Lecture Notes: Carbapenems - Pharmacist Academy

Introduction

• Review of the carbapenem class of antibiotics.
  • Broad spectrum activity.
  • Commonly used in clinical practice.
• Other educational videos available:
  • Introduction to infectious diseases.
  • Reviews of other antibiotic classes.

Mechanism of Action

• Beta-lactams:
  • Inhibit bacterial cell wall formation.
  • Bind to penicillin-binding protein (transpeptidase).
  • Bactericidal effect as they kill bacteria.

Clinical Use

• Broad Spectrum of Activity:
  • Useful for empirical therapy.
  • Covers a wide range of bacteria including resistant organisms.
  • Use until specific culture results are available.
• Commonly used for:
  • Intra-abdominal infections.
  • Urinary tract infections (especially ESBL-producing organisms).
  • Diabetic foot infections.
  • Pneumonia.

Pharmacokinetics

• Time-dependent activity:
  • Effectiveness related to time concentration is above MIC (Minimum Inhibitory Concentration).

Side Effects and Monitoring

• Risk of seizures.
  • Highest among beta-lactams.
  • More prevalent if renal function impaired or incorrect dosing.
• Other side effects:
  • Diarrhea, rash, bone marrow suppression.
• Monitoring:
  • Check culture results to deescalate therapy.
  • Monitor renal function for proper dosing.

Spectrum of Activity

• Gram-Positive Coverage:
  • Staphylococcus, Streptococcus, some anaerobes.
  • Covers Enterococcus faecalis, but not faecium.
  • Does not cover MRSA or atypical organisms.
• Gram-Negative Coverage:
  • Enterobacteriaceae (e.g., E. coli, Proteus, Klebsiella).
  • Neisseria, H. influenzae, Providencia.
  • Gram-negative anaerobes.
• ESBL Infections:
  • Carbapenems are often the drug of choice.
• Pseudomonas:
  • Good activity except for Ertapenem.

Specific Carbapenems

• DIME Acronym:
  • Doripenem: Not approved for pneumonia, increased death risk.
  • Imipenem/Cilastatin: High seizure risk, needs enzyme inhibitor.
  • Meropenem: Only approved for meningitis due to CSF penetration.
  • Ertapenem: No pseudomonas coverage, more susceptible to carbapenemases, dosed once daily.

Key Takeaways

1. Broad spectrum ideal for empiric therapy.
2. Seizure risk especially in renal impairment.
3. Requires renal adjustments.

Conclusion

• Carbapenems are common and straightforward in clinical practice.
• Important to manage dosing and monitor for side effects.

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