Penicillins

Question 1

Penicillin MOA:

Answer 1

Inhibit bacterial cell wall synthesis.
- Blocks crosslinking of adjacent peptidoglycan strands resulting in lysis.
PCN-binding proteins (PBPs) are targets of Beta-lactam antibiotics.
- Peptidoglycan transpeptidase.

Question 2

PCN most important route of elimination:

Answer 2

Renal excretion.

- High concentrations in the urine.

Question 3

PCN absorption:

Answer 3

Food delays and decreases absorption.

- Except amoxicillin, Pen V and carbencillin.

Question 4

PCN in brain:

Answer 4

Poor distribution to brain and CSF (unless inflammation present).
- Insoluble in lipid.

Question 5

Most common hypersensitivity reaction:

Answer 5

Maculopapular rash on abdomen/trunk.

Question 6

Adverse effects of methicillin:

Answer 6

Interstitial nephritis.

Question 7

Uses for Pen G/VK:

Answer 7

Gram positive organisms:

• Staph - 99% resistant.
• Strep pneumoniae resistance.
• Gonorrhea resistance occurring.

Question 8

Anti-Staph PCNs (5):

Answer 8

IV:
- Methicillin
- Oxacillin
- Nafcillin
PO:
- Cloxacillin
- Dicloxacillin

Question 9

Aminopenicillins (2):

Answer 9

• Ampicillin

- Amoxicillin

Question 10

Aminopenicillins spectrum of activity (8):

Answer 10

Strep, enterococcus, piddly, PEK:

• Streptococcus.
• Enterococcus (drug of choice).
• Haemophilus.
• Salmonella.
• Shigella.
• Proteus.
• E. Cola.
• +/- Klebsiella.

Question 11

Carboxypenicillins (2):

Answer 11

• Carbenicillin (not made anymore).

- Ticarcillin

Question 12

Spectrum of activity for carboxypenicilins (4):

Answer 12

• Streptococcus.
• G- piddly.
• G- PEK.
• G- SPACE (pseudomonas req’s high concentrations).

Question 13

ADRs for carboxypenicillins (3):

Answer 13

• Hypersensitivity.
• Platelet dysfunction (dose dependent).
• Na+ overload.

Question 14

Ureidopenicillins (2):

Answer 14

• Mezlocillin

- Pipercillin

Question 15

Ureidopenicillins spectrum of activity (5):

Answer 15

• Bacteriodes fagilis.
• Streptococcus.
• Enterococcus.
• G- PEK
• G- SPACE

Question 16

Beta-lactamase inhibitors add coverage to (2):

Answer 16

• Staphylococcus

- Anaerobes

Question 17

ADRs for aminopenicillins (2):

Answer 17

• Hypersensitivity
• Diarrhea
  
  • Take with food to decrease symptoms.

Question 18

Complication with ticarcillin:

Answer 18

Na+ load.