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!