Azithromycin

Azithromycin also known by the brand name Zithromax is a macrolide, broad-spectrum antibacterial that inhibits bacterial protein synthesis, quorum-sensing and reduces the formation of biofilm. Macroslides are a class of drugs that possess a macrocyclic lactone ring of 12 or more elements. Independent of their antimicrobial properties, azithromycin and other macroslides have immunomodulatory effects.

Azithromycin is a semi-synthetic derivative of erythromycin. Azithromycin accumulates in phagocytes at sites of inflammation and to a less and varying extent in other cells such as epithelial cells, fibroblasts, lymphocytes and hepatocytes.

Azithromycin is indicated for bacterial infections of respiratory, urogenital, dermal and other areas of the body. Pneumococcal macrolide resistance is linked to increased clinical use of macrolide antibiotics.

The drug has immunomodulatory effects in chronic inflammatory disorders such as diffuse panbronchiolitis, post-transplant bronchiolitis and rosacea. Azithromycin modulates host immune response with long-term therapeutic benefit in cystic fibrosis, non-cystic fibrosis bronchiectasis, exacerbations of chronic obstructive pulmonary disease (COPD) and non-eosinophilic asthma. Azithromycin has stimulatory effects on immune and epithelial cells through interactions with phospholipids and Erk1/2 which may promote host defense. The drug later modulates transcription factors AP-1, NFkB, inflammatory cytokine and mucin release which may reduce bystander tissue injury and resolve inflammation.

Hydroxychloroquine a chloroquine derivative, given alone and in combination with the the antibiotic azithromycin (aka Zithromas or Azithrocin) has shown early evidence of being effective in treating COVID-19 in preliminary results in a small study on 30 patients in France. Azithromycin was given to some patients to prevent bacterial super-infection and the combination therapy appeared to be more effective than hydroxychloroquine alone. It is not clear if differences between patients that received hydroxychoroquine alone and the combination therapy may be due to differences in the patient's viral load between the two groups. In March 2020 the FDA cleared New York sites to use hydroxychloroquine and Zithromax (azithromycin) together as treatment for COVID-19 in clinical trials.