Transcript How to prescribe an antibiotic

Practical Antibiotic Prescribing &
Antibiotic Awareness
Berny Baretto (Antibiotic Pharmacist)
21st November 2013
Contents
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Antibiotic Awareness Day-18th November 2013
How to prescribe an antibiotic
Why is it important?
Background
Audit
What must be included in an antibiotic prescription
Practical examples
Gentamicin Prescribing
Summary
European Antibiotic Awareness Day- campaign
to promote prudent antibiotic use(supported by
DOH)
European Antibiotic Awareness Day
18 November 2013
Key Messages
• It is a public health initiative aimed at encouraging
responsible use of antibiotics
• Lack of new antibiotics being developed especially to
cover gram negative bacteria.
• Number of infections due to antibiotic–resistant bacteria
is growing
• Important to preserve the use of the antibiotics currently
available eg carbapenems
Background contd-Use selects
Resistance
• Acquired resistance absent from bacteria collected pre1940
• Resistance repeatedly followed introduction of new
antibiotics
• Resistance greatest where use heaviest
• Resistant mutants selected in therapy
Β-Lactam use & resistance in
S.pneumoniae
→
Low rates of antibiotic use = low
resistance
Bronzwaer et al Emerg Infect Dis. 2002; 8:278-82
How to prescribe an antibiotic –why is it
important
• Department of Health Guidelines-(Advisory Committee on
antimicrobial resistance and healthcare associated Infection)-Nov
2011
• Antimicrobial stewardship- “start smart-then focus”• Want :
• Right Drug
• Right Dose
• Right Time
• Right Duration
• For Every Patient
Start Smart Is :
• Don’t start antibiotics in the absence of clinical evidence
of bacterial infection
• If there is evidence or suspicion of bacterial infectionuse local antibiotic guidelines to start treatment
• Document on drug chart Indication, duration/review
date, route & dose
• Obtain cultures first
• Prescribe single dose antibiotics for surgical
prophylaxis-where proven efficacy
Then Focus is:
• Review clinical diagnosis and the coninuing need for antibiotics by
48 hours and make a clear plan of action- “the antimicrobial
prescribing decision”
• 5 options
• 1. STOP
• 2. Switch i/v to oral
• 3. Change –ideally to narrower spectrum or broad if needed
• 4. Continue (review again at 72 hours)
• 5. Outpatient Parenteral antibiotics therapy (OPAT)
• Make sure review and decision is clearly documented in medical
notes.
Department of Health Guidance-Antibiotic
Stewardship
Good Prescribing Practice
• Promotes Good Prescribing Practice- no missed doses,
ensures continuity in care
• Adherence to Trust Antibiotic Policy
• Helps to Reduce Incidence of Clostridium difficile
Infection
• Audit
Quarterly Audit-(overall Trust Data)
General
Antibiotic
Data
Sep-12
Dec-12
Apr-13
July-13
% Patients
on
antibiotics
30%
32%
34%
32%
% IV
Antibiotics
56%
51%
47%
63%
% Oral
Antibiotics
44%
49%
53%
37%
Specific Antibiotic Monitoring
Sep-12
Dec-12
Apr-13
Jul-13
%i/v >48hrs
47%
58%
55%
46%
%>5days but ≤ 7
days
13%
7%
11%
6%
% > 7 day course
12%
15%
18%
15%
% > 7 day course
appropriate
80%
98%
97%
100%
% Patients with
allergy status
documented
86%
86%
86%
86%
% Indication
stated
67%
64%
69%
71%
% antibiotics
prescribed
appropriately when
indication stated
98%
95%
96%
99%
% course length
or review stated
50%
58%
51%
53%
• PRACTICAL EXAMPLES
What must be included in an antibiotic
prescription-Documentation of allergy status
UTI Recommendation
Uncomplicated Cystitis
Crossing off an Antibiotic
Re-prescribing after antibiotic
sensitivities appear on CRRS
Chest Infection Recommendation
Query Non-severe CAP
Gentamicin Prescribing
• 5 steps for safe gentamicin
prescribing
• Usually gentamicin is only required for 24-48hrs.
• Course lengths for gentamicin should not exceed 5
days unless Microbiology have approved its use for
extended durations (this may be indicated in some
infections eg Endocarditis).
1. Weigh Patient:
• Weigh patient. If weighing is not possible, estimate
weight using ideal body weight formulae (based on
height and gender).
• For obese patients >120% ideal body weight use
formula for dosing weight.-see below.
Equations for Ideal Body weight and Obese
dosing
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Imperial
Ideal Body weight (Male) = 50 + (2.3 x inches over 5 feet)
Ideal Body weight (Female) = 45.5 + (2.3 x inches over 5 feet)
Or
Metric
Ideal Body weight (Male) = 50kg + 0.9kg for each cm above 150cm in
height
• Ideal Body weight (Female) = 45.5Kg + 0.9kg for each cm above 150cm
in height
• For Obese Patients (> 120% of ideal body weight) use obese dosing
weight calculation5 :
• Obese Dosing Weight (in Kg) = ideal body weight + 0.4 (actual Body
weight – ideal body weight)
2. Calculate gentamicin Dose :
• Calculate the gentamicin dose using 5mg/Kg
(maximum 400mg od)
• a)If normal body weight - use actual body weight
value
• b)If Obese (> 120% of ideal body weight)- use obese
dosing weight
• c) if weight unobtainable – calculate ideal body weight
3. Calculate creatinine clearance (CrCl) :
• Calculate the creatinine clearance using Cockcroft and Gault equation
• Creatinine =
• clearance
(140-age in years) x weight in Kg(from step 1) x F
Serum Creatinine (in micromole/Litre)
• F=1.04 (female) or F=1.23 (male)
4. Check dosing Interval and when levels
need to be done :
Work out the dosing interval and when levels should be checked
Creatinine
Clearance
Dose Interval
Pre-dose level
check
> 60ml/min
24 hourly
Before 2nd/3rd dose
41-60ml/min
36 hourly
Before 2nd/3rd dose
21-40ml/min
48 hourly
Before 2nd dose
< 21ml/min
> 48 hourly
Check level after
48 hours
5. Check gentamicin serum level
• If pre-dose gentamicin level is 1mg/L or less continue
the original dosing regime
• If pre-dose gentamicin level is greater than 1mg/L,
consult Microbiology or Pharmacy for advice.
Documentation on Medicine Chart
SUMMARY
• 1. Antibiotic Awareness
• 2. What to include when prescribing an antibioticpractical examples
• 3. Why do we document this- The background
• 4. Audit
• 5. Gentamicin prescribing