Cell Wall Inhibitors

Question 1

penicillin G

Answer 1

penicillins:

Acid-labile

parenteral admin (IM usually)
IV for serious

Procaine and benzathine added in IM injection

Water-insoluble, slow release

Adverse Effect:

• Allergy
• Dose dep. neurotoxicity and seizures
• STEVEN JOHNSON syndrome
  
  • rashes, swelling

Question 2

penicillin V

Answer 2

penicillins:

Acid stable

Oral Admin

Absorption 65%

Question 3

oxacillin

Answer 3

beta–lactamase resistant

Hepatitis at high levels

Use to treat penicillinase containing staph and strep

Question 4

amoxicillin

Answer 4

extended spectrum

Aminopenicilin

Better absorption
- not affected by food

Prophylaxis against bac endocarditis

Question 5

ampicillin

Answer 5

extended spectrum

Aminopenicillin

Question 6

piperacillin

Answer 6

extended spectrum

Ureidopenicillin

Parenteral

Anti-pseudomonal

Reserved for severe infections caused by Klebs. and Pseudomonas
- Combo with aminoglycoside to resist resistance

Question 7

carbenicillin

Answer 7

extended spectrum

carboxypenicillin

Parenteral administration

Anti-pseudomonas

Question 8

clavulanic acid

Answer 8

beta lactamase inhibitors

Question 9

sulbactam

Answer 9

beta lactamase inhibitors

Question 10

tazobactam

Answer 10

beta lactamase inhibitors

Question 11

cefazolin

Answer 11

cephalosporins:
1st generation:

Broadest spectrum against gram + cocci

Effective against gram - bacilli

Question 12

cefuroxime

Answer 12

cephalosporins:
2nd generation:

Only group to kill ANAEROBES

Question 13

cefotaxime

Answer 13

cephalosporins:
3rd generation:

Anti-pseudomonal/pneumococcal

Serious gram - infections
Meningitis, pneumonia, gonorrhea

MOST widely used in treatment of children/infants with moderate to severe infections

Question 14

cefepime

Answer 14

cephalosporins:
4th generation:

Anti-pseudomonal

High resistance to B lactamase for treating ENTEROBACTER and PENICILLIN-RESISTANT streptococci

Question 15

imipenem

Answer 15

carbapenems:

Broadest activity

B lactam ring that binds more efficiently than pens/cephs

Resistant to B lactamases
- However, induce expression of those that affect cephalosporins and B lactams

Parenteral

Renal metabolism and inactivation

ADMINISTER WITH CILASTATIN to prevent metabolism

Question 16

meropenem

Answer 16

carbapenems

Question 17

cilastatin

Answer 17

carbapenems

peptidase inh

Question 18

aztreonam

Answer 18

monobactams:

Anti pseudomonas

Resistant to B lactamase

Gram - UTI
Lower RTIs
Systemic infection

Question 19

bacitracin

Answer 19

other:

Cell wall synth inhibitor

Depletes lipid carrier for PDG synth

TOPICAL only, poorly absorbed

NARROW (g+, Neisseria. T pallidum)

Toxicity:
- Severe nephrotoxicity

USE:

• Skin
• Opthalmologic infections

Good in combination with polymyxin B

Question 20

cycloserine

Answer 20

other

Cell wall synth inhibitor

Blocks step 2 in PDG synth
- Analog of D-ala

Oral
Good CNS penetration

Active form in URINE

Toxicity:
SERIOUS CNS
Reversible

Broad spectrum

Restricted second-line therapy for M. tuberculosis

Question 21

daptomycin

Answer 21

other

Cell membrane agent

Membrane depolarization

Bactericidal

IV administration
RENAL elimination

Vanc spectrum

Adverse effects:
- MYOPATHY

Question 22

fosfomycin

Answer 22

other

Cell wall synth inh.

Block Step 1 PDG synth
- analog PEP

Broad Spectrum (G- also)

Toxicity:
- diarrhea, vaginitis

Use:
- Oral treatment of uncomplicated UTIs (E. faecalis and E. coli)

Excreted unchanged in URINE

Question 23

vancomycin

Answer 23

other

Non-beta lactam

Mechanism:
- Binds D-ala-D-ala terminus

Blocks X linking of PDG by binding substrate

Rapidly bactericidal for dividing bacteria

Exception (static in enterococcus)

IV administration

Rarely, oral: poor absorption

Distribution excellent (bone, CNS if meninges inflamed)

Renal excretion

Narrow spectrum
Gram + mainly MRSA

Resistance:

• 2 mech:
  
  • VRE: enterococcus vanA, vanB, van C genes make different wall subunits
  • VRSA: Overexpression of D-ala-D-ala

Toxicity:

• Red man
• Ototoxicity and nephrotoxicity

Synergistic with aminoglycosides but ototoxic also

Question 24

nafcillin

Answer 24

beta-lactamase inhibitor