2b. Antibiotics - Michelle Wong · Antibiotic Prescribing Tips Allergy box completed Antibiotic,...

Michelle WongLead Antimicrobial Pharmacist

Antibiotics

Aims and Objectives

How to access the Antimicrobial Formulary What is expected for every antibiotic

prescription MCQs Audit

What are the signs of infection?

Systemic– Fever, rigors, delirium, chills, myalgia, headache,

anorexia, malaise Peripheral/local

– Erythema, pain, heat, swelling, pus Vital signs

– Temperature, tachycardia, hypotension, tachypnoea

Is an antibiotic indicated?

Evidence of infection– Clinical signs/symptoms– Laboratory

Biochemistry Haematology Microbiology – previous results are very important

– Medical imaging SAMPLE SAMPLE SAMPLE – allows for

targeted therapy

Empirical therapy

Grenade vs sniper approach

Broad vs narrow spectrum antibiotics

Broad spectrum antibiotics

– Co-amoxiclav– Quinolones– Cephalosporins– Tetracyclines– Macrolides– Piperacillin/tazobactam– Meropenem

Narrow spectrum antibiotics

– Trimethoprim– Benzylpenicillin/Phenoxymethylpenicillin– Flucloxacillin– Fusidic acid– Vancomycin – Gentamicin

General drug selection criteria

Age, weight (especially extremes), gender Cautions/contraindications

– Allergy (nature – to establish true allergy – cost of allergy, if penicillin- explore previous cephalosporins/carbapenem use), ADR, pregnancy/breastfeeding

Renal and hepatic function Interactions – e.g antibiotics and warfarin,

oxycodone and clarithromycin Route and bioavailability Dose, frequency, duration

What antibiotic information is available?

Antimicrobial Formulary for adults and paediatrics available on the Intranet

AM apphttp://www.bfwh.nhs.uk/mobile/amformulary/index.shtml

Vancomycin and gentamicin dosing guidelines Gentamicin calculator for treatment initial doses:

http://fcvmsrv243/gentcalc/ Surgical prophylaxis guidelines Contact consultant microbiologists for antibiotic advice Ward pharmacists BNF

Antibiotic Prescribing Tips

Allergy box completed Antibiotic, route, dose and frequency Review date at 48 hours – sign and GMC number Stop date (5 days if empiric) Use the shortest duration of treatment suitable for

the infection Indication recorded on prescription chart, as well as

medical notes IV antimicrobials review after 48 hours – to oral? Printed Name and bleep number

Antibiotic Prescribing Tips

Change from IV to oral guide CHORAL Microbiological specimens Time is essential Management of MRSA/CPE – contact

microbiology Dosing in Renal Impairment Antimicrobial prophylaxis post-splenectomy

Prescribing Tips

RAG antibiotics list Don’t forget incision and drainage/surgical

intervention may be the only option

Start smart then focus

CQUIN 2018-19

24-72hours review and document outcome and new stop/review date– Stop – Continue– Switch – escalate/de-escalate, as per culture– IV to Oral– OPAT

If to remain on IV AB – state reason

NBM/malabsorption No oral AB alternative Not clinically improving Deep seated infection Based on microbiology, infection pharmacist

advice

Is this OK?

Good example

?Appropriate choice for UTI

Amoxicillin Resistance – January 2013 to December 2016

(% formulated using Resistant and Sensitive results on gram negative organisms.)

Trimethoprim Resistance – January 2013 to December 2016

(% formulated using Resistant and Sensitive results on gram negative organisms.)

Nitrofurantoin Resistance – January 2013 to December 2016

(% formulated using Resistant and Sensitive results on gram negative organisms.)

Sample sensitivity review

MUST review relevant previous/current sample sensitivity

High risk antibiotics for C difficile

Co-amoxiclav Cephalosporins (especially 2nd/3rd

generations) Ciprofloxacin (quinolones) ?Clindamycin (high dose used at BTH as

protective effect to CDT) Not same as clarithromycin

GDH + & C. Difficile + Patients

GDH – Glutamate Dehydrogenase

GDH –ve GDH +ve + C. Diff toxin –ve GDH +ve and C. Diff toxin +ve

Therapeutic Drug Monitoring

Glycopeptide

1st choice – vancomycin Used intravenously for MRSA infections,

alternative to penicillins for gram positive cover

Requires renal function and therapeutic drug monitoring

Max rate of administration 10mg/min Oral - not absorbed Teicoplanin higher dose used –no routine

level

Vancomycin Monitoring + sheet coming soon

Aminoglycoside

Gentamicin, tobramycin, amikacin Nephrotoxic and ototoxic Mainly use once daily except for infections

e.g. endocarditis Requires renal function and therapeutic drug

monitoring High level – don’t ignore it-review it Rarely used for longer than 48-72hours

except for endocarditis Extremes of weight – contact pharmacy

Gentamicin monitoring

80 year old male, 80kg (not obese)

Urosepsis Creatinine

112micromole/L (CrCl 53ml/min)

Gentamicin level at 9:00am 2/1/12 = 3.1mg/l

What do you do?

Gentamicin monitoring

Taken too early - insignificant Should be taken 1-4 hours before the 2nd

dose Repeat level at ~6-9pm Nursing to document time of administration

and time of sample in the medical notes

Key top interactions…

Antifungals/quinolones/rifamycins – LOTS of interactions!

Most antimicrobials – Warfarin Macrolides/Daptomycin/Fusidic Acid –

Statins Daptomycin – Measure CK Trimethoprim – Methotrexate Aminoglycosides – IV diuretics

Clarithromycin and oxycodone/fentanyl patch

Clarithromycin is strong CYP3A4 inhibitors INHIBITOR interaction is SIGNIFICANT May increase the concentration of

oxycodone/fentanyl Major incidents in real patients at BTH with

respiratory depression needing reversal with naloxone

Audit

Data on compliance with the antibiotic formulary done quarterly.

If interested in participating in an audit contact antimicrobial pharmacist/microbiologist

Any questions???Good luck