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A Vitamin T Overdose? : An audit of piperacillin/
tazobactam use at Royal Perth Hospital
Amelia Davis and Matthew Hanson
Contributors: Dr Susan Benson, Dr Owen Robinson, Matthew Rawlins
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Background

Piperacillin/ tazobactam (commonly: Tazocin)

4g + 0.5g tds

B lactam + B lactamase inhibitor

Broad spectrum: gram positive, gram negative* and anaerobes*

Largely replaced ticarcillin/clavulanate (Timentin) in 2010
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“Unrestricted”
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Introduction


Restrictions for other antibiotics:

Broad spectrum cephalosporins

Carbapenems

Glycopeptides

Flouroquinolones
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Others
Lack of specific guidelines or restrictions for piperacillin/
tazobactam
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Purpose

Review the indications and appropriateness of piperacillin/
tazobactam
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Attempt to highlight hospital specific factors influencing
prescribing
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Methods
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A cross sectional, point prevalence study



National Antimicrobial Prescribing Survey
571 inpatients at Royal Perth Hospital on 14/11/12
To quantify and analyse the use of antimicrobials

Identified patients on piperacillin/ tazobactam (n=78)
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Recalled patient notes

Recorded indication for antibiotic, diagnosis, frequency of
administration and prescribing department

All non-concordant prescriptions reviewed by two ID
Physicians
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Methods
Category
C- Concordant with guidelines
NC(A)- Non- concordant with guidelines but deemed
Appropriate by ID review
NC (IA) – Non- concordant with guidelines (Inappropriate
choice)
F- Correct Choice but incorrect frequency
Where C= Concordant with therapeutic
guidelines or RPH guidelines
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Results
Overall
Category
Number of Patients
(n=78)
C- Concordant with guidelines
25 (32%)
NC(A)- Non- concordant with
guidelines but deemed
Appropriate by ID review
19 (24%)
NC (IA) – Non- concordant with
guidelines (Inappropriate choice)
34 (44%)
F- Correct Choice but incorrect
frequency
4 (5%)
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Results
Category C – Concordant with guidelines
Indication
Peritonitis
Diabetic Ulcer
Contaminated Wound
Animal/Human Bite
Aspiration Pneumonia
HAP – high risk
Febrile Neutropaenia
Necrotising Pancreatitis
Number (n=25)
9
4
3
3
3
1
1
1
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Results
Category NC(A) – Not concordant with
guidelines but deemed an appropriate
choice by ID Physicians
Indication
Abdominal infections
Skin infections
Respiratory infections
Urinary tract infections
Abdominal infections included:
• appendicitis
• cholecystitis
• abscess
• fistulae
• bowel necrosis
• non-specific infective surgical abdomen
Number (n=19)
12
3
2
2
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Results
Category NC(IA) – Not concordant with
guidelines – inappropriate choice
Indication
Poor antibiotic
reasoning (47%)
No indication for antibiotic
“Febrile Neutropaenia” (not
meeting criteria for
neutropaenia)
Prolonged post-surgical
prophylaxis
Unnecessary broad CAP
spectrum of action Empirical UTI
(53%)
Cellulitis
Wound infection – without
systemic symptoms
Number
(n=34)
11
3
2
6
4
2
2
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Breakdown by department

Appropriate
Not
Appropriate
Medical
12
20
Surgical
32
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Chi- squared test
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P= 0.0049
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Statistically significant difference between medical and surgical
teams
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Frequency/Dose
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Frequency
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3 incidences of bi- daily dosing
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1 incidence of alternate day dosing
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All documented to be due to “renal impairment”
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None actually met criteria for reduced dosing (GFR <20ml/min)
Dosing
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All 78 prescriptions 4 + 0.5g
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Limitations
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Cross sectional, retrospective study
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Sample size
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Poor documentation
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Did not formally analyse duration of therapy
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Conclusions
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What we do well
 Piperacillin/ tazobactam was appropriate in 56%

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Common appropriate indications:
 Peritonitis
 Diabetic ulcers
What we don’t do so well
 Piperacillin/ tazobactam was inappropriate in 44%
 Poor antibiotic reasoning
 Unnecessary use of broad spectrum
 Documentation
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Further Questions Raised?
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Why are we prescribing inappropriately?
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Over treating?
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Medical vs Surgical?
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Restricted use of other antibiotics?
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Concern about risk of toxicity with aminoglycosides use?
What do we do now?
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Education re: common inappropriate uses
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Improve documentation
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Questions?