Beta-lactams

Question 1

Beta-lactam antibiotics include: (5)

Answer 1

1. Penicillins
2. Penicillins with beta-lactamase inhibitors
3. Cephalosporins
4. Carbapenems
5. Monobactams

Question 2

MOA of beta-lactams:

Answer 2

Irreversible inhibition of transpeptidase which inhibits cell wall synthesis
Production of bacterial cell lysis

Question 3

Are beta-lactams bacteriostatic or bacteriocidal?

Answer 3

Bacteriocidal

Question 4

How does resistance to beta-lactams occur?

Answer 4

Bacteria may produce beta-lactamase, an enzyme that inactivates beta-lactam antibiotics

Question 5

How are beta-lactams eliminated from the body? (besides nafcillin)

Answer 5

Active renal secretion

Urinary excretion

Question 6

Patients with ______ impairment and taking _____ should have their beta-lactam does adjusted.

Answer 6

Renal 
Probenecid (prohibits secretion=incr. drug levels)

Question 7

AE of beta-lactams include:

Answer 7

Hypersensitivity (rash vs IgE mediated anaphylaxis w/in 20mins)
Cross-sensitivity among agents
GI distress

Question 8

Which other beta-lactam has a 0% cross-reactivity with Penicillins or other beta-lactams?

Answer 8

Monobactams

cephalosporins~10%, carbapenems~50% with PCN

Question 9

Naturally occurring penicillins include:

Answer 9

Penicillin G and Penicillin V

Question 10

Penicllin G IV: half life, common use, AE

Answer 10

0.5hr half life (q4 or continuous)
Neurosyphilis
Jarisch-Herxheimer (HSR-fever, chills after 1st or 2nd dose

Question 11

Repository forms of Penicillin G given IM include:

Answer 11

Bicillin L-A (benzathine only) given for syphilis (except neuro) and prevention of rheumatic fever
Bicillin C-R (benzathine and procaine)

Question 12

Naturally occurring penicillins are used for which organisms?

Answer 12

Gram +

Some gram - (meningococcus)

Question 13

When using high dose IV/IM penicillins what lab values should be monitored?

Answer 13

K and Na, at risk for accumulation

Question 14

PCNase Resistant Penicillins include: (4)

Answer 14

Methicillin
Oxacillin
Dicloxacillin
Nafcillin

Question 15

What types of organisms are PCNase Resistant Penicllins used to treat?

Answer 15

MSSA
STACN
S. pneumoniae

Question 16

What toxicities are caused by Methicillin and Oxacillin?

Answer 16

Methicillin-nephrotoxicity (interstitial nephritis)

Oxacillin- hepatotoxic

Question 17

How often is Dicloxacillin dosed?

Answer 17

PO 4x/day

Question 18

The four sub-classes of PCNs include:

Answer 18

1. Naturally Occurring
2. PCNase resistant
3. Amino Penicillins
4. Extended Spectrum

Question 19

Aminopenicillins include:

Answer 19

Ampicillin and amoxicillin

Question 20

What drug is used to treat or provide prophylaxis against Listeria?

Answer 20

Ampicillin

Question 21

Which types of organisms do Ampicillin and amoxicillin treat?

Answer 21

Enterococcus
Listeria
Gram - (ex- non-Beta lactamase producing H.influenzae, E. Coli, P. mirabilis, Salmonella, Shigella)

Question 22

How do ampicillin sulbactam and amoxicillin clavulanate differ from ampicillin and amoxicillin alone?

Answer 22

These additions provide B-lactamase inhibition, effectively broadening the spectrum of the antibiotic

(can treat- MSSA, H.influenzae, N. gonnorrhoeae, Moraxella catarrhalis, Bacteroides, E.Coli and K. pneumoniae)

Question 23

Piperacillin/tazobactam and Ticarcillin/clavulanate are examples of what?

Answer 23

Extended spectrum penicillins with beta-lactamase inhibitors

Question 24

Extended spectrum penicillins have what type of activity?

Answer 24

antipseudomonal activity

Question 25

What should be monitored in patients taking ticarcillin and why?

Answer 25

K levels, the high Na content in the med can cause hypokalemia.

Question 26

Which cephalosporins are in the 1st-5th generations?

Answer 26

1st gen: cephalexin, cefazolin
2nd gen: cefotetan, cefuroxime
3rd gen: ceftriaxone, ceftazidime
4th gen: cefepime
5th gen: ceftaroline (MRSA infections)

Question 27

Which generation of cephalosporins is lease resistant to beta-lactamase?

Answer 27

1st generation

resistance increases with generation

Question 28

How are cephalosporins different from penicillins?

Answer 28

Broader spectrum
More resistant to Beta-lactamases
Man are ineffective orally d/t to gastric acid

Question 29

Which cephalosporin has the longest half life and how is it excreted?

Answer 29

Ceftriaxone, 3rd gen (8hrs)

Biliary and renal excretion

Question 30

Which cephalosporin is best against Pseudomonas Aeruginosa?

Answer 30

Ceftazidime (3rd gen)

Question 31

Which cephalosporins have better Gram + and which have better Gram - coverage?

Answer 31

1st generations have better gram + coverage
3rd generations lose gram + coverage but gain gram - coverage
4th generation have both Gram + and - coverage

Question 32

Which generation cephalosporins have increased lipid solubility and what does that lead to?

Answer 32

3rd generation (ceftriaxone, ceftazidime), this leads to CNS penetration

Question 33

Which antibiotics do carbapenems include?

Answer 33

Ertapenem
Imipenem
Meropenem
Doripenem

Question 34

How are all carbapenems administered?

Answer 34

IV

Question 35

Why are carbapenems good for ESBL producing organisms?

Answer 35

(extended spectrum beta-lactamase)

Resistant to beta-lactamase

Question 36

What is true of the distribution of carbapenems?

Answer 36

They distribute to most tissues= treat many different sites of infection

Question 37

What is a major AE of carbapenems?

Answer 37

Seizures, especially with imipenem when predisposed to seizures already

Question 38

Why is imipenem used in combination with cilastin?

Answer 38

Imipenem is inactivated by renal dipeptidases, cilastin is a dipeptidase inhibitor.

Question 39

How is ertapenem different from other carbapenems?

Answer 39

It has a narrower spectrum of activity and is not effective against pseudomonas like the other carbapenem drugs

Question 40

Aztreonam is what kind of beta-lactam and what type of organisms is it effective against?

Answer 40

Monobactam
Effective against Gram - Pseudomonas aeruginose
(No gram + or anaerobic activity)