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Azithromycin

Generic Name
Azithromycin
Brand Names
Azasite, Zithromax, Zmax
Drug Type
Small Molecule
Chemical Formula
C38H72N2O12
CAS Number
83905-01-5
Unique Ingredient Identifier
J2KLZ20U1M

Overview

Azithromycin is a broad-spectrum macrolide antibiotic with a long half-life and a high degree of tissue penetration . It was initially approved by the FDA in 1991 . It is primarily used for the treatment of respiratory, enteric and genitourinary infections and may be used instead of other macrolides for some sexually transmitted and enteric infections. It is structurally related to erythromycin . Azithromycin [9-deoxo-9a-aza-9a-methyl-9a-homoerythromycin] is a part of the azalide subclass of macrolides, and contains a 15-membered ring, with a methyl-substituted nitrogen instead of a carbonyl group at the 9a position on the aglycone ring, which allows for the prevention of its metabolism. This differentiates azithromycin from other types of macrolides . In March 2020, a small study was funded by the French government to investigate the treatment of COVID-19 with a combination of azithromycin and the anti-malaria drug hydroxychloroquine. The results were positive, all patients taking the combination were virologically cured within 6 days of treatment, however, larger studies are required.

Indication

Azithromycin should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria in order to prevent the development antimicrobial resistance and maintain the efficacy of azithromycin . Azithromycin is indicated for the treatment of patients with mild to moderate infections caused by susceptible strains of the microorganisms listed in the specific conditions below. Recommended dosages, duration of therapy and considerations for various patient populations may vary among these infections. Refer to the FDA label and "Indications" section of this drug entry for detailed information . Adults: Acute bacterial exacerbations of chronic obstructive pulmonary disease due to Haemophilus influenzae, Moraxella catarrhalis or Streptococcus pneumoniae Acute bacterial sinusitis due to Haemophilus influenzae, Moraxella catarrhalis or Streptococcus pneumoniae Community-acquired pneumonia due to Chlamydophila pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae or Streptococcus pneumoniae in patients appropriate for oral therapy Pharyngitis/tonsillitis caused by Streptococcus pyogenes as an alternative to first-line therapy in individuals who cannot use first-line therapy. Uncomplicated skin and skin structure infections due to Staphylococcus aureus, Streptococcus pyogenes, or Streptococcus agalactiae. Abscesses usually require surgical drainage. Urethritis and cervicitis due to Chlamydia trachomatis or Neisseria gonorrhoeae. Genital ulcer disease in men due to Haemophilus ducreyi (chancroid). Due to the small number of women included in clinical trials, the efficacy of azithromycin in the treatment of chancroid in women has not been established. Pediatric Patients Acute otitis media caused by Haemophilus influenzae, Moraxella catarrhalis or Streptococcus pneumoniae Community-acquired pneumonia due to Chlamydophila pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae or Streptococcus pneumoniae in patients appropriate for oral therapy. Pharyngitis/tonsillitis caused by Streptococcus pyogenes as an alternative to first-line therapy in individuals who cannot use first-line therapy.

Associated Conditions

  • Acute Bacterial Sinusitis (ABS)
  • Acute Otitis Media (AOM)
  • Acute bacterial exacerbation of COPD caused by Haemophilus Influenza Infections, Moraxella Catarrhalis Infection, Streptococcus Pneumoniae Infections
  • Bacterial Conjunctivitis
  • Bacterial Sinusitis
  • Cervicitis
  • Chancroid
  • Community Acquired Pneumonia (CAP)
  • Genital Ulcer Disease (GUD)
  • Pelvic Inflammatory Disease (PID)
  • Pharyngitis
  • Streptococcal Pharyngitis
  • Tonsillitis bacterial
  • Tonsillitis streptococcal
  • Traveler's Diarrhea
  • Uncomplicated Skin and Skin Structure Infections
  • Urethritis

Research Report

Published: Jul 14, 2025

Azithromycin (DB00207): A Comprehensive Monograph on its Pharmacology, Clinical Utility, and Safety Profile

Executive Summary

Azithromycin is a semi-synthetic, second-generation macrolide antibiotic belonging to the azalide subclass, distinguished by a 15-membered macrocyclic lactone ring. Since its discovery in 1980 and subsequent US FDA approval in 1991, it has become one of the most widely prescribed antibiotics globally, valued for its broad spectrum of activity, unique pharmacokinetic profile, and convenient dosing regimens.[1] Its mechanism of action involves the inhibition of bacterial protein synthesis via binding to the 50S ribosomal subunit, effectively halting bacterial growth.[1] Beyond this primary antibacterial effect, azithromycin exhibits significant immunomodulatory and anti-inflammatory properties, which contribute to its efficacy in chronic inflammatory airway diseases.[2]

The drug's defining characteristic is its pharmacokinetic profile, marked by rapid absorption, extensive tissue distribution, and profound intracellular accumulation, particularly within phagocytic cells. This "ion-trapping" phenomenon, coupled with a long terminal elimination half-life of approximately 68 hours, allows for short-course therapeutic regimens (e.g., 3-5 days) that maintain effective drug concentrations at the site of infection for a prolonged period.[5] This profile, combined with minimal interaction with the cytochrome P450 system, distinguishes it from older macrolides like erythromycin.[7]

Continue reading the full research report

Clinical Trials

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Title
Posted
Study ID
Phase
Status
Sponsor
2013/10/07
Phase 3
Completed
Lihir Medical Centre
2013/08/13
Phase 2
Completed
2013/08/09
Phase 2
Terminated
2013/08/02
Phase 4
Completed
2013/07/19
Phase 4
Withdrawn
2013/04/05
Phase 3
Completed
Anna Griffiths, MRC
2013/04/05
Phase 4
Completed
2013/03/28
Phase 4
UNKNOWN
University of Roma La Sapienza
2013/02/28
Phase 3
Completed
2013/02/22
Phase 2
Withdrawn
Philadelphia Eye Associates

FDA Drug Approvals

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Approved Product
Manufacturer
NDC Code
Route
Strength
Effective Date
NuCare Pharmaceuticals, Inc.
68071-3169
ORAL
500 mg in 1 1
2/11/2021
NuCare Pharmaceuticals,Inc,
68071-2963
ORAL
900 mg in 22.5 mL
3/21/2023
Asclemed USA, Inc.
76420-589
ORAL
500 mg in 1 1
9/1/2023
Quality Care Products, LLC
55700-859
ORAL
250 mg in 1 1
4/11/2023
Alembic Pharmaceuticals Limited
46708-058
ORAL
500 mg in 1 1
1/13/2023
Alembic Pharmaceuticals Limited
46708-253
ORAL
600 mg in 1 1
1/27/2023
MedVantx, Inc.
66116-524
ORAL
200 mg in 5 mL
5/16/2013
Wockhardt USA LLC.
64679-961
ORAL
250 mg in 1 1
12/8/2021
Asclemed USA, Inc.
76420-213
ORAL
250 mg in 1 1
3/7/2022
ACI Healthcare USA, Inc.
71093-175
ORAL
500 mg in 1 1
12/4/2023

EMA Drug Approvals

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Authorization Holder
Status
Issued Date
No EMA approvals found for this drug.

HSA Drug Approvals

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Approval Number
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Approval Date
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NMPA Drug Approvals

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Approved Product
Company
Approval Number
Drug Type
Dosage Form
Approval Date
Azithromycin for Injection
国药准字H20074176
化学药品
注射剂
7/16/2022
Azithromycin for Injection
国药准字H19990389
化学药品
注射剂
4/2/2020
Azithromycin for Injection
国药准字H20237135
化学药品
注射剂
10/27/2023
Azithromycin for Injection
国药准字H20243582
化学药品
注射剂
4/24/2024
Azithromycin for Injection
国药准字H20020269
化学药品
注射剂
9/8/2020
Azithromycin for Injection
国药准字H20063284
化学药品
注射剂
9/9/2020
Azithromycin for Injection
国药准字H20000197
化学药品
注射剂(冻干)
7/13/2020
Azithromycin for Injection
国药准字H20254211
化学药品
注射剂
5/20/2025
Azithromycin for Injection
国药准字H20066777
化学药品
注射剂(冻干粉针剂)
7/15/2020
Azithromycin for Injection
国药准字H20066778
化学药品
注射剂(冻干粉针剂)
7/15/2020

PPB Drug Approvals

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Company
Licence No.
Strength
Registration Date
No PPB approvals found for this drug.

TGA Drug Approvals

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ARTG ID
Sponsor
Registration Type
Status
Registration Date
No TGA approvals found for this drug.

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