Drug Actions

Antimicrobial Drugs
Introduction	Drug Actions	Antibacterial Antibiotics: Cell Wall Synthesis Inhibitors	Protein Synthesis Inhibitors	Plasma Membrane Injury DNA/RNA Synthesis Inhibitors

Antifungal Drugs	Antiviral Drugs	Antiprotozoan And Antihelminthic Drugs	Tests To Guide Chemotherapy	Effectiveness Of Chemotherapeutic Agents

8. Define and differentiate between bactericidal and bacteriostatic drugs.
9. List the specific modes of action of antimicrobial drugs.

General action is either by directly killing microorganisms (bactericidal) or by inhibiting their growth (bacteriostatic).

Some agents, such as penicillin, inhibit cell wall synthesis in bacteria.

This of course requires that the bacteria are actively growing.
Since human cells do not have peptidoglycan cell walls penicillin has low toxicity; the primary concern is for allergy, which only occurs in a low percentage of the population, making penicillin the antibiotic with the fewest side effects.

Other agents, such as chloramphenicol, erythromycin, tetracyclines, and streptomycin, inhibit protein synthesis by acting on 70s ribosomes.

Agents such as polymyxin B cause injury to plasma membranes.

Rifampin and quinolones inhibit nucleic acid synthesis.

Agents such as sulfanilamide act as antimetabolites by competitively inhibiting enzyme activity.

Inhibition of Protein Synthesis

Injury to Plasma Membrane

Introduction	Drug Actions	Antibacterial Antibiotics: Cell Wall Synthesis Inhibitors	Protein Synthesis Inhibitors	Plasma Membrane Injury DNA/RNA Synthesis Inhibitors

Antifungal Drugs	Antiviral Drugs	Antiprotozoan And Antihelminthic Drugs	Tests To Guide Chemotherapy	Effectiveness Of Chemotherapeutic Agents