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