Flashcards in Penicillins Lecture 13 Deck (14):
Structure and chemistry
House with garage
betalactamase inhibitor irreversibly binds to a beta lactamase
inhibit bacterial cell wall synthesis by blocking crosslinking of adjacent peptidoglycan strands with subsequent lysis.
penicillin binding proteins (PBPs) are target of B lactam antibiotics and include transpeptidases, transglycolases, and D alanine carboxykinase.
peptido glycan transpeptidase is on PBP that is inhibiited
betalactamse production: staph, H. Flu
failure of antibiotic to penetrate to PBP target: gram negative organisms only (porin channel penetration)
low affinity binding of antibiotic to PBPs: pneumococcus, MRSA, enterococcus
Some are acid stable and others not.
peak levels 1-2 hours after ingestion
food delays and decreases absorption. Absorption not deceased with Pen V, Amoxicillin, and carbenicillin
insoluble in lipid; therefore unless inflammation is present there is poor distirbution to brain, CSF, and prostate
metabolized to some degree based on agent
renal excretion is the most important route of elimination: adjustment for renal insufficiency is a must. Infants excrete penicillins at a slower rate due to immature transport systems
biliary excretion occurs with ampicillin, nafcillin, and the antipseduomonal penicillins
hypersensitivity reactions: most common adverse effect. All penicillins have equal potential for inducing allergic reaction. Hypersensitivity to one means probable hypersensitivity to all penicillins. Hypersensitivity may not occur on reexposure or may occur without previous reaction. Immediate reaction (anaphylaxis)- IgE mediated. Delayed reaction (rash)- IgM or IgG mediated. Maculopapular rash is most common
hematologic (eosinophilia, thrombocytopenia, neutropenia), interstitial nephritis, pseudomembranous colitis
Spectrum of activity: gram positive organisms (streptococcus and some entercoccus)
staph. produce B lactamase: 995 resistant.
Warning: strep. pneumonia resistance prevalent in some areas.
amino group allows for penetration into gram negative cell wall
SoA: streptococcus, enterococcus, haemophilus (non b lactamase producing), proteus mirabilis (watch sensitivity), e coli (watch sensitivity, esp if GI is the source of E coli), Klebsiella (watch sensitivity
AE: diarrhea (take with food amoxicillin absorption not impaired). Ampicillin > amoxicillin
Penicillanse resistant Penicillins
cover streptococcus and beta lactamase positive staph.
IV: methacillin, oxacillin, nafcillin (hepatic elimin)
PO: cloxacillin, dicloxacillin
increased permeability to cell wall
SOA: streptococcus, proteus, e. coli, klebsiella, SPACE. First group in PCN. Enterbacter spp,
carbenicillin: indanyl salt: stable oral form. High urine concentrations. Body normally cannot tolerate high dosages necessary for concentrations to treat systemic infections
ticarcillin: 2-4 x more active than carbenicillin against pseudomonas
NA load = 5.2 MEQ/GM
adverse effects: hypersensitivity. carboxy group can cause platelet dysfunction (dose dependent). Na overload (hypernatremia, severe CHF, and renal failure)
piperacillin (low Na Load)
SOA: streptoccus, enterococcus (more potent than carboxypenicillins), proteus, e coli, klebsiella, space bugs