antibioticsbooks

38 PART 1 Antibiotic Therapy
done in clinical practice. Table 4–2 lists drugs and
indicates whether they are generally considered
bacteriostatic or bactericidal; however, it should
be noted that this activity can vary based on the
pathogen being treated, the achievable dose, and
the growth phase of the organism.
Pharmacokinetic/Pharmacodynamic
Relationships
Besides differing in whether they kill microorganisms
or merely inhibit their growth, antibiotics
also differ in how they manifest their effects
over time. Careful studies have revealed that
for certain antibiotics, activity against microorganisms
correlates with the duration of time
that the concentration of the drug remains above
the MIC (time-dependent activity). For other
antibiotics, antibacterial activity correlates not
Table 4–2
Antibiotic Pharmacodynamic Parameters
Antibiotic Class Cidal or Static
Predictive PK/PD
Parameter
Penicillins
Bactericidal
Time . MIC
Cephalosporins
Carbapenems
Monobactams
Vancomycin Bactericidal (slowly) AUC/MIC
Fluoroquinolones Bactericidal
Peak: MIC
Aminoglycosides
Metronidazole
Daptomycin
Macrolides
Tetracyclines
Linezolid
Bacteriostatic
AUC/MIC