Term
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Definition
A monobactam (B-lactam ring is not fused to another ring). It is the only monobactam available.
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Term
| What are advatages of Aztreonam? |
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Definition
1. Resistant to B-lactamase
2. Non-nephrotoxic, non-ototoxic; good alternative to aminoglycosides (nephrotoxic)
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Term
| What are clinical uses of Aztreonam? |
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Definition
Active against Gram- aerobic organisms ONLY, including P. aeruginosa (very narrow spectrum of activity) |
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Term
| How are carbapenems administered? |
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Definition
Parenteral administration. |
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Term
How is imipenem different from the other carbapenems?
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Definition
It lacks a key methyl group, so it is sensitive to cleavage by dehydopeptidase in the kidney. It must be administered with cilastatin to prevent this cleavage. |
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Term
| What are advantages of carbapenems? |
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Definition
1. Very broad spectrum: Gram+ and Gram-, aerobes and anaerobes
Note: Not good against MRSA or E. faecium
2. B-lactamase resistant
Note: Still, B-lactamase is the main mechanism of resistance to carbapenems
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Term
What is the clinical use of carbapenems?
(Imi-, Mero- Erta- and Doripenem)
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Definition
Very broad spectrum:
- intraabdomincal infections
- polymicrobial infections
- P. aeruginosa
- neutropenic fever
Notably ineffective against:
- MRSA
- E. Faecium
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Term
| What are some adverse effects of Carbapenems? |
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Definition
GI effects
Injection site irritation
Hypersensitivity (rash, anaphylaxis)
CNS effects: headache, seizures (meropenem is safest in this regard)
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Term
| How are carbapenems distributed, metabolized, and excreted? |
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Definition
Distributed widely to most body tissues (like with penicillins, CSF penetration increases when meninges are inflamed).
Not metabolized (except imipenem is hydrolyzed in kidney); excreted renally.
Note: Imipenem is cleaved by dehydropeptidase in kidney if not administered with cilstatin.
Note: Ertapenem has longest half-life (~4hr), so lower dosing.
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Term
| Are B-lactams bateriostatic or bactericidal? |
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Definition
Bactericidal. (Includes penicillins, cephalosporins, carbapenems and aztreonam.) |
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Term
| Which B-lactams are B-lactamase resistant? |
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Definition
1. 3rd and 4th generation cephalosporins
2. Carbapenems
3. Aztreonam
4. B-lactamase resistant penicillins
- methicillin
- naficillin
- oxacillin
- cloxacillin
- dicloxacillin
5. Combo penicillin + B-lactamase inhibitor
-Augmentin
-Unasyn
-Zosyn
Timentin
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