Page 84 - MNU-PM502- Pharmaeutical Microbiology Theoritical Book

Pharm D- Clinical Pharmacy Program Third Level Pharmaceutical Microbiology& Antimicrobials (PM 502)

➢ In more stable clinical circumstances, should be withheld until appropriate
specimens have been collected and submitted to the microbiology
laboratory.

3-Empiric vs. Definitive Antimicrobial Therapy

Empiric antibiotic therapy is antibiotic therapy commenced before the
identification of the causative micro-organism is available (requires 24-72 hrs.).

a common approach is to use broad-spectrum antimicrobial agents as initial
empiric therapy with the intent to cover multiple possible pathogens

Combination therapy may be used as empiric therapy to ensure that at least 1
of the administered antimicrobial agents will be active against the suspected
organism

Definitive antibiotic therapy

When more information is known (as from a blood culture), treatment must be
changed to a narrow-spectrum antibiotic which more specifically targets the
bacterium known to be causing disease.

Definitive antibiotic therapy

• reduce cost

• reduce toxicity

• prevent the emergence of antimicrobial resistance in the community.

4-Host Factors to Be Considered in Selection of Antimicrobial Agents:

A “one size fits all” approach is not appropriate. There are many host factors that
may affect the selection:

• Renal and Hepatic Function: (reducing or increasing dose)
• Age: Most pediatric drug dosing is guided by weight.

In geriatric patients, the serum creatinine level and the creatinine
clearance should be considered.

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