lecture class notes on carbapenems and monobactams

1. CARBAPENEMS
Dr.Deepak Daniel
Dept. of Pharmacology
GTDMCA

2. Objectives of this session-
•Describe the mechanism of action, antibacterial spectrum,
uses and side effects of Carbapenems.
•Name some important Carbapenems.

3. CARBAPENEMS
•Beta lactam antibiotics.
•Valuable reserve antimicrobials.
•“Drugs of last resort”.

4. Antibacterial Spectrum:
• Wide antibacterial spectrum.
• Post antibiotic effect against gram –ve bacteria.

5. Mechanism of Action:
• Inhibit bacterial cell wall synthesis similar to
penicillins.
• Highly resistant to most beta lactamases
including ESBL.

6. CARBAPENEMS:
• IMIPENEM
• MEROPENEM
• ERTAPENEM
• FAROPENEM

7. IMIPENEM
•Derivative of thienamycin.
•First member of this class.
•Extremely potent.
•Broad spectrum beta lactam antibiotic.
•Not absorbed orally.
•T ½ - 1 hour.

8. Limitation :
• Rapid hydrolysis by enzyme dehydropeptidase (dipeptidase)
present in renal proximal tubule.
• Forms metabolites toxic to renal tubules.
• Combined with cilastatin, a reversible inhibitor of
dehydropeptidase .
• Always used in combination with cilastatin as FDC.

9. Uses :
• UTI ( including Pseudomonas)
• Pneumonia ( including resistant Streptococci)
• Skin, soft tissue, bone and joint infections (Staph.aureus)
• Pelvic/abdominal infection/sepsis
• Gram negative septicemia
• Serious hospital acquired infections
Adverse effects:
 Nausea and vomiting
 Seizures at higher doses.

10. MEROPENEM
Similar to imipenem.
Not destroyed by renal dipeptidase.
Risk of seizures is less than with Imipenem.
Indications are similar to imipenem.

11. ERTAPENEM
•Similar to meropenem except it is not useful against
P.aeruginosa.
•Longest t ½ of 4 hrs amongst carbapenems - given once
daily.

12. FAROPENEM
Orally effective
Good efficacy against both gram positive and gram
negative organisms and some anaerobes.
Bacterial sinusitis, CAP and genitourinary infections.

13. Monobactams
•AZTREONAM
•MOA  Binds to specific PBP  inhibits cell wall
synthesis
•Bactericidal

14. Spectrum
• Aerobic gram –ve bacteria
• No activity against gram +ve bacteria or anaerobes.
• Resistant to many β lactamases except extended spectrum β
lactamases .

15. Pharmacokinetics
• Oral BA poor  IM /IV
• Inhalational Aztreonam – Cystic Fibrosis due to P. aeruginosa
• Achieves therapeutic conc. in CSF in the presence of inflamed
meninges  alternative to cephalosporins in the Rx of meningitis
caused by gram –ve bacilli
• Excreted in the urine

16. Adverse Effects
• Skin rashes
• Rise in serum aminotransferases

17. To summarize
•Important drugs under carbapenems
•Limitation of imipenem
•Advantages of meropenem over imipenem
•Carbapenem with longest t ½
•Orally effective carbapenem
•Aztreonam- spectrum of action, pharmacokinetics .

18. THANK YOU
HAVE A GREAT DAY !!