Antibacterial trends

Hydrophilic

Aminopenicilins → all Beta lactams [+ Glycopeptides]

Aminoglycosides

Tetracyclin - always intermediate (besides bioavailability)

Lipophilic (all others/majority)

• tetracyclins = intermediate

If lipophilic → easily absorbed by gut → good oral bioavailability

Aminoglycosides → very hydrophilic = NO oral Bio

vs penicillins = just poor

2 Exceptions

• Aminopenicilins → hydrophilic but good oral bioavailability

• Tetracyclins → good oral bioavailabilty (here not intermdediate)

Plasma protein binding

Lipophilic drug → bind strongly to plasma proteins → cannot be in solution

Phenicols, Trimethoprims, Sulphonamides - not amazing but good

4 Exceptions

• Beta lactams → extremely variable plasma protein binding

• Macrolides & lincosamides→ also extremely variable

• Quinolones → lipophilic BUT low binding

• Nitroimidazoles → lipophilic but low binding

Volume of distribution

• no exceptions

2 REACH Brain

• Phenicols

• Quinolones

Lipophilic → high Vd → can travel inside cells

Hydrophilic → low Vd → transporter to enter cells

Excretion/Metabolism

Lipophilic → Hepatic

Hydrophilic → Renal

3 Exceptions

Quinolones - BOTH
Tetracyclines - BOTH (intermediate)

Sulphonamides → lipophilic but completely renal

Narrow Spectrums [4]

1. Glycopeptides (gram +ve)

2. Lincosamides & Macrolides (gram +ve)

3. Metranidazoles (anaerobes)

4. Amino-glycosides - narrow spectrum (Gram -ve and some staph)

Acidic

Beta lactams

Sulphonamides

Nitroimidazoles

Basic

Quinolones

Aminoglycosides

Trimethoprim

Macrolides and lincosamides

pH exceptions (either acidic nor basic)

phenicols → completely uncharged

tetracyclines → amphoteric - zwiterone

Concentration dependent

• Quinolones

• Aminoglycoside

• Metranidazoles

Time dependent

• beta lactams

• phenicols

• S&T

• macrolides and lincosamides

Both time and conc dependent

Tetracyclin

Vancomycin = Glycopeptides