5 - drug selection
define empirical antimicrobial drug therapy
initiation of antimicrobial drug therapy before identification of the infecting microorganism and its antibiotic susceptibility
how do you decide which patients to treat with an antimicrobial drug? what conditions must be present to justify treatment with an antimicrobial drug
is there a bacterial infection
does it require treatment with an antibacterial drug
what is the most likely pathogen
can we identify the pathogen
when should microbial culture and susceptibility be performed
retreatment/reoccurance occurs
treatment failure
what is the simplest way to accurately determine the best way to collect, store, and ship samples for bacterial culture at a diagnostic laboratory
call them
what is required in order to achieve success with antimicrobial drug therapy
the pathogen is susceptible to the drug
sufficient drug concentration can be achieved at the site of the infeciton
the patient can tolerate the drug at the dosage used.
describe the step-wise process of antimicrobial drug selection
determine if the case requires antimicrobial therapy
determine what the most likely pathogen is
determine what the pathogen is most likely to be susceptible to
determine if the drug can achieve sufficient concentration at the affected area
what is the clinical implication of a drug being characterized as bacteriostatic or bactericidal
myth: bactericidal is more effective
fact: neither is more effective than the other. use whichever one will achieve treatment
when is IV administration of an antibacterial drug indicated
initial dose is needed to quickly achieve effective concentration → loading dose
explain factors to be considered when prescribing or dispensing antibacterial drugs
is the pathogen susceptible
will the drug achieve effective concentration at the affected tissue