17.2 Medication Reconciliation & Duplicate Therapy

Medication Reconciliation

Medication reconciliation is the formal process of creating the most accurate possible list of every medicine a patient is taking, comparing that list against each new prescription, and resolving discrepancies. The DHA blueprint expects pharmacists to perform reconciliation at three trigger points: admission, transfer, and discharge.

Building the Best Possible Medication History (BPMH)

The Best Possible Medication History (BPMH) is the foundation of reconciliation. It must be built using at least two sources, because patient self-report alone misses refill gaps, stopped medicines, and forgetfulness. Acceptable source pairs include:

• Patient or caregiver interview plus a community pharmacy refill record
• Patient interview plus a prior hospital discharge summary
• Pharmacy refill record plus the previous primary-care prescription list

The BPMH captures each drug's name, dose, route, frequency, last dose taken, and indication, plus any over-the-counter medicines, herbal products, vitamins, and PRN agents the patient uses. Allergies and prior adverse reactions are recorded at the same time.

Discrepancy Types

Once the BPMH is built, it is compared against the active inpatient or discharge order set. Four discrepancy categories appear repeatedly on the exam:

Every discrepancy must be documented, communicated to the prescriber, and resolved before the medicine is dispensed. Silent correction by the pharmacist is not acceptable — the prescriber must be contacted.

Reconciliation at Each Trigger Point

• Admission: compare home medicines against admission orders; decide continue/hold/stop for each.
• Transfer (e.g. ICU to ward, or service-to-service): reconcile medicines as orders are rewritten; watch for medicines dropped during handover (e.g. VTE prophylaxis, stress ulcer prophylaxis).
• Discharge: reconcile discharge prescriptions against the inpatient record AND the BPMH; ensure the patient leaves with a clear, written list of what to take, what was stopped, and what was changed. Counsel the patient on changes.

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Duplicate Therapy

Duplicate therapy occurs when a patient receives two medicines that are either from the same therapeutic class or contain the same active ingredient under different names. It is one of the most common preventable causes of adverse drug events in both community and inpatient settings.

Same-Class Duplicates

Same-Active-Ingredient Duplicates

These occur when a patient is prescribed a brand and a generic, or two brands, of the same molecule without realising:

• Panadol (paracetamol 500 mg) + Co-codamol (paracetamol + codeine) — cumulative paracetamol hepatotoxicity.
• Brufen (ibuprofen) + Nurofen (ibuprofen) — duplicate NSAID.
• Glucophage (metformin) + a metformin-containing combination (e.g. Janumet) — duplicate metformin, GI and lactic acidosis risk.

Clinical Red Flags the Pharmacist Must Catch

• Serotonin syndrome from two serotonergic agents: triad of clonus, hyperreflexia, agitation ± hyperthermia. Onset is usually within hours of adding the second agent.
• GI bleed from two NSAIDs: melena, haematemesis, drop in haemoglobin.
• Hyperkalaemia from dual RAAS blockade: peaked T waves, cardiac arrhythmia.
• Hepatotoxicity from duplicate paracetamol: rising ALT/AST, jaundice; daily paracetamol intake should stay below 4 g in adults.

The Pharmacist's Workflow for Duplicate Detection

1. Maintain an active problem list and drug list for each patient.
2. On every new prescription, screen by therapeutic class (ATC code level 3–4) and by active ingredient.
3. When a duplicate is identified, contact the prescriber with the specific risk rather than refusing to dispense silently.
4. Document the intervention and outcome.

A common exam stem shows a patient admitted on sertraline who is then started on tramadol for post-operative pain. The correct pharmacist action is to flag the serotonin syndrome risk and recommend a non-serotonergic analgesic (e.g. paracetamol, morphine).

Exam Trap — Hidden Duplicates at Discharge

A frequent DHA trap gives a discharge prescription list that looks clean until you cross-check the BPMH. The patient was admitted on Panadol (paracetamol 500 mg) and is discharged with Co-codamol (paracetamol 500 mg + codeine 30 mg) plus a PRN paracetamol order — three sources of paracetamol, easily exceeding the 4 g/day adult ceiling and risking hepatotoxicity. The pharmacist must total the daily paracetamol load across all products (prescribed, OTC, and combination) before dispensing, and either consolidate the order or counsel the patient to avoid OTC paracetamol. The same trap appears with ibuprofen dispensed as Brufen alongside an OTC Nurofen the patient was already taking.