Practical Antibiotic Prescribing & Antibiotic AwarenessBerny Baretto (Antibiotic Pharmacist)
21st November 2013
Contents
• 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 pre-1940
• Resistance repeatedly followed introduction of new antibiotics
• Resistance greatest where use heaviest
• Resistant mutants selected in therapy
Β-Lactam use & resistance in S.pneumoniae
Bronzwaer et al Emerg Infect Dis. 2002; 8:278-82
Low rates of antibiotic use = low resistance→
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 infection-use 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 MonitoringSep-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
• 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 = (140-age in years) x weight in Kg(from step 1) x F
• clearance 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 :
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
Work out the dosing interval and when levels should be checked
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 antibiotic-practical examples
• 3. Why do we document this- The background
• 4. Audit
• 5. Gentamicin prescribing