safe and effective prescribing - 2 safe prescribing a case study and anticoagulation key messages dr...
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SAFE AND EFFECTIVE PRESCRIBING - 2
Safe prescribing a case study andAnticoagulation key messages
SAFE AND EFFECTIVE PRESCRIBING - 2
Safe 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
Dr Ian Coombes,
Senior Clinical Lecturer University of Queensland Schools of Medicine and Pharmacy
Safe Medication Practice Unit, Queensland Health
The University of Queensland
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
To recap – why interns make mistakes
Harm
Latent factorsOrganisational/ Management– work load, hand written prescriptions, staffing
Culture of lack of support for internsLack of safety training and awareness of risks as undergraduate
Error-producing factorsEnvironmental – busy ward, interruptions
Team – lack of supervision, hierachyIndividual – limited knowledge, information
Task - repetitious, poor medication chart designPatient – complex, communication difficulties
Active failuresError – slip, lapse or Violation
DefensesInadequate –Guideline confusing
No pharmacist
How a patient with documented ADR to cephalosporin received two more doses
{From Reason’s 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)
Prepared by Nurse 1 (busy)
Check Nurse 2 (agency)
Patient (asleep)
Given
by RN
Severe anaphylaxis, dialysis, steroids, antihistamines
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
So What is a Prescribing?
The Prescribing process
Patient
Coombes I, PhD7
Mainly Snrdoctors
Mainly Jnr DoctorsAnd or nursing staff
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
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
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
Your Registrar asks you to write up Mr AD’s drug chart
(DOB: 01/4/40; UR:155566; 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
Write up the medicines the person should have
Pass to the Person Next to You
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?
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
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
Sustained release drugs
What if the patient gets 4 x 60 mg tablets ?
Hypotensive = bradycardic
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
Ceasing Medications
Prevent transcription errorsbut still legible for records
Physically block further administration
Sign and Date, State reason for ceasing
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
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 ?
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!
Anticoagulants - Objectives Anticoagulation
Why, where, when and when NOT to!
HeparinsLow Molecular Weight Heparin (LMWH)Standard Unfractionated HeparinHeparinoids (eg danaparoid)
Warfarin Anticoagulation and Surgery Reversal
Anticoagulation: The classic balance between risk and benefit of
medication
The margin for error is relatively small
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
Anticoagulation
Indications?
Primary prevention:Atrial Fibrillation (AF), left ventricular dilatation, mural
thrombusDVT/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)
Indications for anticoagulation?
Anticoagulation
Contraindications?
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
Anticoagulation
Prophylaxis Treatment
Initial Mostly fractionated heparin Occasionally unfractionated heparin Very occasionally warfarin (eg AF)
Subsequent Mostly warfarin Occasionally heparin if warfarin contraindicated (eg pregnancy)
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
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 100–325 mg/day
Low Molecular Weight Heparin
Any benefits compared with conventional intravenous (IV)
unfractionated heparin?
Benefits of LMWH
Predictable dosing Must weigh the patient or calculate LBW
No monitoring of APTT requiredCan treat in the community as
outpatient No pump required
Low Molecular Weight Heparin
Risks?
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 “doesn’t need monitoring”
Risks of LMWH
Risks Action
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
LMWH and Renal Impairment
AVOID if possible!Dose adjustment if CrCl < 30 mL/min- Prophylaxis: 20mg once daily- Treatment: 1mg/kg once daily
Low Molecular Weight Heparin
Risks Action
Must know weightlean body weight (max 100kg and min 40kg)
Must know baseline renal function (CrCl)
< 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
Case Study I
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
Dx- Worsening heart failure, 2o to
NSAID and sub-optimal therapy
Weight: 70 kgCreatinine: 180 micromol/L
(normally 120)
Observations- HR 75- BP 145/90
ADR- penicillin (angioedema? 1999)
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
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)
IV unfractionated heparin
Key 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
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
Target INR – documented? Indication specified Duration of treatment Daily INRs initially – subsequent monitoring Consider drug interactions Patient education imperative Warfarin guidelines available for PDA
Warfarin - Key Messages
http://qheps.health.qld.gov.au/qhmms/docs/wafarin_guidelines_pda.pdf
Risks of Warfarin
INR > 4 ≈ 10 x bleeding risk vs INR 2–3 Bleeds associated with time INR > target Some patients will bleed INR < 2 Associated risks:
- Anti-platelet therapy-Change in any medication- Falls- Surgery- Lack of monitoring- Any illness
Guidelines
Risk factors for increased sensitivity to warfarin- Interacting rx-Hx bleeding- Baseline INR > 1.4
Starting nomogram Target INR ranges Minimum durations Warfarin management peri-operatively Warfarin reversal Warfarin drug interactions
Case Study II
69 y.o. ♂ patient with Ca. prostate + Hx COPD Admitted with bleeding peptic ulcer Recent chest infection managed by GP U&E / 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?
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
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
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
WARFARIN REVERSAL (end of bed chart)
INR > therapeutic range but < 5 and NO bleeding
withholdreview INR and dose
INR 5 – 9 and NO bleeding withholdgive vitamin K, 1-2mg orally (0.5-1mg IV) review INR and dose
INR > 9 and NO bleeding
Low risk of bleed
withholdgive vitamin K up to 5mg orally (0.5-1mg IV) review INR and dose
High risk of bleed
withholdgive vitamin K 1mg IVconsider Prothrombinex™-HT, FFPreview INR and dose
Any clinically significant bleeding where warfarin-induced coagulopathy considered a contributing factor
SEEK SENIOR ADVICEcease warfaringive vitamin K 5-10mg IVProthrombinex™-HT, FFPreview INR frequently < 5 and bleeding stops
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!