Drugs that weaken cell walls: monobactam, carbapenems, cephalosporins, glycopeptides, fosfomycin

Question 1

What is Monobactam - Aztreonam (Azactam) active against?

Answer 1

• Gram - organisms
• Covers PSEUDOMONAS
• Used in infections with multiple drug resistance - reserved agents

Question 2

MOA Of Monobactam - Aztreonam (Azactam) (3)

Answer 2

1) Binds to PBP
2) inhibits cell wall synthesis
3) promotes cell lysis and death

Question 3

ADR, Cross reactivity and metabolism/ excretion of Monobactam - Aztreonam (Azactam)

Answer 3

• little to no allergy cross reactivity with penicillins or cephalosporins
• ADR:
• neutropenia- particularly in children*
• increased liver enzymes (ALT, AST)
• metabolism/ excretion: renal adjustments needed but no hepatic adjustment needed

Question 4

Monobactam drug

Answer 4

Aztreonam (AZACTAM)

Question 5

Carbapenem drugs

Answer 5

1) Doripenem
2) imipenem/cilastatin
3) meropenem (merrem)
4) Ertapenem (invanz)
DIME DRUGS

Question 6

Use for carbapenems

Answer 6

• extremely broad spectrum antibiotics- restricted by most institutions
• reserved for infectious disease consult or positive culture/ susceptibilities
• MSSA, GP, GN, Pseudomonas, Anaerobes
• ertapenem doesn’t do pseudomonas

Question 7

Doripenem, imipenem, and Meropnem use and dosage

Answer 7

Cover MSSA to PSEUDOMONAS

• dosed 2-3 times a day
• COVERAGE OF ANAEROBES

Question 8

Ertapenem use

Answer 8

no PSEUDOMONAS COVERAGE, but dosed ONCE daily

• used outpatient infusion drug for MDR gram negative
• COVERAGE OF ANAEROBES

Question 9

CRE

Answer 9

carbapenem resistant enterobacteriaceae

- most resistant bacteria out there

Question 10

cross reactivity of carbapenems

Answer 10

little to no cross reactivity with cephalosporins or penicillins. get a decent amount of use because of drug allergies

Question 11

metabolism/ excretion of carbapenems

Answer 11

renal adjustments needed but no hepatic adjustment needed

Question 12

Cephalosporins uses

Answer 12

• MOST WIDELY USED GROUP OF ANTIBIOTICS

- beta lactam antibiotics, structure similar to penicillin

Question 13

Cephalosporin MOA

Answer 13

1) Bind to PBP

2) disrupt cell wall synthesis causing cell lysis

Question 14

Cross reactivity of cephalosporins

Answer 14

Cross reactivity of cephalosporins to penicillin is low. More likely that they are allergic to two different antibiotic classes that truly cross react. most likely cross reactive at the first generation

Question 15

First generation of Cephalosporin (2)

Answer 15

1) Cephalexin (keflex)
2) cefazolin (ancef)
- used for surgical prophylaxis, skin soft tissue infections
- major use of keflex against UTI
(MSSA, Gram + and some Gram -)

Question 16

Second generation of Cephalosporin (1)

Answer 16

Cefuroxime

• oral agent used in many types of infections - a lot of respiratory bacterial infections when cultures never resulted
• (MSSA, Gram +, Gram -)

Question 17

3rd generation of cephalosporin (3)

Answer 17

1) Ceftriaxone (Rocephin)
2) Ceftazidime
3) Cefdinir
(one, dime, (to) dinner)
- rocephin is VERY COMMON used against community acquired pneumonia, UTI, and Gram - bacteremia, meningitis
- ceftazidime- pseudomonal coverage
- cefdinir- oral similar to cefuroxine in use
- (all= gram - and some gram +)

Question 18

4th generation cephalosporin (1)

Answer 18

• think PSEUDOMONAL COVERAGE
  1) cefepime (maxipime)
• similar uses to piperacillin/tazobactam (zosyn), except NO ANAEROBIC COVERAGE.
  (MSSA, Gram +, Gram -, Pseudomonas)
• does not have same risk of nephrotoxicity so use in combo with Vanco
  -(pime is close to p in piperacillin and they have similar action)

Question 19

5th generation cephalosporin (1)

Answer 19

1) Ceftaroline (rarely used)- MRSA COVERAGE
2) ONLY Cephalosporin that has MRSA coverage
(MRSA, MSSA, Gram +, Gram -, Pseudomonas)

like 4th generation (ceftapime + mrsa), no anaerobe coverage

Question 20

What are glycopeptides

Answer 20

• group of antibiotics with Gram + activity, used primarily in:
  1) MRSA
  2) patient with PCN allergies
  3) C. diff infections
• no GRAM - coverage*
• vancomycin is the primary agent in this class
• (MRSA, MSSA, Gram +)

Question 21

MOA of glycopeptides

Answer 21

1) inhibit cell wall synthesis –> promoting bacterial lysis and death

Question 22

Route of administration for glycopeptides

Answer 22

• poor oral absorption

- all are IV except vancomycine for C. diff treatment

Question 23

Vancomycin uses

Answer 23

• used frequently in cellulitis cases as it covers staph and strep until cultures are resulted and G + bacteremia
• also used for fair amount in pneumonia

-MRSA, MSSA, Gram +

Question 24

ADRs for vancomycin (3)

Answer 24

1) nephrotoxic - renal failure
- need to have blood level monitoring and adjustment
2) RED MAN SYNDROME- rapid infusion can cause histamine release (flushing, rash, pruritis, tachycardia, hypotension)
3) Thrombocytopenia - decreased platelets

Question 25

Routes for Vancomycin

Answer 25

-IV for all indications EXCEPT c/difficile (oral)

Question 26

Fosfomycin (monurol) indications

Answer 26

Uncomplicated UTI.
ONLY effective in the bladder- not for pyelonephritis or other systemic infection
- also by IV for “compassion use”
- covers pseudomonas, GNR, enterococcus (even VRE), Gram +

Question 27

MOA of Fosfomycin (monurol)

Answer 27

inhibits bacterial cell wall synthesis

Question 28

Routes for fosfomycin (monurol)

Answer 28

oral packet - dissolve in water- dosed with one dose with option of repeat dose in 48-72 hours

Question 29

ADR of fosfomycin (monurol)

Answer 29

Well tolerated. no adr