Antibiotics Flashcards
What are common side effects of betalactams?
Rash
Diarrhoea
Seizures
Interstitial nephritis
How do carbapenems work? What is a common one?
Beta lactam that binds PBP
Meropenem
What are the implications of amoxicillin and ampicillin’s chemical difference from benzylpenicillin?
They are slightly more resistant to beta-lactamase
What are some common 4th gen cephalosporins?
Cefepime
Which organisms are covered by benzylpenicillins?
Most streps - Grp A, pneumoniae
Most enterococci
5% of Staphs
No gram -ve
What must you consider when prescribing ciprofloxacin?
There is low genetic barrier to resistance there attempt to reduce bacterial load prior to use eg IV penicillin, or surgical debridement
What organisms does ciprofloxacin cover?
Pseudomonas
Other gram -ves
What is the organism coverage of 1st gen cephalosporins?
Staphs and streps
A little gram neg
What do 5th gen cephalosporins cover?
Pseudomonas
MRSA
Enterococcus
Why aren’t ampicillin and amoxicillin necessarily better than benzylpenicillin?
Rash is 10x more common
Diarrhoea is also more likely
Rash occurs in 80-90% when there is glandular fever present
What is a common 2nd gen cephalosporin?
Cefuroxime
What is the mode of administration of phenoxymethylpenicillin?
Oral
What organisms do flucloxacillin and dicloxacillin cover?
Methicillin sensitive Staphs
Streps
What type of antibiotic is clindamycin? How does it work?
Lincosamide
Bacteriostatic
Inhibits protein synthesis by binding to the 50S ribosomal subunit
What is the mechanism of action of quinolones?
Bacteriocidal
Inhibit DNA synthesis by inhibiting DNA gyrase and topoisomerase
What is the name of a 5th gen cephalosporin?
Ceftaroline
What are the common 1st gen cephalosporins?
Cephazolin
Cephalexin
What is the commercial name of piperacillin + tazobactam?
Tazocin
How are betalactams excreted?
Renally
What is the antibiotic of choice for UTIs?
Trimethoprim
What is the mechanism of action for cephalosporins?
Inhibit cell wall synthesis by binding to penicillin-binding proteins
When should aminoglycosides be used?
Very rarely due to risk of severe sides effects - ototoxicity, vestibular toxicity, renal toxicity
Enteroccocal endocarditis at low dose (1mg/kg) a penicillin eg amoxicillin
What are the indications for benzylpenicillins?
Pneumonia
Skin and soft tissue infections
Rheumatic fever
Pharyngitis
What do carbapenems cover? When are they indicated?
Streps and staph (not MRSA)
Pseudo and gram -ves
Used in resistant organisms
When are amoxicillin and ampicillin indicated?
Same as benzylpenicillins
- Pneumonia
- Skin and soft tissue infections
- Rheumatic fever
- Pharyngitis
What is the name of a commonly used quinolone?
Ciprofloxacin
Which cephalosporins can be used against pseudomonas?
4th and 5th gen
What are the indications for microlides?
Intracellular infections eg legionella, chlamydia
Which organisms do amoxicillin and ampicillin cover?
Streps - Grp A and pneumoniae
Enterococci
5% of Staphs
30% of E. coli and some gram negatives
What is timentin?
Ticarcillin and Clav
What are some indications for tetracyclines and what is a common one?
Intracellular infections
Malaria
Acne
Doxycycline
What is a third gen cephalosporin?
Ceftriaxone
What is the triple therapy for H. pylori?
Clarithromycin
Amoxicillin
PPI
When is clindamycin usually used? What microbes does it cover?
As an alternative in patients with severe allergy to penicillins and cephalosporins
Has good Staph and Strep cover
What side effects do microlides cause?
Long QT
Liver interactions - eg warfarin
What type of antibiotic is cefazolin?
1st Generation cephalosporin
How do amoxicillin and ampicillin differ in the modes of administration?
Ampicillin is IV
Amoxicillin is oral
What is the indication for ceftriaxone?
Empirical treatment for severe pneumonia
Bacterial meningitis
Septicaemia
What is augmentin duofort?
Amoxicillin with clavulanic acid
What is ceftriaxone?
A third generation cephalosporin
What are some common microlides?
Azithromycin, roxithromycin
What organisms do third gen cephalosporins cover
Streps
Range of gram -ves
No pseudomonas
What is the mechanism of action of tetracyclins?
Inhibit DNA synthesis
What the indication for augmentin duofort?
Hospital acquired pneumonia
UTIs
Acute cholecystitis (after IVs)
How is benzylpenicillin administered?
IV or IM
What is an adverse effect of clindamycin?
Toxic epidermal necrolysis
Taste disturbance
C. difficile infection
How does the coverage of 2nd gen cephalosporins differ from 1st gen?
Loose some staph cover
Gain some gram -ve cover
When is ciprofloxacin indicated?
Bone or joint infection
Complex UTI
P. aeruginosa infection
What is the scientific name for penicillin G?
Benzylpencillin
Which organism do 4th gen cephalosporins cover and when are they indicated?
Pseudomonas
Streps
Gram negs
Mainly reserved for pseudomonas
What organisms do third generation cephalosporins target?
A broad range of gram positives and some gram negatives
