Beta lactams

Question 1

Mechanism of Action

Answer 1

• Covalently (irreversibly) bind to transpeptidase
• Inhibiting cross linking
• No cell wall = cell death

Question 2

PK

Answer 2

time/MIC

Question 3

Natural Penicillins

Answer 3

• Penicillin G: given IV

- Penicillin V: given orally

Question 4

Aminopenicillin

Answer 4

• Give with probenecid to slow kidney excretion

- Give with a beta lactamase inhibitor to increase spectrum

Question 5

Examples of Aminopenicillins

Answer 5

• Ampicillin

- Amoxicillin

Question 6

Beta lactamase inhibitors

Answer 6

• Sulbactam
• Clavulante
• Tazobactam
• Avibactam

Question 7

Augmentin

Answer 7

-Amoxicillin + Calvulante

Question 8

Unasyn

Answer 8

-Ampicillin + Sulbactam

Question 9

Antistaphylococcal Penicillins

Answer 9

• Resistant to beta lactamases

- Work against MSSA

Question 10

Examples of Antistaphylococcal drugs

Answer 10

• Oxacillin
• Methicillin
• Nafcillin
• Dicloxacillin

Question 11

Nafcillin Route of Excretion

Answer 11

• Through the bile

- Be careful with hepatic portal hypertension (alcoholics)

Question 12

Ureidopenicillins

Answer 12

• Antipseudomonal

- Piperacillin can penetrate outer membrane of pseudomonas

Question 13

Piperacillin

Answer 13

-Ureidopenicillin

Question 14

Zosyn

Answer 14

• Piperacillin + Tazobactam

- Gives gram +and - activity

Question 15

Carbapenems

DIME

Answer 15

• Inhibit cell wall synthesis
• Have the broadest spectrum of
• Gram + and -
• Covers anaerobes

Question 16

Doripenem

Answer 16

-Carbapenem

Question 17

Imipenem

Answer 17

• Carbapenem
• Strong inducer of some beta lactamases
• Can cause seizures

Question 18

Meropenem

Answer 18

-Carbapenem

Question 19

Ertapenem

Answer 19

• Invanz

- Carbapenem

Question 20

Primaxin

Answer 20

-Imipenem + Cilastatin

Question 21

Monobactams

Answer 21

• Inhibit cell wall synthesis
• Only active against gram negative bugs
• Including P. aeruginosa

Question 22

Aztreonam

Answer 22

• Monobactam antibiotic
• Covers P. aeruginosa
• Gram negative bugs only

Question 23

How do we make beta lactams

Answer 23

• Biosynthetically (most common)

- Synthetically (rare)

Question 24

Transamidase inactivation

Answer 24

-Beta lactam forms an ester with transamidase

Question 25

Penicillins work best agains

Answer 25

-Rapidly growing bacteria

Question 26

Why do penicillins not work orally

Answer 26

- They are unstable in acid | - Limits oral effectiveness

Question 27

What is the only beta lactam with ZERO cross reactivity

Answer 27

-Aztreonam

Question 28

What do beta lactamases do

Answer 28

- Open up the beta lactam ring so that it cannot bind to the PBP - Abx is no longer effective

Question 29

How is acid resistance achieved

Answer 29

- By limiting electron density on internal Oxygen nucleophile - Increase the number of NH3s

Question 30

What causes immune reactions from beta lactams

Answer 30

-Covalent binding to host proteins