Antimicrobials part 1 Flashcards Preview

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Flashcards in Antimicrobials part 1 Deck (39):
1

Penicillin V indication

Less active against gram -ve than PCN G

Gram +ve (except staph b/c beta lactamase)
Most anaerobes

**DOC for strep throat**

2

Penicillin V PK/PD

Acid stable
*Oral* version of PCN G

3

Ticarcillin, Carbenicillin, Piperacillin indication

TCP-takes care of pseudomonas
DOC for P. aeruginosa infections**

Effective agianst many *gram -ve* bacilli (better than other PCN's)

Combine with a beta-Lactamase inhibitor**

4

Ticarcillin, Carbenicillin, Piperacillin PK/PD

useful in moderate to severe infections

5

Penicillin G (Benzathine, procaine) indication

*Gram +ve*
Except staph -> beta lactamase **
Gram -ve cocci (Neisseria)
Most anaerobes

**DOC for syphilis (benzathine)**
Strep (preventing rheumatic fever)
Pneumococci

6

Penicillin G (benzathine, procaine) PK/PD

Susceptible to beta lactamases

Procaine -> IM increasing resistances so decreased use; not IV due to toxicity

Benzathine -> IM, half life 3-4 weeks; prolongs life of penicillin G

7

Amoxicillin, Ampicillin indication

*Extended spectrum* -> some gram -ve activity
Susceptible to beta lactamase -> adminitser with beta lactamase inhibitor

***URT's (H. flu & S. pneumo); UTI's (E. coli), P. mirabilis, Salmonella, Shigella
"HELPSS kill enterococci"

Amoxicillin -> endocarditis prophylaxis during dental or respiratory tract procedures **

Ampicillin -> used in combination with aminoglycoside to treat Listeria and enterococci

8

Amoxicillin, Ampicillin PK/PD

*Amoxicillin -> highest oral bioavailability*

******Safe for children and pregnancy********

**Ampicillin rash**

9

Nafcillin adverse

Neutropenia

10

Oxacillin adverse

Hepatitis

11

Ticarcillin adverse

inhibits platelet function therefore increased bleeding time

12

Methicillin, Nafcillin, Oxacillin, Dicloxacillin indication

***Anti staphylococcal***
*Beta lactamase resistance*
Methicillin never used clinically (Causes *AIN*)
Inactive against MRSA/ORSA

**DOC for staph endocarditis without a prosthetic valve**

13

Nafcillin PK/PD

Has erratic oral absorption and is excreted in the bile

14

Beta lactamase inhibitors

Clavulanic acid
Sulbactam
Tazobactam

15

Calvulanic acid, Sulbactam, Tazobactam description

aka: penicillinase or cephalosporinase

Contain a beta lactam ring, but do not have significant antibacterial activity
Available only in fixed combinations with specific PCN's

**Bind and inhibit most beta lactamases**

16

Penicillin mechanism

Bactericidal -> bind to PBP's inhibiting the last step in peptidoglycan synthesis

PCN activates *autolysin* - bacterial enzymes which mediates cell lysis

Autolysin + lack of cell wall synthesis= death

Oral absorption impaired by food
Distribution: do not achieve sufficient levels in *prostate and eye*
CSF penetration is poor except in meningitis
Nafcillin, ampicillin, and piperacillin -> high levels in bile

17

Penicillin excretion

Primarily excreted in kidney except for
*Nafcillin -> bile (useful when patients have renal insufficiency**)
*Oxacillin/dicloxacillin - renal and biliary excretion*

18

Penicillin description

Widely effective with little toxicity
Overuse -> increase levels of resistance (due to PBP mutations)

All have beta lactam ring

PCN + aminoglycoside (gram +ve and -ve)

19

Penicillin synergistic effect

PCN facilitates movement of AG through the cell wall
Formas an inactive complex if placed in the same IV solution

DOC for Empiric treatment of *infective endocarditis* ... PCN G + gentamicin (nowadays a lot of MD's use vancomycin instead of PCN)

20

Penicillin Hypersensitivity

Major Ag determinant -> penicilloic acid
Anything from a rash to anaphylaxis
Cross allergic reactivity between beta lactam ABx can occur (ex. cephalosporins)

21

Penicillin AE

Hypersensitivity
**Interstitial nephritis -> esp. methicillin** -> oliguria, fever, rash, + EOS in urine

GI disturbance
*Pseudomembranous colitis (esp ampicillin) or vaginal candida

*Maculopapular rash* when ampicillin or amoxicillin is given for a viral infection (not a hypersensitivity reaction)

Neurotoxicity in epileptics
Ticarcillin: inhibits platelet function, increase bleeding time
Nafcillin -> neutropenia
Oxacillin -> hepatitis

22

Penicillin mechanisms of resistance

Inactivation by betalactamase
Modified PBP's
Impaired penetration
Increased efflux

23

Penicillin time dependent killing

increasing concentration only adds to risk for AE; length of time spent over MIC is the most important

24

Penicillin spectrum

Spectrum is based on the ability to 'reach" the PBP's -> based on size, charge and hydrophobicity

Gram +ve -> cell wall is easily accessed
Gram -ve -> porins permit entry

25

Penicillin desensitization

used in pregnant women with penicillin allergy (because nothing else can be used to treat them*

26

PBPs

PBPs are penicillin binding proteins (bacterial enzymes) involved in peptidoglycan synthesis

Penicillins require the microbe to be actively proliferating (cell wall synthesis must be occurring)

27

Beta lactam antibiotics

Penicillins
Cephalosporins
Carbapenems
Monobactams

All target PBPs

28

Monobactam drug

Aztreonam

29

Aztreonam indication

**Only for aerobic gram -ve rods**
Including pseudomonas, UTI's, sepsis

30

Aztreonam PK/PD

IV or IM - parenteral only
*Inhalation (Cystic fibrosis patients)*
Penetrates CSF when inflamed

31

Aztreonam mechanism

Binds PBP's -> inhibits cell wall synthesis

Eliminated in urine (monitor renal function)

32

Aztreonam AE

Little cross-reactivity -> can be used in patients with PCN anaphylaxis

Relatively non toxic
Rarely causes increase aminotransferase, skin rash, GI upset, vertigo, HA

33

Aztreonam Funcat

Resists hydrolysis by most beta lactamases

34

Carbapenem drugs

Imipenem
Meropenem

35

Carbapenem indication

Synthetic beta lactam antibiotics

**DOC for Enterobacter infection and extended spectrum beta lactamase producing gram -ve's**

36

Carbapenem PK/PD

*Very broad spectrum* but not effective against MRSA

IV

37

Carbapenem Mechanism

*Resist hydrolysis by most beta lactamases*

Resistance is becoming a huge problem -> restrict use

38

Carbapenem AE

GI distress
*Imipenem ->seizures*

*Partial cross reactivity with PCN*

39

Carbapenem fun facts

Imipenem forms a *nephrotoxic* metabolite -> combine with *Cilastatin* to *reduce toxicity and increase availability*