Beta lactams Flashcards
Mechanism of Action
- Covalently (irreversibly) bind to transpeptidase
- Inhibiting cross linking
- No cell wall = cell death
PK
time/MIC
Natural Penicillins
- Penicillin G: given IV
- Penicillin V: given orally
Aminopenicillin
- Give with probenecid to slow kidney excretion
- Give with a beta lactamase inhibitor to increase spectrum
Examples of Aminopenicillins
- Ampicillin
- Amoxicillin
Beta lactamase inhibitors
- Sulbactam
- Clavulante
- Tazobactam
- Avibactam
Augmentin
-Amoxicillin + Calvulante
Unasyn
-Ampicillin + Sulbactam
Antistaphylococcal Penicillins
- Resistant to beta lactamases
- Work against MSSA
Examples of Antistaphylococcal drugs
- Oxacillin
- Methicillin
- Nafcillin
- Dicloxacillin
Nafcillin Route of Excretion
- Through the bile
- Be careful with hepatic portal hypertension (alcoholics)
Ureidopenicillins
- Antipseudomonal
- Piperacillin can penetrate outer membrane of pseudomonas
Piperacillin
-Ureidopenicillin
Zosyn
- Piperacillin + Tazobactam
- Gives gram +and - activity
Carbapenems
DIME
- Inhibit cell wall synthesis
- Have the broadest spectrum of
- Gram + and -
- Covers anaerobes
Doripenem
-Carbapenem
Imipenem
- Carbapenem
- Strong inducer of some beta lactamases
- Can cause seizures
Meropenem
-Carbapenem
Ertapenem
- Invanz
- Carbapenem
Primaxin
-Imipenem + Cilastatin
Monobactams
- Inhibit cell wall synthesis
- Only active against gram negative bugs
- Including P. aeruginosa
Aztreonam
- Monobactam antibiotic
- Covers P. aeruginosa
- Gram negative bugs only
How do we make beta lactams
- Biosynthetically (most common)
- Synthetically (rare)
Transamidase inactivation
-Beta lactam forms an ester with transamidase
Penicillins work best agains
-Rapidly growing bacteria
Why do penicillins not work orally
- They are unstable in acid
- Limits oral effectiveness
What is the only beta lactam with ZERO cross reactivity
-Aztreonam
What do beta lactamases do
- Open up the beta lactam ring so that it cannot bind to the PBP
- Abx is no longer effective
How is acid resistance achieved
- By limiting electron density on internal Oxygen nucleophile
- Increase the number of NH3s
What causes immune reactions from beta lactams
-Covalent binding to host proteins
