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Pharma 2nd semester > C. 8. Penicillins > Flashcards

C. 8. Penicillins Flashcards

1
Q

what are Beta-lactam antibiotics?

A

Ab that inhibits cell wall synthesis

they all have β-lactam ring

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2
Q

what does a peptidoglycan layer consist of?

A

a chain of cross-linked disaccharide residues of N-acetylglucosamine and N-acetylmuramic acid

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3
Q

what are the targets of beta-lactam Ab?

A

Penicillin-binding-proteins (PBP’s)

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4
Q

where are PBP’s located?

A

on the cell wall of bacteria (peptidoglycan layer)

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5
Q

what is the effect of β-lactam Ab?

A

when exposed to bacteria, they bind to specific PBP’s on the bacterial cell wall and inhibit the assembly of the peptidoglycan chains–> this activates autolysin enzymes that degrade the cell wall–> bactericidal effect

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6
Q

what is the major mechanism of bacterial resistance?

A

β-lactamases (penicillinases)

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7
Q

what do β-lactamases do?

A

enzymatic hydrolysis of the β-lactam ring resulting in loss of antibacterial activity

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8
Q

what is the clinical presentation of interstitial nephritis?

A 
fever
oliguria
BUN/Cr ratio ↑
Eosinophils in urine
WBC casts -->'sterile pyuria'
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9
Q

commonly used combination preparations

A

Amoxicillin+ Clavulanic avid (β- lactamase inhibitor)
Ampicillin/Sulbactam
Piperacillin/Tazobactam

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10
Q

what ↑ penicillin in serum concentration?

A

probenecid

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11
Q

can penicillin cross the BBB?

A

only when the meninges are inflamed

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12
Q

penicillin synergistic effect with…

A

aminoglycosides

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13
Q

what happens when we combine penicillin with β- lactamase inhibitors (clavulanic acid, sulbactam, tazobactam)?

A

enhanced activity

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14
Q

what is the T1/2 of penicillin?

A

30-60 min

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15
Q

what are the mechanisms of intrinsic resistance of penicillin?

A
  1. no cell wall (mycoplasma, ureaplasma)
  2. intracellular parasites (chlamydia, rickettsia)
  3. slowly-growing bacteria (mycoplasma)
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16
Q

what are the mechanisms of acquired resistance of penicillin?

A
  1. penicillinases–> break lactam ring structure (staphylococci)
  2. structure change in PBP’s (MRSA, PRSP)
  3. change in porin structure (pseudomonas)
17
Q

list the narrow spectrum, β- lactamase sensitive penicillins

A 
Penicillin G (iv) and Penicillin V (ORAL) -natural 
Benzathine Peniciliin G (IM)
18
Q

what is the indication for Benzathine penicillin G and how is it given?

A

syphilis (T.pallidum)

IM depot injection (slow-release formulation)

19
Q

indications for natural penicillin

A
  1. streptococcal infections
  2. gram + rods (actinomyces israelii)
  3. clostridium perfringes (gas gangrene)
  4. enterococci
  5. prophylaxis against strep. agalactiae
  6. Neisseria meningitidis &gonorrhea
20
Q

side effects of natural penicillin

A
  1. hypersensitivity/ allergic reaction
  2. drug-induced hemolytic anemia (IgG-mediated)
  3. interstitial nephritis
  4. Jarisch- Herxheimer reaction- syphilis treatment
21
Q

symptoms for hypersensitivity reaction from penicillin

A

fever, urticaria, pruritus, joint swelling, angioedema, anaphylaxis (IgE-mediated)

22
Q

symptoms of Jarisch- Herxheimer reaction

A

fever, chills, flushing, hyperventilation

23
Q

list the very- narrow spectrum, β- lactamase resistant penicillins

A

Oxacillin
Methicillin
Nafcillin (IV)
Dicloxacillin

24
Q

list the broad spectrum, β- lactamase sensitive penicillins

A

Ampicillin

Amoxicillin

25
Q

name 2 extended-spectrum, β- lactamase sensitive penicillins and how is it given

A

Piperacillin (IV)

Ticarcillin (IV)

26
Q

when do you give Piperacillin and Ticarcillin?

A

pseudomonas (‘anti-pseudomonal peniciilins’)

sepsis

27
Q

when do we give Oxacillin?

A

staphylococcal infections–> skin &soft tissue infections, endocarditis, osteomyelitis

DO NOT COVER MRSA

28
Q

side effects of very- narrow spectrum, β- lactamase resistant penicillins

A

interstitial nephritis–> methicillin

Neutropenia –> Nafcillin

29
Q

side effects of broad/extensive-spectrum, β- lactamase sensitive penicillins

A
  1. Maculopapular skin rash (pseudoallergy) –> ampicillin given in EBV infection
  2. GI disturbances (most severe dysbacteriosis with ampicillin)
  3. Stevens- Johnsons syndrome
  4. Hepatotoxicity (amoxicillin+clavulanate)
30
Q

indications for broad-spectrum, β- lactamase sensitive penicillins

A

similar to penicillin G + ↑ activity against gram -rods
AM-CILLIN “HHELPSSS” kill enterococci
H. influenza (pneumonia,otitis media & sinusitis )
H.pylori (triple therapy)
E.coli
Listeria monocytogenes
Proteus mirabilis (Uncomplicated UTI)
Salmonella
Shigella
S. Pneumoniae (otitis media & sinusitis )

also: anaerobic infections, Borrelia Burgdorferi (lyme)
prophylaxis: high-risk patients prior to dental procedures, asplenic patients with fever

Pharma 2nd semester (49 decks)

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