L27- β-lactams: Penicillins Flashcards

1
Q

list the cell wall synthesis inhibitors

A

β-lactams: penicillins, cephalosporins, carbapenems, monobactams

vancomycin
daptomycin
bacitracin

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2
Q

Cell wall synthesis inhibitors require (1) and (2) from bacteria in order to work well. Due to the nature of their target, (3) is an important advantage.

A

1- peptidoglycan cell wall [inactive for mycoplasma, protozoa, fungi, viruses]

2- actively proliferating cells (cell wall synthesis must be occurring

3- selectively toxic –> target not in humans, therefore minimal AEs

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3
Q

define:

  • (1) peptidoglycan

- (2) PBPs

A

1- polysaccharide and polypeptide chains cross-linking to form cell wall

2- transpeptidases in bacteria involved in last step of cell wall synthesis –> target for β-lactams

  • number varies with organism type
  • resistance may develop if PBP mutates
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4
Q

list the β-lactams, include structure, MOA

A
  • penicillins, cephalosporins, carbapanems, monobactams
  • β-lactam ring
  • Bactericidal: inhibits PBP, last step of cell wall synthesis –> activates autolytic enzymes –> lysis / cell death
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5
Q

(1) are bacterial enzymes that are responsible for the hydrolysis of β-lactams. (2) is the important bacteria species that is resistant to β-lactams due to presence of (1). Although (1) don’t work on (2), (3) will be effective even though MOA is similar. (4) may be given to assist β-lactams if bacteria have (1).

A

1- β-lactamases: penicillinases, cephalosporinases

2- S. aureus (penicillinase)

3- cephalosporins

4- β-lactamase inhibitors

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6
Q

β-lactamase inhibitors:

  • (1) list drugs
  • (2) definition
  • (3) uses
A

1- clavulanic acid, sulbactam, tazobactam, avibactam (all are specific to one β-lactam)

2- agents with β-lactam, but no significant antibacterial activity

3- used in fixed combinations with specific drugs – binds most β-lactamases to prevent β-lactam inactivation

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7
Q

describe the advantage of β-lactam + protein synthesis inhibitor combination, include how to administer

A

(synergistic combination)
-β-lactam destroys cell wall –> allows other drugs to enter cell (facilitates movement through cell wall)

-must be infused separately (different IVs) or they will form inactive complex

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8
Q

Penicillins:

  • (narrowly/widely) effective
  • (high/low) toxicity
  • (high/low) bacterial resistance
  • (4) entry in Gram+ cells
  • (5) entry in Gram- cells
A

1- widely effective
2- low toxicity
3- high / increasing levels of resistance

4- easily passes thru cell wall - more effective
5- must utilize outer membrane porins to enter cell - less effective

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9
Q

The ability for penicillins to ‘reach’ PBPs is determined by the following characteristics…

A
  • size (smaller better)
  • charge (neutral better)
  • hydrophobicity (highly better)
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10
Q

list the mechanisms of Penicillin resistance by bacteria (hint- 4)

A
  • inactivation via β-lactamases
  • modification of PBPs
  • impaired penetration of drug to target PBPs
  • increased efflux via p-glycoprotein pumps
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11
Q

Penicillin G = (1):

  • (2) route of administration
  • active against (3) bacteria
  • susceptible to (4)
A

1- benzylpenicillin
2- IV, IM (not oral)
3- Gram+ cocci/rods, Gram- cocci, most anaerobes
4- β-lactamase inactivation

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12
Q

Penicillin G is the drug of choice for….

A

(mainly Gram+ organisms)
-Syphilis, Treponema pallidum (benzathine penicillin G)

  • Strep infections
  • susceptible pneumococci
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13
Q

name and define the 2 repository penicillins (with G)

A

penicillin G procaine
penicillin G benzathine

-local anesthetics with penicillin given IM to prolong duration of action of penicillin G (dec dosing)

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14
Q

penicillin G procaine:

  • (1) route of administration
  • (2) half life
  • (3) uses
A

1- IM (IV would => procaine toxicity)

2- 12-24hrs

3- seldomly used due to increased resistance

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15
Q

penicillin G benzathine:

  • (1) route of administration
  • (2) half life
  • (3) uses
A

1- IM

2- 3-4 wks [NOTE- must check for possible hypersensitivty before use due to long duration]

3- Syphilis (T. pallidum), rheumatic fever prophylaxis (Strep. pyogenes)

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16
Q

Penicillin V:

  • (1) and (2) are the main difference in comparison to penicillin G
  • drug of choice for (3)
  • also used for (4)
A

1- more acid stable –> given orally

2- less active against Gram- bacteria

3- Strep. pharyngitis

4- mild-moderate infections: pharyngitis, tonsilitis, skin infections (Strep. spp.)

17
Q

Anti-staphylococcal Penicillins:

  • (1) list drugs
  • (2) key property, although inactive against (3)
  • (4) uses
A

1- nafcillin, oxacillin, dicloxacillin

2- β-lactamase resistant
3- MRSA

4- β-lactamase producing staphylococci

18
Q

list the anti-staphylococcal penicillins

A

nafcillin
oxacillin
dicloxacillin

19
Q

Extended Spectrum Penicillins:

  • (1) list drugs
  • similar to actions to (2) agent, with additional (3) activity
  • susceptible to (4) therefore activity enhanced with (5)
A

1- ampicillin, amoxicillin

2- penicillin G
3- Gram- activity

4- β-lactamases
5- β-lactamase inhibitor

20
Q

______ is the penicillin with the highest oral bioavailability

A

amoxicillin (even over ampicillin)

21
Q

______ is a common antibiotic prescribed for children and pregnant patients

A

amoxicillin

22
Q

(1) is the drug of choice for prophylaxis after dog, cat, human bite
(2) is the drug of choice for infection after dog, cat, human bite

A

1- (augmentin) amoxicillin + clavulanic acid, oral

2- ampicillin + sulbactam, IM

23
Q

discuss general clinical uses of Amoxicillin, include route of administration

A
  • oral

- *URIs, acute otitis media, Strep. pharyngitis, pneumonia, skin infections, UTIs

24
Q

discuss general clinical uses of Ampicillin, include route of administration

A
  • IV (version of amoxicillin)

- acute otitis media, Strep. pharyngitis, pneumonia, skin infections, UTIs

25
Q

Anti-pseudomonal Penicillins:

  • (1) list agents
  • effective against (2) bacteria
  • usually used with (3)
A

1- ticarcillin, pipercillin

2- Gram+/- bacilli

3- β-lactamase inhibitor

26
Q

Ticarcillin, Piperacillin are commonly used to treat (1) infections. (2) is the general main clinical use (include route of administration) for (3) infections.

A

(anti-pseudomonal penicillins)
1- Pseudomona Aeruginosa

2- IM for susceptible Gram- bacteria

3- moderate-to-severe infections of susceptible bacteria: un-/complicated skin infections, GYN / intra-abdominal infections, febrile neutropenia [mixed infections generally]

27
Q

Penicillins Pharmacokinetics:

  • (1) half-life, except for (2) types
  • absorption via oral administration can be disrupted by (3); (4) penicillin oral bioavailbility is described as erratic
A

1- 30-60 mins
2- repository penicillins

3- food
4- nafcillin

28
Q

Penicillins Pharmacokinetics:

  • successfully distributed to (1) body fluids
  • only (2) are found in bile
  • (3) do not receive sufficient penicillin concentration; (4) is the exception
A

1- (most) pleural, pericardial, peritoneal, synovial fluids, urine

2- nafcillin, pipercillin, ampicillin

3- prostate, eye, *CSF
4- meningitis –> BBB is leakier

29
Q

penicillins are mainly excreted via (1), (2) is the exception

A

1- kidney / urine (don’t use in CKD)

2- Nafcillin in bile

30
Q

(1) is the main or perceived highest concern with use of penicillins, where (2) is the major determinant. (3)% of people ‘claim’ allergy to penicillin with (4) as symptoms. (5) reactions can also occur between β-lactam antibiotics.

A
1- hypersensitivity
2- penicilloic acid
3- 5%
4- ranges from rash to anaphylaxis
5- cross-allergic reactions
31
Q

Penicillin AEs:

  • (1) is most common
  • (2) can cause pseudomembranous colitis
  • (3) can cause maculopapular rash (not allergy)
A

1- GI disturbances: diarrhea

2- ampicillin
3- ampicillin, amoxicillin (rash if given to Pts with viral disease)

32
Q

Penicillin AEs:

  • (1) via methicillin
  • (2) via nafcillin
  • (3) via oxacillin
  • (4) via ticarcillin
  • (5) via penicillin G, V
  • (6) in epileptics
  • (7) development in general after use of any penicillin
A
1- interstitial nephritis
2- neutropenia
3- hepatitis
4- hematological toxicity
5- pos. Coombs test (Abs against RBCs)
6- neurotoxicity
7- secondary infections (eg. candidiasis)