1. Practical Antibiotic Prescribing & Antibiotic Awareness
Berny Baretto (Antibiotic Pharmacist)
5th February 2015

2. Contents Antibiotic Awareness Why is it important?- Background
How to prescribe an antibiotic
New Antibiotic Policy 2015
Audit
What must be included in an antibiotic prescription
Practical examples
Gentamicin Prescribing
Summary

3. European Antibiotic Awareness Day- campaign to promote prudent antibiotic use(18th November 2014, supported by DOH)

4. 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

5. 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

6. Β-Lactam use & resistance in S.pneumoniae→
Low rates of antibiotic use = low resistance
Bronzwaer et al Emerg Infect Dis. 2002; 8:278-82

7. 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

8. 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

9. Then Focus is:
Review clinical diagnosis and the continuing 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.

11. Prompt I/V to oral switch
All I/V antibiotics should be reviewed at 48 hours and changed to oral where clinically appropriate.
Advantages
It reduces the likelihood of I/V related infections
It reduces potential discomfort for patients on I/V therapy.
It allows more timely administration of antibiotics for the patient.
It helps to facilitate a prompt discharge for patients
It is quicker for administration, saving nursing time and therefore there is a potential cost saving too.
It potentially reduces overall treatment costs

12. Department of Health Guidance-Antibiotic Stewardship

13. 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

14. New Antibiotic Policy 2015
1. New allergy section eg abdominal infections: cholangitis
2. Oral switch/stepdown
Eg SBP in cirrhosis
Piperacillin/tazobactam 4.5g tds i/v →co-amoxiclav 625mg tds po
Standard treatment
Penicillin
allergy
Penicillin anaphylaxis
Pip/taz 4.5g tds i/v
Meropenem 1g tds i/v
Cipro 500mg bd po+ met 500mg tds i/v

15. Other Guidelines 1. Neurosurgical guidelines 2. Use of gentamicin
3. Use of teicoplanin
4. Use of vancomycin
(linked to main policy)
5. Clostridium difficile
6. Prophylaxis Policy
(separate Policies)

16. Clostridium difficile guideline
1. Information on diagnosis and laboratory findings(interpretation of test results)
2. General considerations
Stop antibiotics, review PPIs, fluid balance etc
3. Treatment options
Metronidazole use -1st line
High dose vanc (orally)

17. Prophylaxis Policy
Antibiotic prophylaxis at an appropriate dose and time reduces the frequency of surgical site infections.
For optimum efficacy, intravenous antibiotics should be administered within 60 minutes of the skin being incised and as close to time of surgical incision as practically possible.
Single doses of antibiotics must be prescribed for surgical prophylaxis where antibiotics have been shown to be effective.
A repeat dose of antibiotic is required in prolonged procedures and where there is significant blood loss.

18. Quarterly Audit-(overall Trust Data)
General Antibiotic Data
Dec-13
Mar-14
Jun-14
Sep-14
% Patients on antibiotics
36%
30%
31%
29%
% IV Antibiotics
57%
58%
62%
% Oral Antibiotics
43%
42%
38%

19. Specific Antibiotic Monitoring
Dec-13
Mar-14
Jun-14
Sep-14
%i/v >48hrs
56%
57%
51%
50%
%>5days but ≤ 7 days
10% 8%
% > 7 day course
14%
15%
12%
% > 7 day course appropriate
100%
95%
98%
% Patients with allergy status documented
90%
78%
85%
86%
% Indication stated
70%
73%
76%
84%
% antibiotics prescribed appropriately when indication stated
99%
93%
% course length or review stated
48%
53%
58%
63%

20. PRACTICAL EXAMPLES

21. What must be included in an antibiotic prescription-Documentation of allergy status

22. UTI Recommendation

23. Uncomplicated Cystitis

24. Crossing off an Antibiotic

25. Re-prescribing after antibiotic sensitivities appear on CRRS

26. Chest Infection Recommendation

27. Query Non-severe CAP

28. 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).

29. 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 ≥BMI 30 use formula for dosing weight.-see below.

30. 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) = (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 (≥BMI 30) use obese dosing weight calculation5 :
Obese Dosing Weight (in Kg) = ideal body weight (actual Body weight – ideal body weight)

31. 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 (≥BMI 30)- use obese dosing weight
c) if weight unobtainable – calculate ideal body weight

32. 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)

33. 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
21-40ml/min
48 hourly
Before 2nd dose
< 21ml/min
> 48 hourly
Check level after 48 hours

34. 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, check guideline for further information regarding interpretation or consult Microbiology/ Pharmacy for advice.

35. Documentation on Medicine Chart

36. SUMMARY 1. Antibiotic Awareness
2. What to include when prescribing an antibiotic-practical examples
3. Why do we document this- The background
4. New Antibiotic Policy 2015
5. Antibiotic Audit
6. Gentamicin prescribing