Drawing Pharmacology Video 5 (Antibiotics II)

[TonyPharmD]

To start off this video, Jaclyn covers the 6 different indications of vancomycin backed neatly into the acronym 'HOMES.' In our last video, we noted that vancomycin is a glycopeptide that interferes with cell wall synthesis to destroy certain types of bacteria.

Next, we march on ahead and cover more antibiotic drug classes and their respective medications

1. Altered cell membrane

• a. Daptomycin

2. Nucleic acid synthesis

• a. Fluoroquinolones
  • I. Ciprofloxacin
  • ii. Levofloxacin
  • iii. Moxifloxacin

3. Protein synthesis

• a. Aminoglycosides
  • I. Tobramycin
  • ii. Amikacin
  • iii. Gentamicin
  • IV. Streptomycin
• b. Tetracyclines
  • I. Minocycline
  • ii. Doxycycline
• c. Macrolides
  • I. Azithromycin
  • ii. Clarithromycin
  • iii. Erythromycin
• d. Lincosamide
  • I. Clindamycin
• e. Oxazolidinones
  • I. Linezolid
  • ii. Tedizolid

Cyclic lipopeptide

Daptomycin works differently than vancomycin. Instead of interfering with the bacteria's cell wall synthesis, daptomycin target's the cell membrane and creates tiny, leaky holes that eventually lead to the bacterial cell's demise. What's interesting is that even though vancomycin and daptomycin work differently, they can be used for the same indications except for one. The H in 'HOMES' stands for hospital-acquired pneumonia. Vancomycin can get in the lungs to treat this infection, but the same can't be said for daptomycin.

Fluoroquinolones (quinolones)

Instead of working on the outer portion of cells, quinolones must cross the cell membrane to exert their effect. They inhibit an enzyme called topoisomerase. This enzyme cuts bacteria's DNA so that it can be read and copied by other enzymes. Without properly working topoisomerase enzymes, bacteria cells can't replicate and the cell is eventually destroyed. All fluoroquinolones share the stem -floxacin, making them easy to recognize. Patients taking quinolones are subject to a variety of side effects, including neuropathy, tendon rupture, QTc interval prolongation. We especially worry about tendon rupture in patients concurrently taking corticosteroids, such as oral prednisone.

Protein synthesis

The next 5 drug classes disrupt bacteria's ability to create proteins. Like us, bacteria need to make proteins to survive. Inhibiting this process prevents the cells from properly replicating. These 5 drugs all work differently.

Aminoglycosides

Jaclyn talks about 4 different aminoglycosides in this video: tobramycin, amikacin, gentamicin, and streptomycin. If it helps, you can remember the acronym 'TAGS' for this drug class. Side effects are serious concerns in practice. For this reason, aminoglycosides aren't usually first-line medications.

Tetracyclines

Here we focus on minocycline and doxycycline, which share the stem -cycline. Drugs in this class all share a 4 hydrocarbon ring structure, hence tetra + cycline. Watch for the tooth discoloration side effect, prominent in children whose teeth are still growing.

Macrolides

Medications include azithromycin, clarithromycin, and erythromycin with a stem -thromycin. Just like with the fluoroquinolones, these medications can prolong the QTc interval.

Lincosamide

Watch you don't confuse clindamycin, clarithromycin, and vancomycin looking at the endings. They come from different classes.

Oxazolidinones

This drug class end in -zolid, this drug class provides a last line against some of the toughest bacteria.