Azithromycin, sold under the brand names Zithromax (in oral form) and Azasite (as an eye drop), is an antibiotic medication used for the treatment of several bacterial infections.

[10][13] Azithromycin was discovered in Yugoslavia (present day Croatia) in 1980 by the pharmaceutical company Pliva and approved for medical use in 1988.

It was reported that because only low levels are found in breast milk and the medication has also been used in young children, it is unlikely that breastfed infants would have adverse effects.

In adults with severe asthma, low-dose azithromycin may be prescribed as an add-on treatment when standard therapies such as inhaled corticosteroids or long-acting beta2-agonists are not sufficient.

The richness (diversity) of the lung microbiome has been identified as a key factor in determining the effectiveness of azithromycin treatment.

Long-term use of azithromycin reduces the presence of H. influenzae bacteria in the airways but also increases resistance against macrolide antibiotics.

Clarithromycin and erythromycin have a 14-membered lactone ring, which is more prone to demethylation by CYP3A4 and subsequent formation of nitrosoalkenes, the reactive metabolites that cause mechanism-based inhibition.

By inhibiting CYP3A4, macrolide antibitiotics, such as erythromycin and clarithromycin, but not azithromycin, can significantly increase the AUC of the drugs that depend on it for clearance, which can lead to higher risk of adverse effects or drug-drug interactions.

Co-administration of clarithromycin or erythromycin with statins can increase the risk of statin-induced myopathy, a condition that causes muscle pain and damage.

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.

[50][51] Azithromycin's half-life allows a large single dose to be administered and yet maintain bacteriostatic levels in the infected tissue for several days.

[8] A team of researchers at the pharmaceutical company Pliva in Zagreb, former Yugoslavia (present day Croatia) discovered azithromycin in 1980.

[19][20] It is sold under many brand names worldwide including 3-Micina, A Sai Qi, Abacten, Abbott, Acex, Acithroc, Actazith, Agitro, Ai Mi Qi, Amixef, Amizin, Amovin, An Mei Qin, Ao Li Ping, Apotex, Lebanon, Aratro, Aruzilina, Arzomicin, Arzomidol, Asizith, Asomin, Astidal, Astro, Athofix, Athxin, Atizor, Atromizin, Avalon, AZ, AZA, Azacid, Azadose, Azalid, Azalide, AzaSite, Azaroth, Azath, Azatril, Azatril, Azax, Azee, Azeecor, Azeeta, Azelide, Azeltin, Azenil, Azeptin, Azerkym, Azi, Aziact, Azibact, Azibactron, Azibay, Azibect, Azibest, Azibiot, Azibiotic, Azicare, Azicin, Azicine, Aziclass, Azicom, Azicure, Azid, Azidose, Azidraw, Azifam, Azifarm, Azifast, Azifine, Aziflax, Azigen, Azigram, Azigreat, Azikare, Azilide, Azilife, Azilip, Azilup, Azimac, Azimax, Azimed, Azimepha, Azimex, Azimit, Azimix, Azimon, Azimore, Azimycin, Azimycine, Azin, Azindamon, Azinew, Azinex, Azinif, Azinil, Azintra, Aziom, Azipar, Aziped, Aziphar, Azipin, Aziplex, Azipro, Aziprome, Aziquilab, Azirace, Aziram, Aziresp, Aziride, Azirol, Azirom, Azirox, Azirute, Azirutec, Aziset, Azisis, Azison, Azissel, Aziswift, Azit, Azita, Azitam, Azitex, Azith, Azithral, Azithrin, Azithro, Azithrobeta, Azithrocin, Azithrocine, Azithromax, Azithromed, Azithromicina, Azithromycin, Azithromycine, Azithromycinum, Azithrovid, Azitic, Azitive, Azitome, Azitrac, Azitral, Azitrax, Azitredil, Azitrex, Azitrim, Azitrin, Azitrix, Azitro, Azitrobac, Azitrocin, Azitroerre, Azitrogal, Azitrolabsa, Azitrolid, Azitrolit, Azitrom, Azitromac, Azitromax, Azitromek, Azitromicin, Azitromicina, Azitromycin, Azitromycine, Azitrona, Azitropharma, Azitroteg, Azitrox, Azitsa, Azitus, Azivar, Azivirus, Aziwill, Aziwok, Azix, Azizox, Azmycin, Azo, Azobat, Azocin, Azoget, Azoheim, Azoksin, Azom, Azomac, Azomax, Azomex, Azomycin, Azomyne, Azores, Azorox, Azostar, Azot, Azoxin, Azras, Azro, Azrocin, Azrolid, Azromax, Azroplax, Azrosin, Aztin, Aztrin, Aztro, Aztrogecin, Azvig, Azycin, Azycyna, Azydrop, Azypin, Azytact, Azytan, Azyter, Azyter, Azyth, Azywell, Azza, Ba Qi, Bactaway, Bactizith, Bactrazol, Bai Ke De Rui, Batif, Bazyt, Bezanin, Bin Qi, Binozyt, BinQi, Biocine, Biozit, Bo Kang, Canbiox, Cetaxim, Charyn, Chen Yu, Cinalid, Cinetrin, Clamelle, Clearsing, Corzi, Cozith, Cronopen, Curazith, Delzosin, Demquin, Dentazit, Disithrom, Doromax, Doyle, Elzithro, Eniz, Epica, Ethrimax, Ezith, Fabodrox, Fabramicina, Feng Da Qi, Figothrom, Floctil, Flumax, Fu Qi-Hua Yuan, Fu Rui Xin, Fuqixing, Fuxin-Hai Xin Pharm, Geozif, Geozit, Gitro, Goldamycin, Gramac, Gramokil, Hemomicin, Hemomycin, I-Thro, Ilozin, Imexa, Inedol, Infectomycin, Iramicina, Itha, Jin Nuo, Jin Pai Qi, Jinbo, Jun Jie, Jun Wei Qing, Kai Qi, Kang Li Jian, Kang Qi, Katrozax, Ke Lin Da, Ke Yan Li, Koptin, Kuai Yu, L-Thro, Laz, Legar, Lg-Thral, Li Ke Si, Li Li Xing, Li Qi, Li Quan Yu, Lin Bi, Lipuqi, Lipuxin, Lizhu Qile, Loromycin, Lu Jia Kang, Luo Bei Er, Luo Qi, Maazi, Macroazi, Macromax, Macrozit, Maczith, Makromicin, Maxmor, Mazit, Mazitrom, Medimacrol, Meithromax, Mezatrin, Ming Qi Xin, Misultina, Mycinplus, Na Qi, Nadymax, Naxocina, Neblic, Nemezid, Neofarmiz, Nifostin, Nobaxin, Nokar, Novatrex, Novozithron, Novozitron, Nurox, Odaz, Odazyth, Onzet, Oranex, Oranex, Ordipha, Orobiotic, Pai Fen, Pai Fu, Paiqi, Pediazith, Pi Nis, Portex, Pu He, Pu Le Qi, Pu Yang, Qi Gu Mei, Qi Mai Xing, Qi Nuo, Qi Tai, Qi Xian, Qili, Qiyue, Rarpezit, Razimax, Razithro, Rezan, Ribotrex, Ribozith, Ricilina, Rizcin, Romax, Romycin, Rothin (Rakaposhi), Rozalid, Rozith, Ru Shuang Qi, Rui Qi, Rui Qi Lin, Rulide, Sai Jin Sha, Sai Le Xin, Sai Qi, Santroma, Selimax, Sheng Nuo Ling, Shu Luo Kang, Simpli-3, Sisocin, Sitrox, Sohomac, Stromac, Su Shuang, Sumamed, Sumamox, Tailite, Talcilina, Tanezox, Te Li Xin, Tetris, Texis, Thoraxx, Throin, Thromaxin, Tong Tai Qi Li, Topt, Toraseptol, Tremac, Trex, Tri Azit, Triamid, Tridosil, Trimelin, Tritab, Tromiatlas, Tromix, Trozamil, Trozin, Trozocina, Trulimax, Tuoqi, Udox, Ultreon, Ultreon, Vectocilina, Vinzam, Visag, Vizicin, Wei Li Qinga, Wei Lu De, Wei Zong, Weihong, Xerexomair, Xi Le Xin, Xi Mei, Xin Da Kang, Xin Pu Rui, Xithrone, Ya Rui, Yan Sha, Yanic, Yi Nuo Da, Yi Song, Yi Xina, Yin Pei Kang, Yong Qi, You Ni Ke, Yu Qi, Z-3, Z-PAK, Zady, Zaiqi, Zaret, Zarom, Zathrin, Zedbac, Zeelide, Zeemide, Zenith, Zentavion, Zetamac, Zetamax, Zeto, Zetron, Zevlen, Zibramax, Zicho, Zigilex, Zikrax, Zikti, Zimacrol, Zimax, Zimicina, Zimicine, Zindel, Zinfect, Zirom, Zisrocin, Zistic, Zit-Od, Zitab, Zitax, Zithrax, Zithrin, Zithro-Due, Zithrobest, Zithrodose, Zithrogen, Zithrokan, Zithrolide, Zithromax, Zithrome, Zithromed, Zithroplus, Zithrotel, Zithrox, Zithroxyn, Zithtec, Zitinn, Zitmac, Zitraval, Zitrax, Zitrex, Zitric, Zitrim, Zitrobid, Zitrobiotic, Zithrolect, Zitrocin, Zitrogram, Zitrolab, Zitromax, Zitroneo, Zitrotek, Ziyoazi, Zmax, Zocin, Zomax, Zotax, Zycin, and Zythrocin.

[1] It is sold as a combination drug with cefixime as Anex-AZ, Azifine-C, Aziter-C, Brutacef-AZ, Cezee, Fixicom-AZ, Emtax-AZ, Olcefone-AZ, Starfix-AZ, Zeph-AZ, Zicin-CX, and Zifi-AZ.

These effects are believed to be due to azithromycin's ability to suppress a transcription factor called nuclear factor-kappa B (NF-κB) resulting in blockade of inflammatory response pathways downstream from NF-κB activation leading to decreased chemokine receptor CXCR4 signaling causing reduced inflammation.

[66] Inflammation in rosacea is thought to be associated with increased production of reactive oxygen species (ROS) by inflammatory cells.

[67][68][69][70][71] Despite early evidence showing azithromycin slowed down coronavirus multiplication in laboratory settings, further research indicates it to be ineffective as a treatment for COVID-19 in humans.

[72] Azithromycin in conjunction with chloroquine or hydroxychloroquine has been associated with deleterious outcomes in COVID-19 patients, including drug-induced QT prolongation.

[73] After a large-scale trial showed no benefit of using azithromycin in treating COVID-19, the UK's National Institute for Health and Care Excellence (NICE) updated its guidance and no longer recommends the medication for COVID-19.

[74][75] Azithromycin has been studied in the treatment of chronic fatigue syndrome (CFS) and has been reported to improve or even resolve symptoms in some cases.

[81][82] The potential role of azithromycin in inhibiting the autophagic destruction of non-tuberculous mycobacteria (NTM) within macrophages has garnered significant attention.

This mechanism may contribute to the observed correlation between long-term macrolide monotherapy and an increased risk of NTM infection and the emergence of macrolide-resistant strains.

[83] Azithromycin has been shown to be an effective preventive measure against many postpartum infections in mothers following planned vaginal births; still, its impact on neonatal outcomes remains inconclusive and is the subject of ongoing research.