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PHARM/MHD EXAM - 3 > L5 Pharm: Cephalosporins/Carbepenems/Monobactam > Flashcards

L5 Pharm: Cephalosporins/Carbepenems/Monobactam Flashcards

1
Q

Beta-lactam Characteristics

  1. Bacteriostatic or Bactericidal?
  2. Mechanism of Action?
  3. Half life- short or long?
  4. Eliminated by what organ?
  5. Cross allergenicity -except _______?
A
  1. Bactericidal
  2. Inhibit cell wall synthesis
  3. Typically short half life (except Cephalosporin & one Carbapenem)
  4. Eliminated unchanged by the kidney (except nafcillin, oxacillin, ceftriaxone, cefoperazone)
  5. Cross allergenicity except aztreonam
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2
Q

Cephalosporins

  1. Beta lactam ring connected to what structure?
  2. Cephamycins have a methoxy group at C7 that are active against what bacteria group?
A
  1. Beta lactam ring connected to 6-membered dihydrothiazine ring
    * *Confers greater stability against many beta-lactamase enzymes that render penicillins inactive**
  2. Anaerobes
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3
Q
  1. How do Cephalosporins interfere with cell wall synthesis?

2. What are the 3 primary mechanisms of resistance to cephalosporins?

A
  1. Interfere with cell wall synthesis by binding to PBP (transpeptidases)
    - Inhibition of PBPs leads to inhibition of the final transpeptidation step of PG synthesis
  2. Bacteria confer resistance by:
    - Production of B-lactamase enzymes (many gram negative, some gram positive and anaerobic bacteria)
    - Change PBP protein- decrease binding affinity
    - Gram negative can change porin- inability of antibiotic to reach PBP target due to poor penetration through outer membrane
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4
Q
  1. How are Cephalosporins grouped?

2. What are divisions based upon?

A
  1. Generations (5 total)
  2. Cephalosporins divided into Generations based on:
    - Antimicrobial activity
    - Resistance to Beta Lactamase
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5
Q

First Generation Cephalosporins

  1. Best activity against what bacteria group?
  2. Good activity against a few…?
  3. What are the two most common ones used?
A
  1. Gram Positive Aerobes
    - MSSA
    - Penicillin Susceptible S. Pneumoniae
    - Group Streptococci
    - Viridians Streptococci
  2. Good activity against a few gram negative aerobes (PEK)
    - P. Mirabilis
    - E. Coli
    - K. Pneumoniae
  3. Cefazolin & Cephalexin
    * = bolded in the handout
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6
Q

Second Generation Cephalosporins

  1. What are the three subgroups?
  2. Compared to First Generation: less active/more active against what bacteria?
  3. What subgroup has activity against anaerobes?
A
  1. Cephalosporins, Cephamycins, Carbacephems
  2. Less active against gram positive aerobes (staphylococci and streptococci- MICs are higher)
    - More active against gram-negative aerobes
  3. Cephamycins target anaerobes
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7
Q

Second Generation is more active against gram-negative aerobes, such as:

A
  • H. Influenzae
  • Enterobacter spp. (some)
  • Neisseria spp.
  • P. Mirabilis
  • E. Coli
  • K. Pneumoniae

(Hint: HENPEK)

Also have expanded coverage against Moraxella Catarrhalis

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8
Q

Second Generation Cephalosporins

  1. The cephamycins (cefoxitin, cefotetan, and cefmetazole) are the only cephalosporins that have activity against what species?
  2. Cephamycins can be used as a prophylaxis before what type of surgery?
A
  1. Anaerobes
    - Bacteroides fragilis
    - Bacteroides fragilis group
  2. Prophylaxis before abdominal surgery- kills anaerobic bacteria
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9
Q

Cefuroxime, Cefprozil and Cefoxitin belong to what generation of Cephalosporins?

A

Second Generation

  • expanded gram negative aerobic coverage
  • anaerobic coverage (bacteriodes group)
  • less gram + coverage than first generation
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10
Q

Cefoxitin, Cefotetan, and Cefmetazole are apart of the __________ subgroup of ____________ generation cephalosporins.

A

Cephamycin subgroup of 2nd generation

-kill anaerobic bacteria

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11
Q

How do Third Generation Cephalosporins compare to first and second generation with regards to gram +/- bacteria?

A
  • Less active than 1st or 2nd generation agents against gram positive aerobes
  • Enhanced activity against gram negative aerobes, including B-lactamase producing strains
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12
Q

What two 3rd Generation Cephalosporins can be given to treat pseudomonas aeurginosa?

A

ONLY ceftazidime and cefoperazone

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13
Q

Does Ceftriaxone have activity against pseudomonas?

A

NO.

-Only 3rd generation that do: Ceftazidime and Cefoperazone

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14
Q

Ceftriaxone and Cefotaxime have the best activity against what type of aerobes?

A
  • Gram postive aerobes.
  • 3rd generation Cephalosporins- these two drugs have less activity against gram positive agents than 1st or 2nd generation cephalosporins
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15
Q
  1. Third generation Cephalosporins have bactericidal activity against what gram negative aerobes?
  2. Do they have activity against anaerobes?
A

H. Influenzae, E. Coli, Neissiera meningitis and gonorrhea (including B-lactamase producing strains), P. Mirabilis, Enterobacter spp., Citrobacter spp., Salmonella, Shigella, Serratia Marcescens

Pseudomas Aeruginosa is only treated with Ceftazidime and Cefoperazone

  1. Very little activity against anaerobes
    - Ceftizocime has marginal activity
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16
Q

Ceftriaxone, Ceftazidime, and Cefpodoxime are commonly used….

A

Third Generation Cephalosporins

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17
Q

Select 3rd generation cephalosporins are strong inducers of what enzymes found in gram-negative aerobic bacteria (Enterobacter spp)?

A

Extended Spectrum B-Lactamases (Type 1 or Class C)

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18
Q

Fourth generation Cephalosporins

  1. Extended spectrum of activity against what species? What species are not covered?
  2. What is an example of a 4th generation Cephalosporin?
  3. Good or poor inducer of Extended Spectrum Beta Lactamases?
  4. How stable are 4th generation Cephalosporins against B-lactamase hydrolysis?
A
  1. Extended spectrum of activity against gram positive and gram negative aerobes
    - Gram positive aerobes: coverage against staphylococci and streptococci similar to ceftriaxone and cefotaxime
    - Gram negative aerobes: similar coverage to 3rd generation, but has activity against:
    - Pseudomonas Aeruginosa & B-lactamase producing Enterobacter & E.Coli
  2. Cefepime (only drug listed)
  3. Poor inducers
  4. Excellent stability (most stable against b-lactamase)
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19
Q

Unlike Penicillins, what bacteria are Cephalosporins NOT active against?

A
  • MRSA
  • Coagulase Negative Staphylococci
  • Enterococcus spp.
  • Listeria monocytogenes, Legionella pneumonia, C. diff (atypical bacteria- intracellular pathogens)
  • Stenotrophonomonas maltophilia
  • Campylobacter jejuni
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20
Q

Cephalosporins

  1. How well are they absorbed?
  2. Distribute where? What generation distributes to CSF?
  3. How are they eliminated? What are they exceptions?
  4. Long or short half life?
A
  1. Well absorbed orally from GI tract, serum concentrations lower than IV dosing
    * Food influences absorption
  2. Widely distributed into tissues & fluids
    - 3rd and 4th generation adequately distribute to CSF- can be used to treat meningitis (1st & 2nd generation do not reach adequate concentrations!)
  3. Renal elimination; Exceptions:
    - Ceftiaxone- biliary system
    - Cefoperazone- liver
    * Always watch renal function when giving pts these abx!
  4. Short half life (
21
Q

What type of infections are First Generation Cephalosporins used to treat?

A
  • Skin and soft tissue infections
  • Septic arthritis
  • osteomyletis
  • endocarditis
  • UTI
  • Bacteremia

Can be used as a prophylactic in surgery

22
Q

What generation Cephalosporin would you use to treat the following: sinusitis, otitis, upper and lower respiratory infections, polymicrobial infections?

A

Second Generation

  • Bactericidal to anaerobic bacteria
  • Can be used as a prophylactic in abdominal surgery

Bolded in Handout:
Second generation cephalosporins are no longer recommended in treatment of meningitis

**Cephamycins treat the whole Bactericides fragilis family & polymicrobial infections (intra-abdominal infections)

23
Q

What clinical use does 3rd Generation Cephalosporins have?

A

Used to Treat: (Bolded in Hanodut)

  • *Pseudomonas Aeruginosa- Ceftazidime or Cefoperazone
  • *Uncomplicated Gonorrhea- Ceftriaxone (single IM dose)
  • *Pen-Resistant Strep. Pneumoniae (meningitis, pneumonia)- Use Cefotazime and Ceftriaxone

Others:

  • Bacteremia
  • Pneumonia
  • Complicated UTI
  • Abdominal infection
  • Bone and joint infection
  • Meningitis
24
Q

What is an important property of Cefepime? What other infections does it treat?

A

Anti-Pseudomonal Activity

Also Treats: community & nosocomial acquired pneumonia, bacteremia, uncomplicated & complicated UTIs, skin & soft tissue infections, intraabdominal infections, empiric therapy for febrile neutropenia

25
Q
  1. What drug is a 5th generation Cephalosporin?
  2. What two gram positive strains does it have activity against?
  3. What is it used clinically to treat?
  4. What is important in really impaired patients?
A
  1. Ceftraoline
  2. Activity against staphylococcus and streptococcus, including multi drug resistant pneumococcus and MRSA
  3. Clinically: CA-pneumonia, skin & skin structure infections
  4. DOSE ADJUST in renally impaired patients
26
Q

Adverse Effects- Cephalosporins

  1. Hypersensitivity: _____%
  2. What patient population does hypersensitivity reactions to cephalosporins typically occur in? What is the degree of cross reactivity (%)?
A
  1. Hypersensitivity: 5%
  2. Rxns occur most frequently in pts with penicillin allergy
    - Cross Reactivity- 5-15%
  • If a patient has an IgE mediated response to penicillin, DO NOT give cephalosporins!*
  • If a patient just gets a rash/pruritus- give other beta-lactams with caution keeping in mind the degree of cross reactivity*
27
Q

Adverse Effects- Cephalosporins
1. Some cephalosporins have a NMTT side chain- what unique adverse effects can these produce?

  1. What 5 Cephalosporins have this side chain?
A
  1. ->Hypoprothrombinemia
    - With or without bleeding, due to blocking of an enzyme in Vit. K metabolism or reduction of Vit. K producing bacteria in the GI Tract
  • > Disulfiram Reaction (ethanol intolerance)
  • NMTT blocks alcohol dehyrdogenase
  1. Cefamandole, Cefotetan, Cefmetazole, Cefoperazone, and Moxalactam (reduces platelet aggregation that significantly increases the incidence of bleeding)
28
Q

Adverse Effects- Cephalosporins

  1. Hematologic effects?
  2. GI?
  3. Avoid giving Ceftriaxone to a patient receiving IV __________?
A
  1. Beta-Lactam Specific Cytotoxic IgG or IgM antibodies develop & bind WBC or platelets- cause cell lysis when antigen (penicillin) encountered by activation of the complement system
    - Leukopenia, neutropenia, thrombocytopenia- especially in patients undergoing long term (>2 wks) treatment
  2. GI: Pseudomembranous colitis- C. diff diarrhea Some cephalosporins may cause diarrhea that is not due to C. diff
    - Nausea/vomiting
    - Biliary sludging (ceftriaxone therapy)
    - transient increase in liver enzymes
  3. IV Calcium
    - Precipitation of Ceftriaxone with IV Calcium products- AVOID giving these two together!

Other adverse effects: phlebitis, drug fever, interstitial nephritis (rare), neurotoxicity, non convulsive status epilepticus

29
Q

Carbapenems

  1. What are the 4 Carbapenem drugs?
  2. Carbapenems have a trans configuration hydroxyl group at carbon 6 compared to the cis configuration acylamino group at carbon 6 of penicillin. What does this structural difference result in (aka how are carbapenems better than penicillins?)
A
  1. Imipenem, Meropenem, Ertapenem, Doripenem
  2. Structural change allows for:
    - Extended spectrum of activity
    - Increased antibacterial activity
    - Greater stability against most beta-lactamase enzymes (even more than cephalosporins)
    * *Question might be more detail than we need to know- might just be important to know they both have beta-lactam attached to a 5 membered ring & that trans configuration is more stable because there’s less steric hindrance- Orgo chem 101 bitches**
30
Q
  1. Do Carbapenems display time dependent or concentration dependent bactericidal activity?
  2. How do they cause cell death?
  3. What PBP do they have high affinity for?
  4. Carbapenems are small zwitterions- how does this influence their activity?
A
  1. Time-dependent (all beta-lactams)
  2. Bind PBP proteins
  3. PBP-2 (Imipenem, Meropenem, Doripenem)
  4. Small zwitterion- enable them to penetrate the outer membrane of most gram-negative bacteria and gain access to PBPs more readily
31
Q

How do bacteria confer resistance to Carbapenems?

A
  1. Alter outer membrane porins
  2. Hydrolysis of carbapenem antibiotics by beta-lactamase or carbapenamase enzymes
    - all of the carbapenems display intrinsic resistance to nearly all beta-lactamases
  3. Alterations in PBPs (decreased binding affinity)
32
Q
  1. Carbapenems are currently the most _______-spectrum (broad or narrow?) antibiotics
  2. Which 2 Carbapenems are good against gram-positive aerobes?
  3. Which 2 are the best against gram negative aerobes?
A
  1. Most BROAD SPECTRUM
    - gram +/- aerobes AND anaerobes
  2. Gram + aerobes: use Imipenem and Doripenem
    - MSSA, PSSP, Group A-C streptococcus, viridians strep, Enterococcus Faecalis only (E. Faecium are resistant)
  3. Gram Negative Aerobes- Doripenem & Meropenem are the best
    * *Carbapenems display activity against B-lactamase producing strains that display resistance to other B-lactam antibiotics**
    - E. Coli, Klebsiella spp., Serratia Marcescens, Morganella Morganii, Yersinia spp, Citrobacter freundii, Enterobacter spp, proteus spp, providencia spp, acinetobacter spp.
33
Q

All carbapenems have activity against pseudomonas except…

A

ERTAPENEM TEST

34
Q

All carbapenems display activity against gram + & - anaerobes

  1. What gram postive anaerobes?
  2. What gram negative anaerobes?
A
  1. Peptostreptococcus spp., peptococcus sp., Clostridium perfringens & tetani
    - NOT C. Diff!
  2. Entire Bacteroides family
    - Prevotella spp, Veillonella parvula, Fusobacteriums
35
Q

Carbapenems do NOT have activity against what 7 bacteria strains/species?

A
  • *TEST Q**
    1. MRSA**
    2. Coagulase negative staph
    3. Some enterococci
    4. Clostridium difficile**
    5. Stenotrophomonas maltophilia**
    6. Nocardia
    7. Atypical bacteria (Listeria, chlamydia)**
  • *=bolded in handout
  • This list was mentioned twice in lecture- she said it’s important to know*
36
Q

What carbapenem penetrates CSF best?

A
  • Meropenem*

- Penetrates better than Imipenem (only low concentrations diffuse into CSF following IV administration) & Ertapenem

37
Q
  1. What is the major route of elimination of all of the carbapenems?
  2. What carbapenem undergoes hydrolysis in the kidney? What enzyme causes hydrolysis? What drug inhibits this?
A
  1. Kidney- Urinary excretion of unchanged drug (glomerular filtration/tubular secretion)
  2. IMIPENEM
    - Undergoes hydrolysis in the kidney by DHP enzyme
    - Causes Imipenem to become inactive & potentially nephrotoxic
    - Prevent this by giving Imipenem with DHP-Inhibitor CILASTATIN
    - ->This prevents renal metabolism & protects against nephrotoxicity!

“Cilastin makes Imipenem last…im”

38
Q
  1. What carbapenem has the longest half life?

2. All carbapenems require dosage adjustments in patients suffering from what?

A
  1. Ertapenem- 4 hours; all others have a t1/2 of 1 hour

2. Renal dysfunction

39
Q
  1. What are three infections carbapenems are used to treat?

2. If a patient presents with pseudomonas aeruginosa, what carbapenem would NOT be used?

A
  1. Used to treat:
    - Nosocomial infections (empiric therapy)
    - Polymicrobial infections
    - Infections due to resistant bacteria- especially organisms that produce type 1 or class C beta-lactamase enzymes
  2. ERTAPENEM

Carbapenems can also be used to treat febrile neutropenia & meningitis in children

40
Q

Carbapenems

  1. Hypersensitivity- ____%
  2. Cross reactivity in patients with what allergy?
A
  1. 3%
  2. Penicillin allergy

Same rules as cephalosporins:

  • If a patient has an IgE mediated response to penicillin, DO NOT give carbapenems!*
  • If a patient just gets a rash/pruritus- give other beta-lactams with caution keeping in mind the degree of cross reactivity*
41
Q

How do Carbapenems adversely effect:

  1. GI system?
  2. CNS? What risk factors do they pose?
A
  1. GI: nausea/vomiting in 5% of patients
    - Abx associated pseudomembranous colitis (predisposes pt to c. diff)
  2. CNS: insomnia, confusion, dizziness, hallucinations, dpression
    - Increase risk for SEIZURES
    - ->Reported in 1.5% of pts receiving Imipenem, Meropenem (0.5%), Ertapenem (0.5%) and Doripenem (patients with preexisting CNS disorders are more likely to develop seizures (brain lesions, recent trauma, history of seizures)

Other adverse effects: thrombophlebitis, neutropenia, thrombocytopenia, transient LFT increases, yeast infections

42
Q

Monobactrams

  1. What is the only clinically used monobactram?
  2. Time dependent or concentration dependent killing?
  3. Can only bind to what PBP? What species does this limit monobactrams to?
A
  1. Aztreonam
  2. Time-dependent bactericidal action
  3. PBP-3, which is only found on gram negative aerobes
43
Q
  1. Is Aztreonam stable against beta lactamases?

2. What is a significant gram negative aerobe that assertional is active against?

A
  1. Aztreonam is relatively stable against hydrolysis by some plasmid/chromosomally mediated beta-lactamases
    - Hydrolyzed by some beta lactamases produced by Klebsiella, Enterobacter and pseudomonas aeruginosa
  2. Has activity against PSEUDOMAS AERUGINOSA
44
Q
  1. What is the only way Aztreonam can be administered?
  2. Does it penetrate into CSF?
  3. How is Aztreoname eliminated?
A
  1. Only administered in IV form
  2. Aztreonam is widely distributed into body tissues & fluids- DOES penetrate CSF, especially in the presence of inflamed meninges
  3. Eliminated by kidneys- unchanged in urine
    - t1/2= 1.3-2.2 hours
    * *adjust dose in patients with renal dysfunction!**
45
Q

Aztreonam is especially useful for treatment of gram-negative infections in patients with what severe allergy? Why is this?

A

Penicillin allergy. Aztreonam has no cross reactivity!

46
Q

What are the only 2 3rd generation cephalosporins that target Pen-Resistant Strep Pneumo?

What is the MOST active cephalosporin against Pseudomonas?(2 actually)

A

Ceftriaxone & Cefotaxime

CEftazidime & Cefoperazone

47
Q

What is the main clinical use for 1st generation cephalosporins?

A

Surgical prophylaxis for ABDOMINAl surgery

48
Q

______ is used for uncomplicated gonorrhea (single IM dose), CAP, PRSP, viridans strep endocarditis

A

CEFTRIAXONE

PHARM/MHD EXAM - 3 (21 decks)

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