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

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

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

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 → 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 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 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.

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

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

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

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)

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)

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.

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%

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%

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 ≥BMI 30 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 (≥BMI 30) 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 (≥BMI 30)- 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 : 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

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.

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. New Antibiotic Policy 2015 5. Antibiotic Audit 6. Gentamicin prescribing