Editing Azithromycin (section)

== Pharmacology ==
=== Mechanism of action ===
Azithromycin prevents [[bacterium|bacteria]] from growing by interfering with their [[protein synthesis]]. It binds to the 50S subunit of the bacterial [[ribosome]], thus inhibiting [[translation (biology)|translation]] of [[mRNA]]. Nucleic acid synthesis is not affected.<ref name="Zithromax FDA label" />

=== Pharmacokinetics ===
Azithromycin is an acid-stable antibiotic, so it can be taken orally with no need of protection from gastric acids. It is readily absorbed, but absorption is greater on an empty stomach. Time to peak concentration (T<sub>max</sub>) in adults is 2.1 to 3.2 hours for oral dosage forms. Due to its high concentration in [[phagocytes]], azithromycin is actively transported to the site of infection. During active phagocytosis, large concentrations are released. The concentration of azithromycin in the tissues can be over 50 times higher than in plasma due to [[ion trapping]] and its high lipid solubility.<ref>{{cite journal | url=http://doi.org/10.1002/bmc.2898 | doi=10.1002/bmc.2898 | title=A concise review of HPLC, LC-MS and LC-MS/MS methods for determination of azithromycin in various biological matrices | date=2013 | journal=Biomedical Chromatography | volume=27 | issue=10 | pages=1243–1258 | pmid=23553351 | vauthors=Sharma K, Mullangi R | access-date=16 February 2024 | archive-date=8 March 2024 | archive-url=https://web.archive.org/web/20240308023320/https://analyticalsciencejournals.onlinelibrary.wiley.com/doi/10.1002/bmc.2898 | url-status=live | url-access=subscription }}</ref><ref name="pmid32389720">{{cite journal |vauthors=Derendorf H |title=Excessive lysosomal ion-trapping of hydroxychloroquine and azithromycin |journal=Int J Antimicrob Agents |volume=55 |issue=6 |pages=106007 |date=June 2020 |pmid=32389720 |pmc=7204663 |doi=10.1016/j.ijantimicag.2020.106007 }}</ref> Azithromycin's half-life allows a large single dose to be administered and yet maintain bacteriostatic levels in the infected tissue for several days.<ref name="Zithromax FDA label" />

Following a single dose of 500&nbsp;mg, the apparent terminal elimination half-life of azithromycin is 68 hours.<ref name="Zithromax FDA label" /> [[bilirubin|Biliary]] excretion of azithromycin, predominantly unchanged, is a major route of elimination.<ref>{{cite journal | doi=10.5402/2012/859473 | doi-access = free | title-link = doi | title=Application of Different Analytical Techniques and Microbiological Assays for the Analysis of Macrolide Antibiotics from Pharmaceutical Dosage Forms and Biological Matrices | date=2012 | journal=ISRN Analytical Chemistry | volume=2012 | pages=1–17 | vauthors = Bekele LK, Gebeyehu GG }}</ref> Over the course of a week, about 6% of the administered dose appears as an unchanged drug in [[urine]].<ref name="Zithromax FDA label" />