Drugs Flashcards
Concentration dependent killing
Vs.
Time dependent killing
Kill based on peak concentration (optimal above 10x MIC)
Kill based on amount of time concentration above MIC
Inhibitors of cell wall synthesis
Penicillins Carbapenems Cephalosporins Aztreonam Vancomycin Bacitracin Cycloserine
Inhibitors of protein synthesis/structure
Aminoglycosides Chloramphenicol Erythromycin, clindamycin, lincomycin Tetracyclines Streptogramins/linezolid
Interference with cell membrane function
Polymixin B, colistin
Azole and polyene (antifungals)
Interference with DNA/RNA synthesis
Rifampin
Fluoroquinones
Inhibitors of metabolism
Isoniazid, ethambutol
Sulfonamides, trimethoprim
Guidelines for selecting and using antimicrobial agents
Confirm presence of infection
Determine site of infection
Determine causative organism(s)
Select drug
Follow response and alter therapy as necessary
Select a drug based on
Sensitivity of the microorganism
Physiochemical properties
Toxicities of the drug
Patient characteristics
Reasons to start empiric abx coverage
Site of infection difficult to culture
Serious or life threatening infections
Notes: culture site before starting
Gram stains - quick and very informative for selecting
Penicillins/cephalosporins
Mechanism of resistance
Beta-lactamases
PBP changes
Porin channel changes
Aminoglycosides
Mechanism of resistance
Enzyme inactivating
Macrolides
Mechanism of resistance
Methyltransferases that alter drug binding sites on 50s ribosomal subunit
Tetracyclines
mechanism of resistance
Transport systems that pump drugs out of the cell
Sulfonamides
Mechanism of resistance
Increased PABA formation
Target enzyme sensitivity
Fluoroquinones
Mechanism of resistance
Target enzyme changes
Drug efflux
Gram positive class
Staphylococcus
Streptococcus
Enterococcus
Gram negative
Piddly
Haemophilus Morexella Morganella Shigella Salmonella (Providencia, neisseria)
Gram negative
Fence
Proteus
Eschericia coli
Klebsiella
Gram negative
SPACE
Serratia Pseudomonas Acinetobacter Citrobactor Enterobactrer
Atypical class
Chlamydia
Mycoplasma
Legionella
Anaerobes class
Peptostreptococcus
Bacteroides
Clostridium
Post Antibiotic Effect (PAE)
Persistent effect on bacterial growth following brief exposure of organisms to a drug
Aminoglycosides & fluoroquinones
Penicillin G
Binds PBP & blocks crosslink peptidoglycan
Strep, some enterococcus
Acid labile
Rheumatic fever prophylaxis
Penicillin VK
Binds PBP
Strep, some enterococcus
Acid stabile
Absorption not slowed by food
Anti penicillinase penicillin (anti staph)
Methicillin, nafcillin, oxacillin (IV drugs)
cloxacillin, dicloxacillin (PO drugs)
Nafcillin - hepatic elimination
Strep and beta lactamase staph
Ampicillin
Bind PBP
Strep, ENTEROCOCCUS, and PEK gram neg
Diarrhea is major side effect
Amoxicillin
Bind PBP
Strep, enterococcus, PEK gram neg
Absorb not slowed by food
Diarrhea less so than amp
Carbenicillin
Bind PBP
Strep, PEK and SPACE gram neg (pseudomonas requires high concentrations)
Absorption not delayed by food
High urine but low systemic concentration
Ticarcillin
Bind PBP
Strep, PEK and SPACE gram neg (pseudomonas req. high concentration)
High sodium load!! (CHF, renal fail, hypernat.)
Pipercillin
Bind PBP
Strep, enterococcus, PEK and SPACE gram neg
Sodium load but much lower than ticarcillin
Adding beta lactamase inhibitor to penicillin
Augmentin- amox/clavulanic acid
Unasyn- amp/sulbactam
Zosyn- pipercillin/ tazobactam
Adds staph and anaerobes