Antimicrobial Pharmacology Flashcards
antibiotic
substances produced by microorganisms intended to suppress other microorganisms
naturally produced
antimicrobial
all agents that kill or inhibit growth of all types of microorganisms
- antibacterial/fungal/viral
naturally or therapeutically produced
therapeutic triad
host, drug, organism
three considerations for achieving sufficient concentration of appropriate antimicrobial at the target site to eradicate the organism and minimize adverse effects and resistance development
goal of antimicrobial treatment
concentration of antibacterial agent at site of infection must inhibit pathogen and remain below level that may be toxic to host
components of appropriate antimicrobial use
- presence of bacteria
- select appropriate antimicrobial
- dose to achieve therapeutic concentrations
- use at a time when likely to prevent/treat disease
- route of administration
- duration of therapy
- modify therapy as needed
susceptibility testing
establishes drug sensitivity and determines effective antibiotic concentration
minimum inhibitory concentration (MIC)
lowest concentration that prevents visible growth
indicates concentration required to target the organism at the target site
minimum bactericidal concentration (MBC)
lowest concentration of antimicrobial that will kill an organism
bacteriostatic
ability to inhibit growth of an organism
MBC > 4xMIC
relies on hosts own immune system to clear the infection completely - only use in immunocompetent animals
bactericidal
ability to kill an organism
MBC < 4xMIC
does not rely on hosts own immune system
broad spectrum
effective against a wide range of microorganisms
more likely to kill natural microbiome
narrow spectrum
effective against a limited range of bacteria
what are the targets of antimicrobials
things/processes that are necessary for cell survival
PK/PD relationship
host factors vs drug factors
determines drug efficacy
PK
drug concentration that the organism is exposed to throughout dosing interval
depends on Cmax and AUC
PD
response of infecting organism to the drug
depends on MIC
absorption
drug administration into the body
- IV
- topical
- oral
when are IV antimicrobials used
critically ill patients or hard to reach organs
when are topical antimicrobials used
drugs that are too toxic for systemic administration
when are oral antimicrobials used
long term use
non hospitalized patients
target site is GIT
are slow use formulations appropriate for antimicrobials
no - often won’t reach MIC
distribution
getting the drug to the site of infection
protected sites
areas that are difficult to reach with drugs
- organs w/ continuous capillaries
- CNS, eyes, prostate, lungs, intracellular
more lipophilic drugs are more likely to reach
what are some local factors that affect pharmacokinetics
- pus, necrotic, infected tissue, cell debris
- cell material
- surgical implants
- acidic envionments
