Antibiotics Flashcards
What does clindamycin target?
Clindamycin Inhibits protein synthesis. It targets the 50s subunit of the ribosome and prevents ribosomal translocation so is only bacteriostatic.
What class of antibiotic is clindamycin in?
Clindamycin is a lincosamide.
What is clindamycin used for?
Mostly gram positive infections and anaerobic infections.
It cannot penetrate well into gram negative bacteria.
Often used for MRSA/MSSA skin infections and bone and joint infections.
Sometimes used to treat malaria.
May be used in combination with Vancomycin for TSS as it inhibits release of toxins.
What adverse effects can clindamycin cause?
It can be hepatotoxic as is excreted by the liver.
Clindamycin is associated with CDAD.
Should not be given in combination with macrolides or chloramphenicol as will antagonise.
What class of antibiotic is Erythromycin and what does it target?
Erythromycin is a macrolide antibiotic. It targets the 50s ribosomal subunit preventing ribosomal translocation, inhibiting protein synthesis. It is bacteriostatic.
Name four macrolide antibiotics
Erythromycin
Azithromycin
Clarithromycin
Spectromycin
What is the spectrum of erythromycin?
Targets gram pos staphs and streps, limited gram negatives (no coliforms) and anaerobes.
What is erythromycin used for?
Often used in patients who are allergic to penicillin as has a similar spectrum.
RTIs - targets legionella and mycoplasma/ atypical RTIs as well.
What are the adverse effects of erythromycin?
It is excreted by the liver so can be hepatotoxic.
It can also cause nausea and a rash.
Name 3 quinolone antibiotics
Ciprofloxacin
Levofloxacin
Nalidixic acid
What target does ciprofloxacin have?
It targets DNA gyrate preventing unwinding of DNA strands during replication.
What is the spectrum of ciprofloxacin?
Gram neg mostly and some gram positives.
What syndromes is ciprofloxacin mostly used for?
Uti’s
Osteomyelitis
CAP
Gastroenteritis
What side effects of ciprofloxacin are there?
Nausea
Vomiting
Cartilage erosion in young
CDAD
How can ciprofloxacin be administered?
IV or orally
It is the only oral antibiotic effective against pseudomonas
Name a sulphonamide
Co-trimoaxazole
Trimethoprim-sulphamethoxazole
What is Bactria and what is it used for?
Co-trimoaxazole
Mainly UTI’s
What does chloramphenicol target?
It targets the 50s subunit - bacteriostatic
What is the spectrum of chloramphenicol?
Broad
G+ve, g-ve and anerobic
Can be give IV, orally or topically
Can enter CSF
What side effects does chloramphenicol have?
It can cause bone marrow suppression so has restricted uses.
What class is daptomycin in?
It is a lincosamide.
What does daptomycin target?
Inhibits DNA/RNA synthesis
What is the spectrum of daptomycin
G+ve only
What class is linezolid in?
It is an oxazolidinone.
What does linezolid target?
It binds the 30s subunit and inhibits protein synthesis.
What is the spectrum of linezolid?
Gram positives only
Includes MRSA, VRE, mycobacterium
What side effects can linezolid have?
Bone marrow suppression
Optic neuropathy
Peripheral neuropathy
What does fusilier acid target?
It targets protein synthesis.
It targets the G-factor and inhibits ribosomal translocation.
What is the spectrum of fusidic acid?
Staphylococci mostly
Never used alonE
IV, oral, topical
What are the side effects of fusidic acid?
Hepatotoxic
Thrombophlebitis
What does tetracycline target?
Binds the 30s subunit - inhibits ribosomal translocation
Inhibits protein synthesis.
What is the spectrum of tetracycline?
Broad spectrum
G+ve, g-ve and anaerobes
Give IV/oral
What are the side effects of tetracycline?
Causes teeth and bone discolouration in children
Don’t give to children or pregnant women
Can cause photo sensitivity
What is the target of Quinupristin/Dalfopristin (Synercid)??
It targets protein synthesis
50s subunit
What is the spectrum of synercid?
G+ve only (MRSA and VRE but not E. faecalis)
What side effects does synercid have?
Venous inflammation
Hepatotoxic
What does Rifampicin target?
Inhibits RNA polymerase
What is the spectrum of Rifampicin?
Broad spectrum
G+ve, G-ve, Anaerobes and Mycobacteria
DO NOT give alone
IV/Oral
What are the side effects of Rifampicin?
Hepatotoxic
Can cause Type I hypersensitivity reactions
Thrombocytopaenia
Induction of liver enzymes
What does Trimethoprim target?
Dihydrofolate reductase
-inhibits DNA synthesis
What is the spectrum of Trimethoprim
Broad spectrum
G+ve and G-ve
Doesn’t reach brain, skin or fat
Used for UT
What are the side effects of Trimethoprim?
Gastrointesinal upsets
Type I hypersensitivity
Bone marrow depression
can be teratogenic in the first trimester.
What does metronidazole target?
it is non-enzymatically reduced by reacting with reduced ferredoxin. Many of the reduced nitroso intermediates will form sulfinamides and thioether linkages with cysteine-bearing enzymes, thereby deactivating these critical enzymes.
What is the spectrum of metronidazole?
Anaerobes
Parasites
What are the side effects of metronidazole?
Nausea Reduced WCC Neurotoxic Rash Reacts with alcohol
What class of antibiotics is Astreonam in?
Monobactams
What is the spectrum of Astreonam?
G-ve mostly
What is the target of Astreonam?
Targets PbP3 at low concentrations
Low susceptibility to b-lactamases
Name four third generation cephalosporins
Cefotaxime
Ceftazidime
Cefixime
Ceftriaxone
Name a fourth generation cephalosporin
Cefipime
What is the spectrum of cephalosporins
Broad - more active against g-ve b-lactamases
Active against pseudomonas
Can cross the BBB
Risk of CDAD
Name 2 second generation cephalosporins
Cefuroxime
Cefoxitin
What spectrum is Tazocin?
Extended spectrum pseudomonas B-lactam
G+ve, G-ve, some anaerobes
Used to treat pneumonia
What is the spectrum of Flucloxacillin?
G+ve Staphylococci/Streptococci
stable to b-lactamases
What is the spectrum of ampicillin/amoxicillin?
Streptococci Neisseria Haemophilus E. Faecalis Some staphs Some coliforms Used for UTIs, Otitis Media, and in combination with flucloxacillin for cellulitis
What is the spectrum of benzylpenicillin?
Streptococci
Neisseria
some staphs - quite narrow spectrum
Synergistic with aminoglycosides
What class does Imipenem belong to?
Carbapenems
What is the spectrum of imipenem?
Very broad spectrum
Resistant to beta lactamases
Covers pseudomonas
NOT active against MRSA
What class does Teicoplanin belong to?
Glycopeptides
Cell wall active - bind terminal D-ala-D-ala residues
What is the spectrum of Teicoplanin?
Gram positives only - too large for G-ve
Used for MRSA/MRSE
What are the side effects of Teicoplanin?
Ototoxic
Nephrotoxic
Excreted renally
What class is vancomycin in?
Glycopeptides
what is the spectrum of vancomycin?
Gram positives only - too large for G-ve
IV only
Use for MRSA/MRSE
what are the side effects of vancomycin?
Ototoxic
Nephrotoxic
excreted renally
What class is Tobramycin in?
Aminoglycosides
What does Tobramycin target?
The 30s ribsosomal subunit (protein synthesis)
What is the spectrum of tobramycin
Staphylococci Coliforms Pseudomonas NOT streptococci Use for UTIs and septicaemia as poor tissue penetration
WHat side effects does tobramycin have?
Ototoxic
Nephrotoxic
Excreted renally
WHat class is gentamicin in?
Aminoglycosides
What does gentamicin target in the cell?
30s subunit of ribosome (protein synthesis)
What is the spectrum of gentamicin?
Coliforms,
Pseudomonas
Staphylococci (NOT streps)
IV or topical
show synergy with b-lactams for enterococci
Mainly used for sepsis and UTIs as poor penetration of tissues
What side effects does gentamicin have?
Nephrotoxic
Ototoxic
Excreted renally
