PK Profile

Microbiologic effect of carbapenems is determined by T>MIC

  • Microbiologic effect can be influenced by2:
    • Minimum inhibitory concentrations (MICs)
    • Pharmacokinetic profile

Carbapenems have similar PK profiles3,4

 
Parameter DORIBAX® Meropenem* Imipenem/cilastatin4
T½ (h) ∼1 ∼1 ∼1
Cmax (µg/mL) 23* 23 21-58/31-49
Elimination
(% urine recovery)
70§ 70§ 70§
Protein binding (%) ∼8 2 20/40
 
  • T½ = half-life;Cmax=maximum concentration.
  • * Mean plasma concentration in healthy subjects at the end of a single dose of
    DORIBAX® 500 mg infused over 1 h.
  • Mean plasma concentration in normal volunteers at the end of a single dose
    of meropenem 500 mg infused over 30 min.
  • Plasma concentration range at the end of a single dose of imipenem/cilastatin
    500 mg infused over 20 min.
  • § Unchanged drug for DORIBAX® and meropenem; not specified in imipenem prescribing
    information.

  • Because carbapenems have similar PK profiles, MICs often determine microbiologic effect (eg, pathogen eradication)


MICROBIOLOGIC EFFECT
OF CARBAPENEMS IS
DETERMINED BY T>MIC
"It is the time that the
concentration of free
β-lactam remains above
the MIC (TIME>MIC) for
the organism that is linked to the microbiological effect."
1
—Drusano, 2004

Pathogen eradication is harder to achieve if the MIC of the pathogen is higher rather than lower—Adapted from Drusano, 20072