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Flashcards in Penicillins Lecture 13 Deck (14):
1

Structure and chemistry

House with garage

betalactam ring

betalactamase inhibitor irreversibly binds to a beta lactamase

2

MoA

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

bactericidal

3

MoR

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

4

Absorption

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

5

distribution

well distributed

insoluble in lipid; therefore unless inflammation is present there is poor distirbution to brain, CSF, and prostate

6

metabolism

metabolized to some degree based on agent

7

excretion

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

8

AE

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

9

penicillin G

Spectrum of activity: gram positive organisms (streptococcus and some entercoccus)

staph. produce B lactamase: 995 resistant.

Warning: strep. pneumonia resistance prevalent in some areas.

10

aminopeniciilins

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

11

Penicillanse resistant Penicillins

antistaphylococcal penicillins

cover streptococcus and beta lactamase positive staph.

IV: methacillin, oxacillin, nafcillin (hepatic elimin)

PO: cloxacillin, dicloxacillin

12

carboxypenicillins

Carbenicillin/Ticarcillin

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)

13

ureidopenicillins

piperacillin (low Na Load)

SOA: streptoccus, enterococcus (more potent than carboxypenicillins), proteus, e coli, klebsiella, space bugs

14

Betalactamase inhibitor/penicillin combination

augmentin (amox and clavulanic acid) PO

unasyn (ampicillin and sulbactam) IV

timentin (tacarcillin and clavulanic acid) IV

sozyn (piperacillin and tazobactam) IV