Antibiotics Llewelyn Flashcards
How can we reduce the risk of antibiotics resistance?
give patients less antibiotics.
what is giving less antibiotics linked to in terms of clinical outcome?
Reduced risk of mortality with antibiotic de-escalation strategies
what are the key agents which are starting to become resistant?
Gentamicin
Ciprofloxacin
Co-amoxiclav
Piperacillin – tazobactam
what are the 4 key things to consider antibiotic for choice?
- microbial aetiology
- AMR
- Antibiotic knowledge
- Patient factors
what parts make up AMR?
exposure and epidemiology
what makes the microbial aetiology?
focus ‘
exposure
What makes up patient factors?
predisposition
severity
which antibiotics should you know about?
Penicillins Cephalosporins Glycopeptides Aminoglycosides Macrolides Quinolones Metronidazole Tetracyclines Nitrofurantoin Trimethoprim Clindamycin
Define antimicrobial stewardship
a set of coordinated strategies to improve the use of antimicrobial medications with the goal to enhance patient healthoutcomes, reduceantibiotic resistance, and decrease unnecessary costs
how can we revise and review antibiotics better?
Recognise that in hospitals antibiotics are usually started empirically
Think about what evidence you would want to have at review
When you review
Remember antibiotics are harmful
Did they ever have an infection
Are they better now
Do the risks of continuing outweigh the benefits
What is amoxicillin and its MOA and indications?
Amoxicillin is a penicillin.
better activity against some Gram negative bacteria). It is used in the treatment of S. pyogenes infections
Mechanism of action
Inhibition of bacterial cell wall synthesis
what are the features of a type 1 reaction to beta lactam?
Penicillin Allergy – a class effect Immediate / Accelerated – Type 1 (0.02% of courses) 0-72 hours after exposure IgE mediated, mast-cell mediated Urticaria, wheeze, life threatening
what are the features of a delayed reaction?
Delayed – mixed mechanisms (2-3% of courses)
>72 hours after exposure
Will worsen with repeated exposure
Does not become immediate type
what are the features of cephalosporin allergy?
Very complicated – lots of potential haptens involved
Not a class effect
Penicillin X-reactivity more with 1st & 2nd generations
Risk ~8% if previous penicillin allergy
Less with 3rd Generation
give an example of a macrolide, its MOA and indications
Clarythromycin is a macrolide
used for patients with penicillin allergy for treatment of S. pyogenes infections
Mechanism of action
Inhibition of protein synthesis in the bacterial ribosome (50S subunit)
give an example of a glycopeptide, its MOA and indications
and SE
Vancomycin is a glycopeptide. It is active only against Gram-positive bacteria and is active against many resistant strains including Methicillin Resistant S. aureus (MRSA)
Mechanism of action
Inhibits bacterial cell wall (peptidoglycans) formation by a different target to beta lactams
Adverse effects
Nephrotoxic
Ototoxic
give an example of tetracycline, its MOA, indications and SE?
Doxycycline is a tetracycline. Good activity against Gram positives (streps and staphs), some Gram negs (haemophilus). Also active against cell-wall deficient bacteria (e.g. Chlamydia) which cause pneumonia and genitourinary infections.
Mechanism of action
Inhibition of protein synthesis in the bacterial ribosome (30S subunit)
Adverse effects
Dyspepsia
Photosensitivity
Avoid in pregnancy / children (teeth)
what is the MOA of nitrofurantoin, SE and indications?
Nitrofurantoin – a nitrofuran – only important drug in class. Wide spectrum – esp E. coli and some other enterobacteriaceae, also enterococci, staphs, some streps
Mechanism of action
Complex. Damages bacterial DNA
High resistance threshold?
Adverse effects
V well tolerated
Safe in early pregnancy – avoid late
Avoid in renal impairment – peripheral neuropathy, doesn’t penetrate urine if eGFR low
what is 1st line antibiotics for CAP?
amoxicillin
what is 1st line antibiotics for HAP?
Co-amoxiclav
what is 1st line for meningoencephalitis?
ceftriaxone and dexamethasone
what is the 1st line for cellulitis ?
flucloxacillin
what is 1st line for abdominal sepsis?
cefotaxime
