Antimicrobials: PCNs/BLI Flashcards
Penicillins are what type of antibiotics?
cell wall active
Penicillins are what type of antibiotics?
cell wall active, beta lactam.
Penicillin MoA
Disrupts bacterial cell wall formation by inhibiting certain enzymes which create cross-linking, resulting in cell lysis and cell death.
Dose adjustments for PCNs (2)
- dose adjust for CrCl < 50 ml/min
- may need hepatic adjustment
what do dose adjustments for PCN look like?
More often extending the interval between doses rather than decreasing the dose.
spectrum of activity for PCNs
mostly gram positive
some have gram negative activity
5 classes of penicillins
- natural
- aminos
- pennicillinase resistant (aka anti staph)
- ureidos (aka anti pseudomonal)
- beta lactamase inhibitors
adverse events: PCNs (4)
hypersensitivity
neutropenia
interstitial nephritis
CNS toxicity (seizures)
caution of PCN use in the longterm
neutropenia
interstitial nephritis in PCN use
Symptoms and action
inc BUN
inc creatinine
inc in eiosiniphils
potential fever
will have to stop the drug.
absorption of PCNs is hindered by
susceptible to first pass effect
peak concentration of PCNs
1-2 hours
half life of PCNs
short
distribution of PCN
widely distributed to tissues/fluids
metabolism of PCNs
none to minimal hepatic metabolism
elimination of PCN (2)
kidneys
some biliary
natural PCNs are indicated for what organisms? (4)
- streptococcal
- enterococcus
- t. pallidum
-some anaerobes like peptococcous / peptostreptococcus
natural penicillin drugs (4)
PCN G
PCN V
procaine PCN
benzathine PCN
distribution sites of PCNs (6)
lungs ascites synovium pericardium ascitic fluid soft tissues
drug of choice for Treponema pallidum (ie: syphilis)
natural PCN
natural PCN dose adjustment
for CrCl <50
Natural PCN is the drug of choice for (2)
syphilis
Strep
aminopenicillins MoA/activity
Same as natural PCN + extended gram negative spectrum.
Aminopenicillins do not do well with treating
Staph
Aminopenicillins are more active against ______ than other PCNs.
Enterococcus
drug examples of aminopenicillin (2)
amoxicillin
ampicillin
important point about aminopenicillins
they are not very beta lactamase stable and frequently are targeted by beta lactamase released by bacteria,
distribution of aminopenicillins (4)
renal tissue
septic joints
ascites
CSF (if inflamed meninges)
aminopenicillin is the drug of choice for?
for sensitive enterococcal infections.
when circumstance may aminopenicillin be warranted?
UTIs while pregnant.
penicillinase resistant PCNs (anti staph PCNs) are clinically effective for
staphylococcus aureus ***
streptococcal
peptrostreptococcal
Penicillinase resistant PCN (anti staph) drug examples (3)
oxacillin
nafcillin
dicloxacillin
Penicillinase resistant PCNS (anti staph) gram activity
gram positive only. no gram neg activity.
Penicillinase resistant PCNs (anti staph) distribution
bone joint cardiac tissue (endocarditis)
Penicillinase resistant PCNs (anti staph) are the drug of choice for
MSSA
methicillin sensitive S aureus infections
Why are Penicillinase resistant PCNs (anti staph) the drug of choice against MSSA?
Their structure prevents the B-lactamase made by S. aureus from attacking the B-lactam nucleus.
Penicillinase resistant PCNs (anti staph) dosing and half life
very short half life
give q4 hrs
Penicillinase resistant PCNs (anti staph) dosage adjustment
for severe hepatic impairment
drawback of nafcillin, a Penicillinase resistant PCNs (anti staph)
large sodium content when given IV
elimination of Penicillinase resistant PCNs (anti staph)
hepatic, not renal
Penicillinase resistant PCNs (anti staph) in the renal patient
safe b/c this drug is eliminated by the liver
Ureidopenicillins (Anti Pseudomonal PCNs) product
piperacillin
Ureidopenicillins (Anti Pseudomonal PCNs) known as Piperacillin is indicated in
gram negatives:
pseudomonas
bacteroides
Ureidopenicillins (Anti Pseudomonal PCNs) known as Piperacillin may also be used for
some enterococcal
Ureidopenicillins (Anti Pseudomonal PCNs) known as Piperacillin works against aerobes or anaerobes?
Mainly aerobes
slight coverage of anaerobes
Ureidopenicillins (Anti Pseudomonal PCNs) known as Piperacillin and staphylococcus
no efficacy
beta lactamase stability of Ureidopenicillins (Anti Pseudomonal PCNs) known as Piperacillin
piperacillin not very beta lactamase stable.
piperacillin is always given with what and why?
a BLI (beta lactamase inhibitor)
Ureidopenicillins (Anti Pseudomonal PCNs) known as Piperacillin distribution
pleural
ascities
wounds
dose adjustment for Ureidopenicillins (Anti Pseudomonal PCNs) known as Piperacillin
dose adjust for CrCl <50mL/min
Beta-Lactam/Beta Lactamase Inhibitors active against
H influenza
M Catarrhalis
N gonorrhoeae
B fragilis
Beta-Lactam/Beta Lactamase Inhibitors gram activity
gram negative (including anaerobes) and gram positive
Beta-Lactam/Beta Lactamase Inhibitors are very useful in what two scenarios
“mixed” infections
or broad empiric coverage as a single agent
Beta-Lactam/Beta Lactamase Inhibitors - how do they work?
Act as a decoy against the beta lactamase being produced by organism. BLIs block the attack on the B lactam nucleus by absorbing the attack themselves, thus allowing binding to transpeptidase enzymes and disruption of cell wall formation. They have no antimicrobial activity.
Beta-Lactam/Beta Lactamase Inhibitors examples
- Ampicillin/Sulbactam
- Amoxicillin/Clavulnic Acid
- Pipercillin/Tazobactam
Beta-Lactam/Beta Lactamase Inhibitors distribution
high
Beta-Lactam/Beta Lactamase Inhibitors dose adjustment
CrCl < 50 mL/min
Piperacillin/Tazobactam is the only combo indicated for
psuedomonas
Amoxicillin/Clavulanic Acid (Augmentin) main side effect
diarrhea
General monitoring for PCNs
C&S
CBC c diff
LFTs
RFTs
Pregnancy and lactation considerations for PCNs (3)
Category B
Crosses Placenta
Excreted in milk
What population is most susceptible to the side effects of PCNs?
newborns and geriatric
Which natural PCN requires hepatic dose adjustment?
PCN G
In general, PCNs are great against
staph
strep
& some PCNs have broader activity
likely to see interstitial nephritis in what combo?
PCN with vanco
