Drug Cards Daily

Episode #35: azithromycin (Zithromax) | Podcast Show Notes
azithromycin (az ith roe MYE sin)

Below will be links for the full Podcast and the Drug Card for azithromycin along with a brief summary of various points on azithromycin. 

QUESTIONS:

  1. True or False: Azithromycin is a penicillin based antibiotic. 
  2. Describe the mechanism of action behind azithromycin.
  3. Zithromax has high penetration into which of the following. Select all that apply. 
    • A). Skin
    • B). Lungs
    • C). Sputum
    • D). Spinal Fluid
    • E). Cervix
  4. Which dosing regimens are the most correct? Select all that apply.
    • A). Tablets: 500 mg po on day 1, then 250 mg bid on days 2-5.
    • B). Tablets: 250 mg po bid on day 1, then 250 mg tid on days 2-5.
    • C). Tablets: 1000 mg po for one dose.
    • D). Suspension: 250 mg po bid for 14 days.
    • E). Suspension: 250 mg po bid for 10 days.

SUMMARY:

Azithromycin is a macrolide antibiotic used to treat many bacterial infections. Some common uses are for Community Acquired Pneumonia (CAP), Group A Strep, Acute Exacerbations of COPD, STDs, among other bacterial infections. One of the most commonly known dosing regimens is 500 mg on day one, then 250 mg on days 2-5. When using the reconstituted suspension it must be refrigerated once reconstituted it must be discarded after 10 days. Azithromycin works through the inhibition of RNA-dependent protein synthesis by binding to the 50S ribosomal subunit. By blocking transpeptidation this inhibits the chain elongation step of protein synthesis. Azithromycin distributes well into most tissues and fluids with the exception of cerebrospinal fluid (CSF). Protein binding is concentration dependent varying from 7-51%. Azithromycin can be taken with or without food but food may decrease any GI distress.

ANSWERS:  

  1. False. Azithromycin is a macrolide and not penicillin based. 
  2. Azithromycin works through the inhibition of RNA-dependent protein synthesis by binding to the 50S ribosomal subunit. By blocking transpeptidation this inhibits the chain elongation step of protein synthesis.
  3. A, B, C and E. D is incorrect due to poor CSF penetration.
  4. A, C, and E are the most correct. B is incorrect because the day 1 dose is not split and the subsequent doses are not tid. D is incorrect because the suspension should be discarded after 10 days.
Did you get any wrong? Make sure to listen to this week’s episode and download the free Drug Card for azithromycin.

PDF of Drug Card: azithromycin