polypharmacy), socioeconomic (cost, insurance, transportation), health-system (formulary, care coordination, access), and condition-related (asymptomatic disease, comorbidities). Adherence can be quantified using MPR and PDC, with ≥ 80% serving as the standard threshold. Assessment tools include the MMAS-8, teach-back method, PRAPARE screening, and motivational interviewing.

Interventions are organized into four tiers: patient-level (education, MI, adherence aids, cultural competence), therapy-level (regimen simplification, ADR management, deprescribing, formulation changes), socioeconomic (generic substitution, PAPs, 90-day supplies, community referrals), and health-system (MTM/CMR, prior authorization support, transitions of care, collaborative practice agreements). The pharmacist must accurately diagnose the barrier before selecting the intervention, follow the Assess–Identify–Intervene–Monitor cycle, and address barriers across multiple domains simultaneously to achieve person-centered therapeutic outcomes.