L3 - Role of Pharmacists in Clinical Decision Making – Comprehensive Study Notes

Learning Objectives

• Understand the pharmacist’s evolving scope in clinical decision-making (CDM)
• Explain pharmacist-led services (BPMH, med reconciliation, reviews, TDM, MI, vaccinations, community prescribing)
• Describe collaborative care models (PPMC, GP-pharmacist)
• Recognise digital resources & CDSS that underpin safe, evidence-based practice

Core Responsibilities of a Modern Pharmacist

• Medication-therapy expert beyond supply/dispensing
– Patient-centred counselling, education, adherence monitoring
– Evidence sourcing & drug-information provision
• Prescribing support
– Identify/resolve medication-related problems (MRPs)
– Clinical assessment of doses, DDIs, renal/hepatic adjustment – always collaborative with prescribers
• Medication-safety advocate
– Verify prescription legality/accuracy, educate on proper use, monitor for ADRs, report errors
• Expanded scope (last decade)
– Medication reviews (MedsCheck/HMR)
– Chronic-disease programs, vaccinations, prescribing of select medicines

Patient-Centred CDM Framework

1. Collect ➔ comprehensive history, labs, social factors

2. Assess ➔ analyse data, consult references, identify problems

3. Plan ➔ formulate evidence-based recommendations

4. Implement ➔ communicate & enact therapy plan

5. Follow-up/Monitor ➔ evaluate outcomes & modify if required

Clinical Services by Setting

1. Hospital-Based Services

Best Possible Medication History (BPMH)

• Structured, comprehensive list taken on admission – foundation of all downstream CDM
• Goals
– Support accurate prescribing
– Detect/resolve information discrepancies → minimise harm & avoidable readmission
• Sequential steps

1. Review existing records (e.g., My Health Record)

2. Introduce self & purpose to patient/carer

3. Allergy/ADR screen first

4. Core medication information (see detailed list below)

5. Use checklist to assure completeness

6. Assess adherence/understanding

7. Triangulate with ≥2 secondary sources (community pharmacy, GP, nursing charts, recent discharge summaries, SafeScript for S8/S4D)

8. Document & share (becomes legal record)
   • Detailed info to obtain (ask for each category)
   – Prescription meds
   – OTC/non-prescription
   – Complementary & herbal
   – Short-term/PRN
   – Infrequently used (e.g., yearly ext{denosumab} inj.)
   – Topical, inhaled, eye/ear, patches
   – Devices/supplies (insulins, pumps)
   – Social/recreational drugs, alcohol, nicotine, cannabis
   – For each item record: name, strength, dose, frequency, route, day-of-week for cyclic therapy, indication, start date/duration, recent changes & reasons, monitoring parameters (e.g., last INR / target INR 2.0–3.0 for warfarin)

Admission & Discharge Medication Reconciliation

• Compare in-hospital orders with home regimen
• Detect omissions, duplications, dosing errors, DDIs
• Perform at BOTH transitions (entry & exit) because therapy may change during stay
• Process: obtain BPMH ⟶ verify ⟶ resolve discrepancies ⟶ document & maintain current list

Medication Review (In-patient)

• Conducted weekly for long-stay patients
• Incorporates new labs/clinical status
• Systematic approach
– Collect (history, med list, labs)
– Assess (indication, effectiveness, safety, adherence)
– Identify MRPs (duplication, under/over-dosing, interactions)
– Develop recommendations & communicate to prescriber
– Document & follow-up

Therapeutic Drug Monitoring (TDM)

• Measure serum concentrations at scheduled times to keep drug in therapeutic window, prevent toxicity
• Common drugs & rationale
– Vancomycin (narrow window, nephrotoxicity)
– Gentamicin (ototoxic/nephrotoxic)
– Phenytoin (non-linear kinetics)
– Lithium (neuro-/nephrotoxicity)
– Tacrolimus (transplant rejection vs. toxicity)
– Theophylline (arrhythmias/seizures)
• Pharmacist roles
– Interpret levels vs. dose timing, renal/hepatic fx, DDIs
– Recommend dose/interval changes using PK principles
– Educate clinicians/patients on sampling, adherence

Medicines Information (MI) Service

• Centralised expert advice point (phone/email/fax)
• Handles clinical, legal & PBS queries
• Duties
– Evaluate complex questions (DDIs, pregnancy, paediatrics, geriatrics, renal/liver dosing)
– Consult national formularies & databases, synthesise evidence
– Support access/navigation of PBS authorities
– Maintain documentation for medico-legal audit

2. Community Pharmacy Services

Vaccination Workflow

1. Assess eligibility & screen contraindications

2. Select vaccine & schedule

3. Obtain informed consent, provide education (benefits, AEFIs)

4. Administer, monitor 15 min for anaphylaxis

5. Document in AIR, provide record card, arrange follow-up

Pharmacist Prescribing Services (state/territory dependent)

a) Uncomplicated UTI Service

• Non-pregnant females 18–65 years with classic symptoms
• Steps: symptom assessment, rule-out red flags (fever, flank pain, pregnancy, recurrent UTI, immunosuppression) ⟶ supply oral antibiotic per protocol ⟶ counsel ⟶ safety-net referral if red flags

b) Minor Skin Conditions

• Only four authorised conditions: eczema/dermatitis, shingles (herpes zoster), impetigo, mild plaque psoriasis
• Gather history, severity grading, exclude red flags (systemic Sx, immunocompromise)
• Supply protocol meds (topical corticosteroids, antivirals, antibiotics, coal tar, etc.)
• Provide written care plan; refer when out of scope

c) Oral Contraceptive Pill (OCP) Supply

• Continuation or initial supply depending on jurisdiction
• Screen BP, VTE risk, migraine w/ aura, smoking ≥35 yrs, meds affecting efficacy
• Counsel on adherence, missed-pill steps, side-effects, STIs; arrange follow-up or alternative contraception referral if contraindicated

MedsCheck vs. Home Medication Review (HMR)

• MedsCheck
– Conducted in-pharmacy; pharmacist-initiated; no GP referral
– Focus on high-risk or polypharmacy pts; brief consultation
– Document internally; optional GP notification; no formal follow-up
• HMR
– Conducted in patient’s home; requires valid GP referral (MBS item)
– Targets complex cases (post-discharge, frail elderly)
– Comprehensive review & written report to GP; structured GP-led follow-up

3. Collaborative Models

Partnered Pharmacist Medication Charting (PPMC)

• Credentialed pharmacist & doctor jointly discuss BPMH & therapy plan
• Pharmacist documents chart; doctor co-signs → authorises nursing administration
• Reduces errors because full BPMH precedes any charting (contrast to conventional model where brief history by MO precedes pharmacist reconciliation)
• Demonstrated Australian success in error reduction & timely therapy

GP-Pharmacist Integration

• Pharmacist embedded in primary-care clinic; employed by practice or PHN
• Non-dispensing, focus on medication optimisation for chronic / complex pts
• Workflow
– Receive GP referral or trigger via EMR flags
– Conduct review, educate patient, develop plan
– Record notes in shared EMR, discuss directly with GP & nurses

Resources for Evidence-Based Decisions (AU-centric)

• AMH – Australian Medicines Handbook (adult dosing, ADRs, practice notes)
• TG: Therapeutic Guidelines (disease-specific algorithms)
• Don’t Rush to Crush (oral formulation modification)
• AIDH – Australian Injectable Drugs Handbook (IV compatibilities)
• APF – Aust. Pharmaceutical Formulary (compounding & professional practice)
• eviQ – oncology protocols, dose calculators
• ESTABLISHED Drug Interactions (micromedex/stockley)

Digital Tools & Clinical Decision Support Systems (CDSS)

• GuildCare / MedAdvisor – service management (MedsCheck, DAA), adherence alerts
• SafeScript – real-time monitoring of S8 & S4D prescriptions, detects doctor-shopping
• eMM (electronic medication management) platforms – in-built alerts for allergies, DDIs, duplicate therapy; auto-stop dates
• DoseMe Rx / InsightRx – Bayesian TDM dosing support (see next section)
• MMR/HMR software – structured templates & evidence links

Bayesian Forecasting for Personalised Dosing

• Inputs: patient demographics, dose history, sampling times, serum concentrations, renal/liver function, pharmacogenomics
• Algorithm combines population PK model with individual data (Bayes theorem) → generates personalised PK/PD profile
• Outputs: predicted C{min}, AUC{24}, recommended dose & interval achieving target exposure within therapeutic window
• Advantages: maximises efficacy & safety, accommodates sparse sampling, ideal for drugs with narrow TI (vancomycin, aminoglycosides, tacrolimus)
• Example equation used under the hood (conceptual):
P(\theta|Y)=\frac{P(Y|\theta)\times P(\theta)}{P(Y)}
where \theta = individual PK parameters, Y = observed concentrations

Additional Equations/Calculations Frequently Applied

• Cockcroft–Gault for CrCl (dosing renal adjust):
\text{CrCl}=\frac{(140-\text{age})\times \text{weight (kg)}}{72\times \text{SCr (mg/dL)}}\times 0.85 (if female)
• INR therapeutic range for typical AF/VT prophylaxis: 2.0–3.0

Ethical, Legal & Practical Considerations

• Obtain informed consent for any service (vaccination, prescribing, review)
• Work within state legislation/scope (e.g., pharmacist prescribing criteria differ by state)
• Documentation is a legal record; omit none, write clearly, time/date/sign
• Maintain patient privacy when accessing secondary sources (MyHR, SafeScript)
• Duty of referral: recognise red flags beyond scope and escalate promptly

Connections to Previous Learning

• Builds on last week’s general CDM lecture (Hannah) ➔ now focused on pharmacist-specific services
• Reinforces foundational principles: patient-centred care, inter-professional collaboration, evidence-based practice

Real-World Impact

• BPMH accuracy directly linked to reduced inpatient harm & readmissions
• Community prescribing services increase access, reduce GP burden, improve public-health vaccination rates
• PPMC & GP-pharmacist models showcase value of pharmacists in multidisciplinary teams, leading to measurable error reduction and optimisation of chronic-disease outcomes

Key Takeaways

• Medication reviews (hospital & community) are pivotal for identifying, resolving, preventing MRPs
• Clear documentation & communication drive safe prescribing & continuity of care
• CDSS and practice guidelines streamline workflow and provide safety nets
• Community clinical services (UTI, skin, OCP, vaccination) exemplify pharmacists’ independent primary-care role
• Collaborative models (PPMC, GP-pharmacist) demonstrate future directions for integrated medicines management in Australia