its about pk pd of antibiotics

1. Kill characteristic of antibiotics
Dr. (Prof.)Santosh Kumar Bhaskar

2. Audience question
● With regards to antibiotic dosing:
● Look at the diagram below, representing antibiotic drug
concentration versus time, and answer the questions below:

3. ● At a basic level, the activity of antibiotics is described by three
statements, according to the most important factor in their
pharmacokinetics:
I. Antibiotics which kill over time (according to time spent over
MIC)
II.Antibiotics which kill by concentration (according to highest
peak of concentration)
III.Antibiotics which kill by a combination of time and
concentration.

6. The antibiotics most affected by this are those which kill
bacteria most effectively when the bacteria are about to divide
Examples of this include β-lactams, carbapenems,
monobactams, linezolid, linocosamides like clindamycin, and
erythromycin.

9. Concentration dependent killing is a property of antibiotics
which disable some sort of crucial step in bacterial
metabolism or protein synthesis.
The higher the concentration reached, the more synthetic
enzyme molecules are inhibited.
Examples include aminoglycosides, metronidazole,
daptomycin, and to a lesser extent fluoroquinolones.

11. As an example of pharmacokinetics, for aminoglycosides to obtain
a clinical response of around 90%, the peak level
needs to exceed the MIC by eight to ten times.
Aminoglycosides killing is initially related to passive ionic binding
of the drug to the bacterial lipopolysaccharide coats, but later it
becomes more reliant on active uptake of the drug into the
bacterial cell.
Aminoglycosides killing is initially related to passive ionic binding
of the drug to the bacterial lipopolysaccharide coats, but later it
becomes more reliant on active uptake of the drug into the
bacterial cell.

14. It is a property of those drugs which inhibit steps in DNA
synthesis or replication, or other bacterial components which
are crucial to cellular division.
Examples include fluoroquinolones, azithromycin, tetracyclines,
glycopeptides like vancomycin and teicoplanin, tigecycline,
quinupristin/dalfopristin. and to some extent linezolid.
Fluoroquinolone concentrations in serum need to average
about four times the MIC for each 24 hours to produce virtually
100% survival in a variety of experimental animal infections.