B Pharmacy Sem 7: Pharmacy Practice

Explore community & hospital pharmacy operations, inventory control, drug info services, patient counseling, health screenings & TDM to optimize medication use.

Subject 3 . Pharmacy Practice

1. Community Pharmacy Organization & Management
2. Hospital Pharmacy Organization & Drug Distribution
3. Drug Store Management & Inventory Control
4. Drug Information Services & Sources
5. Patient Medication History Interview & Counseling
6. Health Screening Services
7. Clinical Pharmacy & Therapeutic Drug Monitoring Basics

Unit 1: Community Pharmacy Organization & Management

Community pharmacies are the frontline of healthcare, providing medication dispensing, patient counseling, and over‑the‑counter (OTC) services. This unit covers the structure, workflow, key responsibilities, and common challenges in managing a community pharmacy.

1. Definition & Role

• Definition:
  A community pharmacy is a retail facility where licensed pharmacists dispense prescription medications, recommend OTC products, and offer health‑related services to the public.

• Core Roles:

  1. Dispensing & Verification: Fill prescriptions accurately and verify appropriateness (dose, interactions).

  2. Patient Counseling: Educate patients on proper use, side‑effects, and adherence strategies.

  3. OTC Recommendations: Guide self‑care for minor ailments (pain, cough, allergies).

  4. Health Promotion: Offer screenings (blood pressure, glucose), immunizations, and wellness advice.

2. Physical Layout & Infrastructure

1. Dispensing Area

   • Secure prescription drop‑off/pick‑up counter with computer terminal and lockable storage for controlled drugs.

2. Counseling Space

   • Private or semi‑private area with seating and informational materials.

3. OTC/Product Display

   • Shelving organized by therapeutic category; clear signage for quick reference.

4. Inventory Storage

   • Ambient, refrigerated, and controlled‑substance cabinets; FIFO (First In, First Out) rotation.

5. Technology Systems

   • Pharmacy management software for prescription processing, drug‑interaction checking, and record‑keeping.

3. Staffing & Responsibilities

4. Workflow & Process Controls

1. Prescription Receipt

   • Verify patient identity, authenticate prescription, and check for completeness.

2. Data Entry & Clinical Screening

   • Enter prescription into system; screen for allergies, interactions, dosage errors.

3. Medication Preparation

   • Accurately count/measure, label bottles, affix auxiliary labels (e.g., “Take with food”).

4. Pharmacist Verification

   • Final check of drug, strength, patient instructions; document approval.

5. Patient Counseling & Handoff

   • Explain regimen, answer questions, provide printed information leaflets.

6. Documentation & Record‑Keeping

   • Maintain records of controlled substances, immunizations, clinical interventions.

5. Regulatory & Quality Considerations

• Licensing & Accreditation:

  • Registration with state or national pharmacy councils; periodic renewals and inspections.

• Controlled Substances Management:

  • Strict record‑keeping (e.g., Narcotic Registers), secure storage, regular audits.

• GMP in Retail:

  • Maintain temperature‑ and humidity‑controlled storage; adhere to manufacturer’s handling instructions.

• Patient Privacy:

  • Comply with data‑protection regulations; secure digital records and confidential counseling.

6. Common Challenges & Best Practices

7. Key Exam Tips

• Outline the 6‑step prescription workflow clearly.

• Differentiate roles of pharmacists vs. technicians in community practice.

• List at least three quality safeguards (e.g., barcode checks, temperature logs).

• Discuss one patient‑care service (e.g., immunization) and its regulatory requirements.

Unit 2: Hospital Pharmacy Organization & Drug Distribution

Hospital pharmacies support inpatient and outpatient care by managing formulary selection, sterile and non‑sterile compounding, and efficient drug distribution systems. This unit examines the structure, services, workflow, and quality controls unique to the hospital setting.

1. Definition & Role

• Definition:
  A hospital pharmacy is an integrated clinical service within a healthcare institution, responsible for preparing, dispensing, and monitoring medications for hospitalized patients and outpatient clinics.

• Core Functions:

  1. Formulary Management: Select and maintain a list of approved medications based on efficacy, safety, and cost.

  2. Sterile Compounding: Aseptic preparation of IV admixtures, chemotherapy, and parenteral nutrition under sterile conditions.

  3. Automated Dispensing: Use of ADCs (Automated Dispensing Cabinets) or unit‑dose systems to streamline medication access.

  4. Clinical Support: Pharmacist participation in rounds, therapeutic drug monitoring, and ADR reporting.

2. Organizational Structure

3. Drug Distribution Systems

1. Floor‑Stock System

   • Bulk supplies of common medications stored on nursing units; requires periodic restocking and monitoring.

2. Unit‑Dose System

   • Individually packaged doses labeled for specific patients; minimizes errors and waste.

3. Automated Dispensing Cabinets (ADCs)

   • Computer‑controlled cabinets located on wards; track drug removal via user authentication and dosage logs.

4. Pharmacy‑to‑Ward Pneumatic Tubes

   • Rapid transport of small medication orders or compounding requests between pharmacy and nursing stations.

5. Closed‑Loop Medication Management

   • Integration of electronic prescribing (CPOE), barcode medication administration (BCMA), and ADCs to ensure “five rights.”

4. Workflow & Key Processes

1. Order Receipt & Verification

   • Electronic or handwritten orders received; pharmacist verifies appropriateness, dose, and potential interactions.

2. Dispensing & Compounding

   • Non‑sterile items picked or packaged; sterile admixtures prepared in laminar‑flow hoods following aseptic technique.

3. Distribution & Documentation

   • Medications delivered to wards via ADC restocking or unit‑dose carts; records updated in pharmacy information system.

4. Clinical Review & Monitoring

   • Pharmacokinetic dosing (e.g., aminoglycosides, vancomycin), renal dosing adjustments, and therapeutic drug monitoring.

5. Return & Waste Management

   • Expired or unused medications returned to pharmacy; controlled substances handled per regulatory guidelines.

5. Quality Assurance & Safety

• Cleanroom Validation:

  • Routine environmental monitoring (microbial and particulate), certification of ISO Class levels, and HEPA filter integrity checks.

• Sterility Assurance:

  • Media fill tests (simulated aseptic runs), surface sampling, and personnel competency evaluations.

• Barcoding & Electronic Systems:

  • BCMA and barcode scanning of patient ID and drug package to prevent administration errors.

• Medication Error Reporting:

  • Non‑punitive incident reporting system; root-cause analyses and corrective‑preventive actions (CAPA).

6. Common Challenges & Mitigation

7. Key Exam Tips

• Differentiate floor‑stock, unit‑dose, and ADC systems, citing pros and cons.

• Sketch a cleanroom layout, labeling ISO classifications for buffer and ante‑areas.

• Outline the “closed‑loop” medication management cycle and its safety checks.

• Describe one QA test (e.g., media fill) and its acceptance criteria for sterile compounding.

Unit 3: Drug Store Management & Inventory Control

Efficient drug store management ensures continuous supply, cost control, and compliance with regulatory standards. This unit details the principles, analytical methods, and workflow for inventory optimization in community and hospital pharmacy settings.

1. Definition & Objectives

• Definition:
  Systematic planning, acquisition, storage, and distribution of pharmaceutical stock to meet patient needs while minimizing waste and cost.

• Objectives:

  1. Maintain optimal stock levels to prevent shortages and overstocking.

  2. Ensure product integrity through proper storage conditions and stock rotation.

  3. Control inventory costs via data‑driven ordering and supplier management.

  4. Support regulatory compliance with accurate records and audit readiness.

2. Inventory Classification Techniques

1. ABC Analysis

   • Purpose: Categorize items by annual consumption value.

   • Classes:

     • A-items (≈70–80% value, 10–20% of items): Tight control, frequent review.

     • B-items (≈15–25% value, 20–30% of items): Moderate control.

     • C-items (≈5–10% value, 50–70% of items): Simplified control, bulk ordering.

2. VED Analysis

   • Purpose: Prioritize items by criticality to operations.

   • Categories:

     • V (Vital): Life‑saving drugs—never allow stock‑outs.

     • E (Essential): Important for therapy but short‑term stock‑outs manageable.

     • D (Desirable): Lower priority; longer stock‑outs acceptable.

3. FSN Analysis

   • Purpose: Classify based on movement speed over time.

   • Groups:

     • F (Fast‑moving): High turnover—monitor closely.

     • S (Slow‑moving): Occasional use—limit order quantity.

     • N (Non‑moving): No issue in defined period—consider delisting.

4. XYZ Analysis

   • Purpose: Assess value variability in consumption.

   • Classes:

     • X (Constant consumption): Predictable demand.

     • Y (Moderate variability): Seasonal or trend‑based demand.

     • Z (Highly variable): Irregular demand—order on need basis.

3. Reorder Strategies & Economic Order Quantity (EOQ)

• Reorder Point (ROP):

  $$\text{ROP} = \text{Lead Time Demand} + \text{Safety Stock}$$

  Ensures new orders arrive before stock depletion.

• Safety Stock:
  Buffer stock to cover demand variability and supply delays.

• Economic Order Quantity (EOQ):

  $$EOQ = \sqrt{\frac{2DS}{H}}$$

  where

  • $D$ = annual demand

  • $S$ = ordering cost per order

  • $H$ = holding cost per unit per year

• Just‑in‑Time (JIT):
  Minimize on‑hand inventory by aligning orders closely with actual demand.

4. Storage & Stock Rotation

• Storage Conditions:

  • Ambient: 20–25 °C, 40–60% RH for most solid and liquid dosage forms.

  • Refrigerated: 2–8 °C for temperature‑sensitive injectables and vaccines.

  • Controlled Substances: Secure, lockable cabinets with restricted access.

• Stock Rotation:

  • FEFO (First‑Expired, First‑Out): Prioritize dispensing of soon‑to‑expire items.

  • FIFO (First‑In, First‑Out): For items without strict expiry concerns.

• Environmental Monitoring:

  • Periodic temperature and humidity logs.

  • Alarm systems for excursions beyond limits.

5. Record‑Keeping & Audit Trails

• Inventory Ledger:

  • Maintain perpetual records of receipts, issues, and balances.

  • Include batch numbers and expiry dates for traceability.

• Cycle Counting:

  • Regular partial counts to verify record accuracy without full shutdown.

• Audit Preparation:

  • Organized storage of invoices, order records, and stock‑taking reports.

  • Documentation of corrective actions for discrepancies.

6. Technology & Automation

• Inventory Management Software:

  • Real‑time tracking, automated reorder alerts, and reporting dashboards.

• Barcode & RFID Systems:

  • Expedite receiving, picking, and dispensing; reduce manual errors.

• Automated Storage & Retrieval Systems (ASRS):

  • High‑density shelving with robotic access, ideal for high‑volume hospitals.

7. Common Challenges & Solutions

8. Key Exam Tips

• Explain ABC and VED analyses with clear examples.

• Derive and interpret the EOQ formula and its components.

• Distinguish FEFO vs. FIFO and state when each is applied.

• Describe cycle counting and its importance for audit readiness.

Unit 4: Drug Information Services & Sources

Pharmacists serve as the primary drug information resource for healthcare professionals and patients. This unit covers the definition, types of information resources, workflow for responding to queries, and best practices to ensure accurate, evidence‑based responses.

1. Definition & Role

• Definition:
  Drug Information Services (DIS) systematically collect, evaluate, and disseminate unbiased, current information about drugs, including dosing, interactions, adverse effects, and therapeutic use.

• Core Roles:

  1. Answer clinical queries from physicians, nurses, and patients.

  2. Support formulary decisions by reviewing evidence on efficacy, safety, and cost.

  3. Educate healthcare staff through in‑service training, newsletters, or bulletins.

  4. Monitor new literature for safety alerts, label changes, and emerging therapies.

2. Types of Information Resources

3. Query Handling Workflow

1. Receipt & Clarification

   • Record requestor details, clinical context, and specific question.

   • Clarify any ambiguities (e.g., patient age, comorbidities, concomitant drugs).

2. Literature Search

   • Begin with tertiary for quick facts; proceed to secondary to identify primary studies.

   • Use Boolean operators and filters (publication date, study design) for efficiency.

3. Critical Appraisal

   • Evaluate study quality: randomized vs. observational, sample size, bias risk.

   • Synthesize findings, noting limitations and relevance to the query.

4. Formulate Response

   • Provide concise, evidence‑based answer with references.

   • Include dosing recommendations, monitoring parameters, and alternative options if applicable.

5. Documentation & Follow‑Up

   • Log query and response in DIS database for future reference and quality metrics.

   • Follow up on any further questions or clarify implementation issues.

4. Quality Assurance in DIS

• Standard Operating Procedures (SOPs):
  Define roles, documentation standards, and turnaround times (e.g., urgent vs. non‑urgent).

• Peer Review:
  Critical responses vetted by a second pharmacist or clinical expert.

• Performance Metrics:
  Track number of queries, response times, user satisfaction, and outcome measures (e.g., prevented medication errors).

• Continuous Education:
  Regular training on new resources, literature‑search techniques, and critical appraisal skills.

5. Common Query Types & Strategies

6. Advantages & Limitations

• Advantages:

  • Centralizes expert knowledge, reducing variability in information.

  • Improves patient safety and therapeutic outcomes through evidence‑based guidance.

  • Supports interdisciplinary collaboration and formulary management.

• Limitations:

  • Information overload—requires skill to rapidly identify relevant data.

  • Potential for outdated resources—necessitates continuous updating.

  • Time constraints in urgent clinical settings may limit depth of review.

7. Key Exam Tips

• Outline the 5‑step query workflow clearly.

• Differentiate primary, secondary, and tertiary sources with examples.

• Describe one quality‑assurance measure (e.g., peer review) and its importance.

• Practice formulating a sample response to a dosing query in renal impairment, including references.

Unit 5: Patient Medication History Interview & Counseling

This unit equips you with the skills to gather accurate medication histories and provide effective patient counseling, both of which are critical for optimizing therapy, improving adherence, and preventing medication‑related problems.

1. Definitions & Objectives

• Medication History Interview:
  A structured conversation to collect complete and accurate information on all medications a patient is taking, including prescription drugs, OTC products, herbal supplements, and vaccines.

• Patient Counseling:
  The process of educating patients about their medications—indication, dosage, administration, side effects, and storage—with the goal of ensuring safe and effective use.

Objectives:

1. Identify potential drug‑related problems (interactions, duplications, contraindications).

2. Assess patient’s understanding and adherence to prescribed therapy.

3. Provide clear, personalized instructions to enhance adherence and minimize adverse effects.

4. Document findings and interventions to support continuity of care.

2. Components of Medication History

1. Prescription Medications

   • Drug name, strength, dosage form, route, frequency, duration, prescriber.

2. Over‑the‑Counter (OTC) Products

   • Analgesics, antacids, cough/cold remedies; note brand and active ingredients.

3. Herbal & Dietary Supplements

   • Botanicals, vitamins, minerals—potential for significant herb–drug interactions.

4. Allergies & Adverse Reactions

   • Type of reaction (rash, anaphylaxis); date and severity.

5. Adherence Assessment

   • Missed doses, reasons for non‑adherence (cost, side effects, regimen complexity).

6. Medical History & Comorbidities

   • Conditions that influence pharmacotherapy (renal/hepatic impairment, pregnancy).

3. Interview Process & Techniques

1. Preparation

   • Review available medical records and previous medication lists.

   • Ensure privacy and minimal distractions.

2. Open‑Ended Questions

   • “Can you tell me all the medicines you take, including vitamins or herbal products?”

3. Use “Brown Bag” Review

   • Ask patients to bring all medication containers for visual verification of products and expiry dates.

4. Clarification & Verification

   • Confirm drug names (generic vs. brand), dosing schedules, and administration techniques (e.g., inhaler use).

5. Active Listening & Empathy

   • Reflect back (“So you take your blood pressure pill every morning before breakfast, correct?”).

   • Acknowledge concerns (“I understand the side effects worry you; let’s talk about ways to manage them.”).

6. Documentation

   • Record information in standardized forms or electronic records, noting date and interviewer’s name.

4. Patient Counseling Components

1. Introduction & Purpose

   • Explain your role and the goal of the session (“I’d like to talk about your new medication so you’re comfortable taking it.”).

2. INDICATION & EXPECTED BENEFITS

   • Describe why the drug is prescribed and how it will help.

3. DOSING & ADMINISTRATION

   • Specify dose, timing, with/without food, technique (e.g., how to use an inhaler or apply a cream).

4. DURATION & FOLLOW‑UP

   • Clarify how long to take the medicine and when to return for check‑up or lab tests.

5. SIDE EFFECTS & MANAGEMENT

   • Common and serious adverse effects; what to do if they occur and when to seek medical attention.

6. INTERACTIONS & PRECAUTIONS

   • Potential food–drug, drug–drug, and OTC interactions; storage conditions.

7. ADHERENCE STRATEGIES

   • Pill organizers, reminder apps, linking doses to daily routines.

8. QUESTIONS & TEACH‑BACK

   • Invite questions and use teach‑back (“Can you show me how you’ll use this inhaler?”) to confirm understanding.

5. Common Pitfalls & Solutions

6. Applications & Outcomes

• Medication Reconciliation: Identifying discrepancies between what patients actually take and prescriber orders, reducing errors at transitions of care.

• Chronic Disease Management: Educating patients with diabetes, hypertension, or asthma improves adherence and clinical outcomes.

• Polypharmacy Reviews: Older adults on multiple medications benefit from comprehensive counseling to minimize adverse drug events.

7. Key Exam Tips

• Outline the 8 counseling components clearly, emphasizing teach‑back.

• Describe “brown bag” review and its role in accurate history taking.

• Give examples of two high‑risk situations (e.g., warfarin management) and counseling strategies.

• Practice phrasing open‑ended vs. closed‑ended questions in medication interviews.

Unit 6: Health Screening Services

Health screening in pharmacy practice encompasses a range of point‑of‑care tests and assessments designed to detect risk factors or early signs of disease, enabling timely referrals and interventions.

1. Definition & Objectives

• Definition:
  Pharmacy‑based health screening involves non‑invasive or minimally invasive tests and measurements conducted by pharmacists to evaluate patient health status and identify potential issues.

• Objectives:

  1. Early Detection: Identify asymptomatic conditions (e.g., hypertension, hyperlipidemia, diabetes).

  2. Risk Stratification: Assess patient risk for cardiovascular, metabolic, or other chronic diseases.

  3. Patient Education: Provide immediate lifestyle and medication counseling based on results.

  4. Referral & Follow‑Up: Guide patients to physicians or specialists when needed.

2. Common Screening Services

3. Workflow & Best Practices

1. Patient Preparation

   • Explain procedure and obtain consent.

   • Ensure appropriate fasting (if required) and rest period before measurements.

2. Equipment Calibration & Maintenance

   • Regular calibration of BP cuffs, glucose meters, and lipid analyzers per manufacturer guidelines.

   • Document calibration dates and maintenance logs.

3. Standardized Measurement Techniques

   • Blood Pressure: Patient seated, arm at heart level; multiple readings ≥1 minute apart.

   • Glucose & Lipids: Follow manufacturer’s protocol for strips/reagents; quality‑control checks with known standards.

   • Anthropometrics: Consistent landmarks for tape placement; remove bulky clothing.

4. Result Interpretation & Counseling

   • Compare readings to established guidelines (e.g., JNC 8 for BP, ADA for glucose).

   • Provide immediate lifestyle advice (diet, exercise) and discuss medication adjustments with prescriber if indicated.

5. Documentation & Referral

   • Record results in patient’s record with date/time, equipment ID, and operator initials.

   • Develop referral protocols for values outside target ranges (e.g., ≥140/90 mm Hg, fasting glucose ≥126 mg/dL).

4. Quality Assurance & Safety

• Training & Competency:

  • Staff certification on measurement techniques and device operation.

• Infection Control:

  • Use of single‑use lancets, proper glove use, and disposal of sharps in approved containers.

• Data Privacy:

  • Secure storage of patient data in compliance with local regulations.

• Equipment QC:

  • Routine performance checks (e.g., control solutions for glucose meters).

5. Applications & Impact

• Chronic Disease Prevention: Early identification leads to timely interventions, reducing long‑term complications.

• Pharmacy–Physician Collaboration: Strengthens interprofessional relationships through shared patient care responsibilities.

• Public Health Role: Community access points for screenings increase reach, especially in underserved areas.

6. Common Challenges & Solutions

7. Key Exam Tips

• List at least four common screening tests and their thresholds (e.g., BP ≥140/90 mm Hg).

• Describe the correct procedure for blood pressure measurement.

• Explain infection‑control measures for point‑of‑care testing.

• Outline referral criteria and documentation requirements for abnormal results.

Unit 7: Clinical Pharmacy & Therapeutic Drug Monitoring (TDM) Basics

Clinical pharmacy integrates pharmacists into the patient‑care team to optimize drug therapy, while Therapeutic Drug Monitoring (TDM) uses drug concentration measurements to ensure efficacy and safety. This unit covers both concepts’ definitions, principles, workflow, and key considerations.

1. Definitions & Objectives

• Clinical Pharmacy:
  A patient‑focused practice in which pharmacists collaborate with physicians and other healthcare professionals to design, implement, and monitor medication regimens, aiming to improve therapeutic outcomes.

• Therapeutic Drug Monitoring (TDM):
  The measurement and interpretation of drug concentrations in biological fluids—most commonly plasma—used to individualize dosing and maintain drug levels within a defined therapeutic window.

Objectives:

1. Maximize efficacy by achieving target drug concentrations.

2. Minimize toxicity by avoiding supratherapeutic levels.

3. Account for patient‑specific factors (age, organ function, drug interactions).

4. Provide dose recommendations based on pharmacokinetic principles.

2. Principles of TDM

1. Pharmacokinetic Sampling:

   • Trough level: Collected immediately before the next dose; reflects minimum concentration (C_min).

   • Peak level: Collected at the time of expected maximum concentration (C_max), often 1–2 hours post-dose for many drugs.

2. Therapeutic Window:

   • Range between the minimum effective concentration (MEC) and the minimum toxic concentration (MTC); dosing aims to keep plasma levels within this window.

3. Analytical Methods:

   • HPLC or immunoassays for quantitation of drug in plasma/serum.

   • Turnaround time must be rapid enough to inform timely dose adjustments.

4. Pharmacokinetic Parameters:

   • Clearance (Cl): Volume of plasma cleared of drug per unit time.

   • Volume of distribution (Vd): Apparent volume in which drug is distributed.

   • Half‑life (t½): Time required for plasma concentration to decrease by 50%.

   Relationships:

   $$\text{Dose rate} = Cl \times C_{\text{ss}} \quad\text{and}\quad t_{1/2} = \frac{0.693 \times V_d}{Cl}$$

3. Clinical Pharmacy Workflow

1. Medication Order Review:

   • Evaluate appropriateness of drug choice, dose, route, and duration.

   • Screen for interactions, allergies, and organ function considerations.

2. Initiation of TDM:

   • Identify drugs requiring monitoring (e.g., aminoglycosides, vancomycin, digoxin, lithium, phenytoin).

   • Determine sampling schedule (peak/trough) based on drug’s PK profile.

3. Sample Collection & Analysis:

   • Ensure correct timing relative to dosing.

   • Send samples to lab with clear labeling of time and dose history.

4. Interpretation of Results:

   • Compare measured concentrations to therapeutic range.

   • Consider factors affecting levels: compliance, interactions, disease states.

5. Dose Adjustment Recommendations:

   • Use pharmacokinetic equations to calculate new dose or dosing interval.

   • Document rationale and communicate with prescriber.

6. Follow‑Up Monitoring:

   • Schedule repeat levels after dose change or clinical events (e.g., renal impairment).

   • Record outcomes and any adverse effects.

4. Key Considerations & Challenges

5. Applications of TDM

• Aminoglycosides (Gentamicin, Amikacin):

  • Narrow therapeutic index; nephrotoxicity and ototoxicity risks necessitate peak/trough monitoring.

• Vancomycin:

  • Monitor trough levels to prevent nephrotoxicity and ensure efficacy against resistant organisms.

• Antiepileptics (Phenytoin, Carbamazepine):

  • Non‑linear kinetics (phenytoin) require careful interpretation and dose adjustments.

• Cardiac Glycosides (Digoxin):

  • Low therapeutic window; levels influenced by renal function and drug interactions.

• Mood Stabilizers (Lithium):

  • Regular monitoring essential due to narrow range and renal elimination.

6. Advantages & Limitations

• Advantages:

  • Tailors therapy to individual patient needs.

  • Reduces incidence of adverse drug reactions.

  • Supports evidence‑based dosing adjustments.

• Limitations:

  • Requires laboratory infrastructure and trained personnel.

  • Turnaround time may delay dosing decisions.

  • PK variability and assay limitations can complicate interpretation.

7. Key Exam Tips

• List drugs commonly monitored with TDM and rationale.

• Describe sampling schedules for peak and trough levels.

• Write the basic PK equations for dose adjustment (e.g., new dose = desired concentration × Vd).

• Discuss clinical factors** (renal function, drug interactions) that necessitate TDM.

• Illustrate a sample dose‑adjustment calculation based on measured level and clearance.