Abx in children Flashcards
what host factors should be taken into account when picking abx for kids
age, pregnancy, immune status
site of infection
renal/hepatic fxn
what are the elements of pharmacokinetics?
drughost
ADME absorption distribution metabolism excretion
what abx have 100% oral bioavailability
clinda
flagyll
fluoroguinolones
what abx distributions completely to the tissues (has NO blood level)
azithro
what are the elements of pharmacodynamics
effects
time course of activity
toxicity
what is the MIC
minimum inhibitory concentration
minimum amount of an abx necessary to inhibit the growth of an organism
what is the MBC
minimum bactericidal concentration
the minimum amount of an abx necessary to kill 99% of an organism
what is the attainable drug level
concentration of the drug in tissues (blood, uring, CSF) which will result when it is administered according to a standard dose
what does it mean to say an organism is susceptible to an abx
organism will be inhibited or killed by the average attainable drug level in the body
MIC
what does it mean to say an organism is resistant to an abx
organism will not be killed by average attainable drug level in the body
MIC>attainable drug level
what are the major parameters of efficacy of abx
time/MIC
peak/MIC
24 hour AUC/MIC
in what drugs do we look at peak/MIC
animoglycosides
daptomycin
in what drugs do we look at AUC/MIC (area under concentration and time curve for the abx)
fluoroquinoloes
macrolides
tetracycline
vancomycin
in what drugs do we look at time > MIC
beta lactams
what are the mechanisms by which drugs achieve resistance to abx
- diminished intracellular drug concentration–> either by increased efflux or by decreased membrane permability
- drug inactivation–> usually by enzymes possessed by organism
- target modification
- target bypass
which drugs are affected by increased efflux resistance
tetracyclin (tetA)
quinolones (norA)
which drugs are affected by decreased membrane permeability resistance
beta lactams (ompF, oprD)
quinoloes (ompF)
aminoglycosides (decreased energy)
which drugs are affected by drug inactivation resistance
beta lactams (lactamase)
aminoglycosides (modifying enzyme)
ampC–cephalosporinase in Klebsiella
which drugs are affected by target modification resistance
quinolones (gyrase)
rifampin (DNApol)
beta lactams (PBP)
macrolides (rRNA methylation)
streptomycin (rDNA genes)
macrolides (methylation)
which drugs are affected by target bypass resistance
glycopeptides
bactrim
trimethoprim resistance
what is induction verus selection with regard to resistance
- selection is a problem on a population level over time–> statistically 1/1x10e6 is resistant to a drug
- induction is a problem for the individual during therapy–> AmpC cephalosporinase–> ESSCAPPPEM
what are the ESSCAPPPEM organisms and why do we care
care because have AmpC cephalosporinace activity
enterobacter
stenostrophomonas
serratia
cirtobacter
acinetobacter
pseudomonas
providencia
proteus
morganella
what are the two reasons/theories behind dual therapy of abx
either synergistic or combination
synergistic–> two drugs have an effect greater than the sum of their treatments–> increases rate and killing for example
–> i.e amp/gent for enterococcus
combination–> invovles using drugs with different MOAs to decrease the chance of resistance to break through
what are the cell wall synthesis inhibitor abxs
- beta lactams–> penicillins, cephalosporins, carbapenems
(beta lactamase inhibs in organisms can mess with these) - glycopeptides–>vanco
what are the protein synthesis inhibitor abxs
- aminoglycosides–> gentamicin, tobramycin, amikacin, streptomycin
- macrolides–> erythromycin, clarithromycin, azithromycin
- other–> clinda, linezolid, tetracyclines (doxy)
what are the RNA or DNA synthesis inhibitor abxs
- RNA transcription inhibitor –> rifampin
- DNA synthesis inhibitors–> fluoroquinolones (cipro and levofloxacin)
- nucleotide synthesis inhibitors–> TMP-SXT
how does metronidazole work
toxic free radical production
what are bacteriostatic abxs
inhibit bacterial cell growth
need INTACT IMMUNE SYSTEM to fight infection
what are bacteriocidal abxs
kill bacteria directly
do not rely on immune system of patient
(therefore okay in immunocompromised)