Antibiotics

Antimicrobial Pharmacodynamics (“activity”)

 

Bacteriostatic activity stops the organism from multiplying but does not kill it.

 

• All antimicrobials are bacteriostatic at some (low) concentrations.
• Some antimicrobials are bacteriostatic at all concentrations (tetracyclines, sulfonamides).
• Some antimicrobials are capable of bactericidal activity if

 

Bactericidal activity kills bacteria that are multiplying.

• may occur if concentrations of “cidal” antibiotics are high enough
• almost always depends on the bacteria multiplying
• the RATE and EXTENT of bactericidal activity may be:
• concentration dependent (aminoglycosides)
• concentration and time dependent (fluoroquinolones)
• time dependent (beta lactams).