Antibiotics Flashcards
Benzyl penicillin (penicillin G)
Original naturally occurring penicillin
Beta lactam - disrupts peptidoglycan synthesis (PBPs)
Largely acts against Gram(+) bacteria
Many Gram(-) bacteria are resistant due to presence of impermeable outer layer
Best choice for IV treatment of pneumococcal, meningococcal and S. pyogenes infection
Amoxicillin and ampicillin
Beta lactam penicillin
Better oral absorption
Better Gram(-) activity
Covers streptococci, enterococci and some coliforms
Co-amoxiclav
Beta lactam penicillin
Amoxicillin + clvulanic acid = beta lactamse inhibitor
Extended spectrum
Covers beta lactamase producing coliforms
Fluocloxacillin
Beta lactam penicillin
First choice of treatment in staphylococcal infection
Piperacillin
Beta lactam penicillin Extended gram negative coverage Anti-anaerobic activity Active against E. faecalis Only one active against Pseudomonas spp Used in combination with tazobactam = beta lactamse inh
Imipenem, meropenem
Carbapenems = beta lactam penicillin subgroup
Widest spectrum of all
Cover anaerobes
Active against most bacteria
Cephalosporins
Divided into generations based on order of appearance
Activity against Gram(-) increases with generations
Activity against Gram(+) decreases with generations
Encourage C. difficile infection
Cephradine
First generation cephalosporin
Cefuroxime
Second generation cephalosporin
Ceftriaxone
Third generation cephalosporin
Ceftazidine
Third generation cephalosporin
Only one with activity against Pseudomonas spp
Glycopeptides
Inhibit cell wall synthesis
Act at a stage prior to beta lactams
Unable to penetrate Gram(-) cell walls
Only active against Gram(+) bacteria
Active against both aerobes and anaerobes
Parenteral use only (not absorbed from GI tract)
Vancomycin
Glycopeptide
Ototoxic, nephrotoxic, skin rash
Requires slow infusion and monitoring
Teicoplanin
Glycopeptide
Less toxic
Single daily dosing
Aminoglycosides
Inhibitors of protein synthesis Primarily used in Gram(-) infections (coliforms, pseudomonas) Active against staphylococci Inactive against streptococci Parenteral use only
Gentamicin
Aminoglycoside
Ototoxic, nephrotoxic
Requires careful dosing and monitoring
Macrolides
Inhibitors of protein synthesis
Newer ones have lower MICs
Mainly active against Gram(+) bacteria
Good alternatives to penicillins in patients with penicillin hypersensitivity
Effective against organisms causing atypical pneumonias e.g. C. psittacci, C. burnetti and M. pneumoniae
First choice therapy in Legionella pneumophila
S. aureus, S. pyogenes and S. pneumonia are resistant
Clarithromycin
Macrolide
Erythromycin
Macrolide
Azithromycin
Newer macrolide
Single dose treatment of Chlamydia
Tetracyclins
Inhibitors of protein synthesis
Few limited applications in genital tract infections with chlamidya and respiratory tract infections with C. psittacci and M. pneumoniae
Not indicated for pregnant women
Not indicated in children under 12 - deposited in teeth and bone
Oxazolidinones
Inhibitors of protein synthesis
Linezolid
Oxazolidinone
Active against MRSA
Can be given orally
Can cause BM suppression
Cyclic lipopetides
Inhibitors of protein synthesis
Daptomycin
Cyclic lipopetides
Active against Gram(+) bacteria only
Active against MRSA
Trimethoprim
Inhibitor of nucleic acid synthesis (purine)
Alone used in UTIs
Co-trimoxazole
Inhibitor of nucleic acid synthesis (purine)
Combination of trimethoprim and sulphamethoxazole
Treatment of chest infections
Less likely to cause C. difficile infection
Fluoroquinolones
Inhibitors of DNA synthesis
Both oral and parenteral use
Mostly effective against Gram(-) bacteria
Cannot be used in children due to interference with cartilage growth
Ciprofloxacin
Newer generation quionolone
Only oral treatment for Pseudomonas spp
Activity against staphylococci acceptable
Activity against steptococci poor
Levofloxacin
Newer quinolone
Active against pneumococci
Nalidixic acid
First generation quinolone
Urinary antiseptic - only used in UTIs
Only active against gram negative aerobe coliforms
Metronidazole
Antibiotic of choice for anaerobic infections
Fusidic acid
Only indicated against staphylococci
Usually in combination with flucloxacillin
DIffuses well into bone and tissue - staphylococcal osteomyelitis and pneumonia
Clindamycin
Lincosamide antibiotic Active against Gram(+) bacteria Active against anaerobes Good tissue penetration Oral administration Causes pseudo-membranous colitis
Nitrofurantoin
Urinary antiseptic used in UTIs
