Antimicrobials part 1 Flashcards Preview

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Flashcards in Antimicrobials part 1 Deck (39)
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1
Q

Penicillin V indication

A

Less active against gram -ve than PCN G

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

DOC for strep throat

2
Q

Penicillin V PK/PD

A

Acid stable

Oral version of PCN G

3
Q

Ticarcillin, Carbenicillin, Piperacillin indication

A

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
Q

Ticarcillin, Carbenicillin, Piperacillin PK/PD

A

useful in moderate to severe infections

5
Q

Penicillin G (Benzathine, procaine) indication

A

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

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

6
Q

Penicillin G (benzathine, procaine) PK/PD

A

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
Q

Amoxicillin, Ampicillin indication

A

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
Q

Amoxicillin, Ampicillin PK/PD

A

Amoxicillin -> highest oral bioavailability

**Safe for children and pregnancy**

Ampicillin rash

9
Q

Nafcillin adverse

A

Neutropenia

10
Q

Oxacillin adverse

A

Hepatitis

11
Q

Ticarcillin adverse

A

inhibits platelet function therefore increased bleeding time

12
Q

Methicillin, Nafcillin, Oxacillin, Dicloxacillin indication

A

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

DOC for staph endocarditis without a prosthetic valve

13
Q

Nafcillin PK/PD

A

Has erratic oral absorption and is excreted in the bile

14
Q

Beta lactamase inhibitors

A

Clavulanic acid
Sulbactam
Tazobactam

15
Q

Calvulanic acid, Sulbactam, Tazobactam description

A

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
Q

Penicillin mechanism

A

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
Q

Penicillin excretion

A

Primarily excreted in kidney except for

  • Nafcillin -> bile (useful when patients have renal insufficiency**)
  • Oxacillin/dicloxacillin - renal and biliary excretion*
18
Q

Penicillin description

A

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
Q

Penicillin synergistic effect

A

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
Q

Penicillin Hypersensitivity

A

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

21
Q

Penicillin AE

A

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
Q

Penicillin mechanisms of resistance

A

Inactivation by betalactamase
Modified PBP’s
Impaired penetration
Increased efflux

23
Q

Penicillin time dependent killing

A

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

24
Q

Penicillin spectrum

A

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
Q

Penicillin desensitization

A

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

26
Q

PBPs

A

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
Q

Beta lactam antibiotics

A

Penicillins
Cephalosporins
Carbapenems
Monobactams

All target PBPs

28
Q

Monobactam drug

A

Aztreonam

29
Q

Aztreonam indication

A

Only for aerobic gram -ve rods

Including pseudomonas, UTI’s, sepsis

30
Q

Aztreonam PK/PD

A

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

31
Q

Aztreonam mechanism

A

Binds PBP’s -> inhibits cell wall synthesis

Eliminated in urine (monitor renal function)

32
Q

Aztreonam AE

A

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
Q

Aztreonam Funcat

A

Resists hydrolysis by most beta lactamases

34
Q

Carbapenem drugs

A

Imipenem

Meropenem

35
Q

Carbapenem indication

A

Synthetic beta lactam antibiotics

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

36
Q

Carbapenem PK/PD

A

Very broad spectrum but not effective against MRSA

IV

37
Q

Carbapenem Mechanism

A

Resist hydrolysis by most beta lactamases

Resistance is becoming a huge problem -> restrict use

38
Q

Carbapenem AE

A

GI distress
Imipenem ->seizures

Partial cross reactivity with PCN

39
Q

Carbapenem fun facts

A

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