SAFE AND EFFECTIVE PRESCRIBING - 2 Safe prescribing a case study and Anticoagulation key messages

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SAFE AND EFFECTIVE PRESCRIBING - 2Safe
prescribing a case study andAnticoagulation key
messages

• Dr Ian Coombes,
• Senior Clinical Lecturer University of Queensland
  Schools of Medicine and Pharmacy
• Safe Medication Practice Unit, Queensland Health

The University of Queensland
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Session Objectives (week 2)

• At the end of these tutorials students should
  have
• An increased awareness of common prescribing
  error traps
• Enable students to apply key principles of safe
  prescribing
• Facilitate students writing regular in hospital
  prescription
• Understand key points for safe prescribing of
  anticoagulants

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To recap why interns make mistakes
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How a patient with documented ADR to
cephalosporin received two more dosesFrom
Reasons Swiss Cheese Model
Verbal order by Surgeon for antibiotic in OT
Transcribed by Registrar to medical notes/record
Phone call Nurse to ward call dr (outlier)
Prescribed by Dr (1st term junior)
Severe anaphylaxis, dialysis, steroids,
antihistamines
Prepared by Nurse 1 (busy)
Check Nurse 2 (agency)
Patient (asleep)
Given by RN
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Re-exposure to Cephalosporin

• Patient Factors
• Sedated, post op
• Task Factors
• Writing a prescription some one else ordered
• Practitioner Factors
• Hungry, tired, late, inexperienced, ill-informed
• Team Factors
• What team? Outlied patient, ward call doctor
• Workplace Factors
• Medicine charts ADRs/Allergies on front of
  chart order on inside
• Organisation Factors
• Did not invest in safety systems or training for
  safe prescribing

• Patient Factors
• ADR/ alert bracelets
• Task Factors
• Reduce delegation of tasks
• Practitioner Factors
• Drs hours training support
• Team Factors
• Safe prescribing lead by consultants
• Workplace Factors
• Medicine charts ADR on chart where prescribing
  administration
• Organisation Factors
• Acknowledge and Invested in safety system
  change education

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• So What is a Prescribing?

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The Prescribing process
Mainly Snr doctors
Patient
Mainly Jnr Doctors And or nursing staff
Coombes I, PhD
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Key stage of prescribing for junior doctors is

• COMMUNICATING information about
• drug
• form
• route
• dose
• frequency
• administration time/s
• administration of IV meds
• duration of therapy
• in a CLEAR, UNDERSTANDABLE form to
• other doctors
• nurses
• pharmacy staff

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Case Study Mr AD

• 68 y.o. 60 kg ? presents to ED
• PC SOB pyrexial and sputum
• HoPC 2/52 increased, cough, sputum, fever 7 days
  of amoxycillin from local (private Dr) no
  response
• Exam BP 110/70 HR 90 RR 19, bi-basal chest
  crackles
• Creatinine, urea other E, LFTs Normal
• PMH RA (10 yrs) HT (20 yrs),
• Dx URTI
• Social Hx lives alone
• ADR Erythromycin severe Hives, rash 2005

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• Your Registrar asks you to write up Mr ADs drug
  chart
• (DOB 01/4/40 UR155566 date today ward
  medical)
• Captopril oral 25mg BD
• Diltiazem SR oral 240mg mane
• Methotrexate oral 10 mg weekly on Sunday morning
• Co-amoxiclav oral1 TDS
• Clarithromycin oral 500mg BD

• 68 y.o. 60 kg ? presents to ED
• PC SOB pyrexial and sputum
• HoPC 2/52 increased, cough, sputum, fever 7 days
  of amoxycillin from local (private Dr) no
  response
• Exam BP 110/70 HR 90 RR 19, bi-basal chest
  crackles
• Creatinine, urea other E, LFTs Normal
• PMH RA (10 yrs) HT (20 yrs),
• Dx URTI
• Social Hx lives alone
• ADR Erythromycin severe Hives, rash 2005

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• Write up the medicines the person should have
• Pass to the Person Next to You

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Is Everything OK?

• Imagine you are a junior nurse at 8 a.m. on
  Friday
• Name - care with sound alikes
• Piroxicam Proscar (trade)
• Drug Form immediate vs sustained release
• e.g. Diltiazem sustained release vs standard
• Combinations Co-amoxiclav contains penicillin
  
• Strengths - if unsure,(1 tablet) make a clinical
  decision
• Route - oral, IV, IM, SC, IT can they take it?
• Dose - multiple/partial tablets decimal points
• e.g. digoxin 62.5 micrograms, 5.0 units insulin
• Frequency - explicit standard terms NB weekly
  medication (cross out unnecessary days)
• Times to be entered by doctor when prescribing?

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ADR Erythromycin Hives

• Marks Patient name 5 marks
• All drug names clear 4 marks
• All routes clear 4 marks
• All doses frequencies 4 marks
• SR form of Diltiazem 4 marks (no SR
  -4!)
• Weekly methotrexate block out 10 marks (Did
  not block out -10 mark
• Did not prescribe Clarithromycin 10 marks,
  (DID prescribe -20 mark

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ADRs

• Class effects (macrolide antibiotics) common
  trap
• BEWARE trade names and combination drugs
• Document all relevant ADR details on chart BEFORE
  prescribing!
• ADR details in medical chart/notes as well
• Ask patient , carer, previous notes
• Check with patient and chart and front of medical
  record file BEFORE prescribing

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Sustained release drugs
What if the patient gets 4 x 60 mg tablets ?
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Hypotensive bradycardic
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Weekly medicines

• Medicines to be taken once a week
• Ie Methotrexate for arthiritis
• Alendronate for osteoporosis
• Significant risk that your order may be
  misinterpreted by nursing staff and patient may
  receive daily pancytopenia

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Ceasing Medications
Physically block further administration
Prevent transcription errors but still legible
for records
Sign and Date, State reason for ceasing
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Reducing the risk of adverse events

• Always
• include a detailed drug history in the
  consultation
• Only
• use drug treatment when there is a clear
  indication
• Stop
• drugs that are no longer necessary
• Check
• dose and response, especially in the young,
  elderly and those with renal, hepatic or cardiac
  disease

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Medication Assessment/ Review

• Does the patient need this drug ?
• Is this drug the most effective and safe ?
• Is this dosage the most effective and safe ?
• If side effects are unavoidable does the patient
  need additional drug therapy for these side
  effects?
• Will drug administration impair safety or
  efficacy ?
• Are there any drug interactions ?
• Will the patient comply with prescribed regimen ?

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Summary

• Accidents happen everywhere
• The best people make mistakes
• Same simple mistake - different consequences
• Everyone is responsible for patient safety
• Writing an order is as important as making the
  decision what to prescribe
• If in doubt check!

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Anticoagulants - Objectives

• Anticoagulation
• Why, where, when and when NOT to!
• Heparins
• Low Molecular Weight Heparin (LMWH)
• Standard Unfractionated Heparin
• Heparinoids (eg danaparoid)
• Warfarin
• Anticoagulation and Surgery
• Reversal

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Anticoagulation The classic balance between
risk and benefit of medication
The margin for error is relatively small
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Past Incidents

• Most frequent cause of preventable drug related
  harm (Quality in Australian Health Care Study)
• Inadequate anticoagulation and emboli
• Warfarin omission on discharge embolic events
• Out-of-hours dosing - bleeds
• Drug interactions resulting in enhanced (eg
  bleeds) or inadequate effects
• LMWH dosing and bleeds

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• Anticoagulation
• Indications?

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Indications for anticoagulation?

• Primary prevention
• Atrial Fibrillation (AF), left ventricular
  dilatation, mural thrombus
• DVT/PE in hospitalised patients (medical and
  surgical)
• Secondary prevention
• Thromboembolic events (DVT, PE)
• Acute coronary syndrome (ACS)
• Peripheral vascular disease (PVD)
• Post CVA AF
• Adjunctive treatment
• Myocardial infarction (MI)

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• Anticoagulation
• Contraindications?

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Contraindications to Anticoagulation?

• Bleeding disorders, including haemophilia
• Uncontrolled active bleeding
• Major trauma or recent surgery
• Thrombocytopenia (including HITTS)
• Cerebral haemorrhage
• Peptic ulcer
• Severe uncontrolled hypertension
• Severe hepatic disease
• Bacterial endocarditis
• heparin/LMWH contraindicated

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Anticoagulation
Prophylaxis Treatment
Initial Mostly fractionated heparin Occasionally unfractionated heparin Mostly fractionated heparin Occasionally unfractionated heparin
Initial Very occasionally warfarin (eg AF)
Subsequent Mostly warfarin Occasionally heparin if warfarin contraindicated (eg pregnancy) Mostly warfarin Occasionally heparin if warfarin contraindicated (eg pregnancy)
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Prophylaxis LMWH

• HIGH RISK
• 40 mg sub-cut 12 hrs pre-op, then once/day for
  7-10 days or until mobilised (NB continue up to
  30/7 for total hip replacement surgery)
• MODERATE RISK
• 20 mg sub-cut 2 hrs pre-op, then once/day for
  7-10 days or until mobilised
• MEDICAL PATIENTS
• 40 mg/day sub-cut for 6-14 days or until
  mobilised
• PROLONGED PROPHYLAXIS (eg hip replacement)
• 40 mg/day sub-cut for up to 30 days
• HAEMODIALYSIS
• 0.5-1 mg/kg (via arterial line) at start of
  session

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Treatment LMWH (enoxaparin)

• ESTABLISHED DVT
• 1 mg/kg BD (inpatients)
• 1.5 mg/kg/day (outpatients)
• High risk patients ? 1 mg/kg BD more beneficial
• Start warfarin on the same day as heparin
• Overlap with LMWH for a minimum of 5 days and
  until INR has been therapeutic for at least 2
  consecutive days
• Unstable angina non-Q-wave MI
• 1 mg/kg BD for 2-8 days
• aspirin 100325 mg/day

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• Low Molecular Weight Heparin
• Any benefits compared with conventional
  intravenous (IV) unfractionated heparin?

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Benefits of LMWH

• Predictable dosing
• Must weigh the patient or calculate LBW
• No monitoring of APTT required
• Can treat in the community as outpatient
• No pump required

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• Low Molecular Weight Heparin
• Risks?

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LMWH No Panacea!

• 7 of QH high risk incidents related to
  enoxaparin!
• Sub-cut vs IV ? not seen as special drug
• Inaccurately promoted as safe alternative to
  heparin because it doesnt need monitoring

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Risks of LMWH
Risks Action




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Risks of LMWH
Risks Action
Must know weight
Must know baseline renal function (CrCl)
Care with dose timing eg peri-procedural
Reversal can be difficult
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LMWH and Renal Impairment

• AVOID if possible!
• Dose adjustment if CrCl lt 30 mL/min
• Prophylaxis 20mg once daily
• Treatment 1mg/kg once daily

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Low Molecular Weight Heparin
Risks Action
Must know weight lean body weight (max 100kg and min 40kg)
Must know baseline renal function (CrCl) lt 30mL/min use IV heparin and monitor APTT
Care with dose timing eg peri-procedural t ½ 12 hrs (care with upcoming surgery or starting post-op)
Reversal can be difficult partially reversed with protamine
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Case Study I

• Dx
• Worsening heart failure, 2o to NSAID and
  sub-optimal therapy
• Weight 70 kg
• Creatinine 180 micromol/L (normally 120)
• Observations
• HR 75
• BP 145/90
• ADR
• penicillin (angioedema? 1999)

• 67 y.o. ?
• Mr AD
• UR 123 456
• DOB 25/02/41
• 32 Pharmy Lane, Drugsville
• Admitted 5 days ago
• SOB, PND
• PMHx
• IHD AMI 98 HF T2DM HT RA

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Prescribing Anticoagulation

• Patient develops DVT
• No thrombophilia found
• Ward round decision
• Start heparin how and what?
• has renal impairment CrCL 30mL/min
• Iv heparin with aptt monitoring

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Heparin Reversal

• Protamine combines with heparin to form a stable,
  inactive complex
• 1mg protamine neutralises 100 units heparin if
  given within 15 min of heparin
• At ? risk of allergic reaction to protamine
• Patients having undergone procedures where
  protamine used, e.g. coronary angioplasty,
  cardiopulmonary bypass
• Diabetics treated with protamine insulin
• Patients allergic to fish
• Vasectomised or infertile men (may have
  antibodies to protamine)

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IV unfractionated heparinKey Messages

• IV indications
• ACS or in place of warfarin maintenance
• e.g. if patient having surgery and warfarin
  stopped
• Surgery
• e.g. Neuro/vascular surgery
• PE/ DVT (as an alternative to LMWH)
• Organise baseline APTT and full blood count
• Check if patient recently prescribed/administered
• enoxaparin / LMWH
• fibrinolytic agent (thrombolysis)
• warfarin and antithrombotics
• Weight adjusted bolus and initial rate of
  infusion based on indication
• For monitoring, use nomogram (based on
  indications)
• Significant inter-patient variability

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Task Initiating Warfarin

• Assess individual benefit vs risk
• Consider age, weight, other Rx, indication,
  duration, co-morbidities.
• Baseline INR to exclude coagulopathy
• Start on first day of heparin therapy
• Overlap warfarin with full heparin dose
• For a minimum of five (5) days and
• INR therapeutic for at least two (2) consecutive
  days

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Warfarin - Key Messages

• Target INR documented?
• Indication specified
• Duration of treatment
• Daily INRs initially subsequent monitoring
• Consider drug interactions
• Patient education imperative
• Warfarin guidelines available for PDA

http//qheps.health.qld.gov.au/qhmms/docs/wafarin_
guidelines_pda.pdf
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Risks of Warfarin

• INR gt 4 10 x bleeding risk vs INR 23
• Bleeds associated with time INR gt target
• Some patients will bleed INR lt 2
• Associated risks
• Anti-platelet therapy
• Change in any medication
• Falls
• Surgery
• Lack of monitoring
• Any illness

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Guidelines

• Risk factors for increased sensitivity to
  warfarin
• Interacting rx
• Hx bleeding
• Baseline INR gt 1.4
• Starting nomogram
• Target INR ranges
• Minimum durations
• Warfarin management peri-operatively
• Warfarin reversal
• Warfarin drug interactions

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Case Study II

• 69 y.o. ? patient with Ca. prostate Hx COPD
• Admitted with bleeding peptic ulcer
• Recent chest infection managed by GP
• UE / LFTs NAD
• Regular Rx (as per discharge 4/12 ago)
• Marevan (warfarin) 2 x 1mg daily (long term for
  recurrent DVTs)
• INR 5.8 (usually stable at 2-2.5, checked
  monthly)
• MS Contin (morphine controlled release) 30mg BD
• Flixotide (fluticasone) MDI, 1 puff BD
• Ventolin (salbutamol) MDI 1-2 Q4-6hrs PRN
• What is going on?

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Key Messages

• INR may increase or decrease for many reasons,
  for example
• Poor concordance/compliance
• Changes to medications
• Drug interactions
• Addition/removal of medicine
• Change in dose

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Case Study II Cont

• GP had started roxithromycin (Rulide) 300mg/day
  for 10 days
• GP concerned with the potential interaction, i.e.
  inhibition of warfarin metabolism, so he checked
  INR day 2 post roxithromycin initiation
• INR ? 2.5
• Effect delayed by 72 hours ? NOT detected by
  day 2 INR!
• NB Augmentin (amoxycillin clavulanate)
• will also potentially raise INR

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Warfarin and Surgery

• Depends on patient and risk
• Low risk (uncomplicated AF)
• Stop 4-5 days prior
• Check INR day of procedure
• Re-start USUAL dose ASAP
• Employ thrombo-prophylaxis as per hospital policy
• High risk SEEK ADVICE
• Cease warfarin 4-5 days prior
• 2-3 days before surgery, commence treatment dose
  of IV heparin or LMWH subcutaneously
• Re-start USUAL dose ASAP (cover with a heparin)
• Cease heparin (IV heparin or LMWH) 48 hours after
  the target INR is reached

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WARFARIN REVERSAL (end of bed chart) WARFARIN REVERSAL (end of bed chart) WARFARIN REVERSAL (end of bed chart)
INR gt therapeutic range but lt 5 and NO bleeding INR gt therapeutic range but lt 5 and NO bleeding withhold review INR and dose
INR 5 9 and NO bleeding INR 5 9 and NO bleeding withhold give vitamin K, 1-2mg orally (0.5-1mg IV) review INR and dose
INR gt 9 and NO bleeding Low risk of bleed withhold give vitamin K up to 5mg orally (0.5-1mg IV) review INR and dose
INR gt 9 and NO bleeding High risk of bleed withhold give vitamin K 1mg IV consider Prothrombinex-HT, FFP review INR and dose
Any clinically significant bleeding where warfarin-induced coagulopathy considered a contributing factor Any clinically significant bleeding where warfarin-induced coagulopathy considered a contributing factor SEEK SENIOR ADVICE cease warfarin give vitamin K 5-10mg IV Prothrombinex-HT, FFP review INR frequently lt 5 and bleeding stops
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Key Messages

• Anticoagulation
• Most frequent high risk drugs you will prescribe
• Assess risks and benefits
• enoxaparin - no panacea
• Need to know renal function, weight, timing
• Prescribing can not be too explicit
• If in doubt, ASK!
• Information available includes
• Guidelines for anticoagulation using warfarin
  (end of bed)
• Heparin Intravenous Infusion Order
  Administration Form
• Your friendly pharmacist!