2 Safe prescribing a case study
Download
Report
Transcript 2 Safe prescribing a case study
SAFE AND EFFECTIVE
PRESCRIBING - 2
Safe prescribing a case study and
Anticoagulation 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
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
Latent factors
Organisational/ Management– work load, hand written prescriptions, staffing
Culture of lack of support for interns
Lack of safety training and awareness of risks as undergraduate
To recap – why interns make mistakes
Error-producing factors
Environmental – busy ward, interruptions
Team – lack of supervision, hierachy
Individual – limited knowledge, information
Task - repetitious, poor medication chart design
Patient – complex, communication difficulties
Active failures
Error – slip, lapse or Violation
Defenses
Inadequate –
Guideline confusing
No pharmacist
Harm
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)
Severe anaphylaxis, dialysis,
steroids, antihistamines Prepared by Nurse 1 (busy)
Check Nurse 2 (agency)
Patient (asleep)
Given
by RN
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
Information
Retrieval –
Presenting
complaint,
History, Lab
Monitoring
and review
Patient
Decision re,
Drug, route,
dose vs
Patient,
disease,
drugs
Mainly Snr
doctors
Instruction to:
prescribers,
pharmacists,
nurses
7
Mainly Jnr Doctors
And or nursing staff
Coombes I, PhD
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
Physically block further
administration
Prevent transcription errors
but still legible for records
Sign and Date,
reason for ceasing
State
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!
Heparins
Low Molecular Weight Heparin (LMWH)
Standard Unfractionated Heparin
Heparinoids (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?
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)
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
Initial
Treatment
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 required
Can 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
Must know weight
Must know baseline renal
function (CrCl)
Care with dose timing eg
peri-procedural
Reversal can be difficult
Action
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
Must know weight
Action
lean body weight (max 100kg and
min 40kg)
Must know baseline renal < 30mL/min = use IV heparin and
function (CrCl)
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:
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
- IHD; AMI ’98; HF; T2DM; ADR
HT; RA
- 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
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
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 withhold
< 5 and NO bleeding
review INR and dose
INR 5 – 9 and NO bleeding
withhold
give vitamin K, 1-2mg orally (0.5-1mg IV) review
INR and dose
INR > 9
and NO
bleeding
Low risk of
bleed
withhold
give vitamin K up to 5mg orally (0.5-1mg IV)
review INR and dose
High risk of
bleed
withhold
give vitamin K 1mg IV
consider Prothrombinex™-HT, FFP
review INR and dose
Any clinically significant
bleeding where warfarininduced coagulopathy
considered a contributing
factor
SEEK SENIOR ADVICE
cease warfarin
give vitamin K 5-10mg IV
Prothrombinex™-HT, FFP
review 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!