AntiBacterial Drugs (ABD): Any drug that destroys bacteria or suppresses their growth
or their ability to reproduce.
Misused Terms:
AntiMicrobial, AntiBiotic & AntiBacterial Substances
- AntiMicrobial: A drug that kills or slows the spread of any type of
microbes (bacteria, virus, fungus, protozoan, … etc.).
- AntiMicrobial: A substance, produced by one microorganism,
that kills or slows the spread of another microorganism (Bacteria, virus, fungus,
protozoan, … etc.).
- AntiBacterial: A drug that kills or slows the spread of bacteria
specifically - Our topic.
Two types of
AntiBacterial Drugs:
- Bactericidal: Those which kill the bacteria - eliminate the
bacteria from the host.
- Bacteriostatic: Those which stop Bactericidal growth - limit
the bacterial burden in the body which enables the host immune system to eliminate
the bacteria.
Clinical importance: Bacteriostatic drugs are not preferred in immunocompromised patients because of a weak immune system.
Whether the drug is Bactericidal or Bacteriostatic depends
mainly on:
1. Drug Mechanism of Action (MOA):
- Drugs that interfere with the cell wall are mainly
Bactericidal.
- Drugs that interfere with the cell membrane are mainly
Bactericidal.
- Drugs that interfere with the protein synthesis, it
depends on the protein type - Major protein: Bactericidal, Minor protein:
Bacteriostatic.
- Drugs that interfere with the genetic materials are
mainly Bactericidal.
- Drugs which interfere with the metabolic pathways are
mainly Bacteriostatic.
2. Drug concentration:
- Bacteriostatic drugs may cause Bactericidal effects at high doses.
Three types of bacterial killing:
1. Concentration-dependent killing:
- As drug concentration increases, the drug effect increases.
- It's better to be given as one large dose rather than small divided doses.
- Examples: Aminoglycosides and Daptomycin.
2. Time-dependent (concentration-independent) killing:
- As the time that blood concentrations of a drug remain above the MIC increases, the drug effect increases.
- It's better to be given as small divided doses rather than one large dose.
- Examples: β-lactams, Glycopeptides, Macrolides, Clindamycin, and Linezolid.
3. Postantibiotic effect (PAE):
- The PAE is a persistent suppression of microbial growth that occurs after levels of antibiotic have fallen below the MIC.
- One dose will is sufficient.
- Examples: Aminoglycosides and Fluoroquinolones.
Clinical importance: Knowing drug's bacterial killing type helps in determination of rational dosing regimen.
Pharmacological
classification of AntiBacterial Drugs:
1. Cell Wall synthesis Inhibitors:
- Beta-Lactam Antibiotics
- Penicillins
- Cephalosporins
- Carbapenems
- Monobactams
- Beta-Lactamase Inhibitors
- Non-Beta-Lactam Antibiotics
- Glycopeptide antibiotics
- Bacitracin
- Polymyxins
- Fosfomycin
- Cycloserine
2. Cell Membrane Inhibitors:
3. Protein Synthesis Inhibitors:
- 30S ribosomal subunit
- Aminoglycosides
- Tetracyclines
- 50S ribosomal subunit
- Macrolides
- Fusidane - Not FDA approved
- Lincosamide
- Streptogramins
- Chloramphenicol
- Oxazolidinones
4. Genetic Material Inhibitors:
- Quinolones
- Fluroquinolones
5. Folate Synthesis Inhibitors:
- Dihydrofolate synthesis inhibitors
- Tetrahydrofolate synthesis inhibitors
6. Miscellaneous AntiBacterials:
- Urinary track antiseptics
- Antimycobacterial Drugs
- Drugs used in Tuberculosis
- Drugs used in Leprosy
- Not FDA approved: Are found in products not approved by the FDA but are used extensively outside the USA.
BOOKS
- Lippincott Illustrated Reviews: Pharmacology - 7th Edition
- Katzung & Trevor's Pharmacology Examination and Board Review - 12th Edition
- Basic and Clinical Pharmacology - 14th Edition
WEBSITES
GRAPHICS
Post a Comment