Is Azithromycin safe for dogs and cats?
Low risk for petsAzithromycin is used off-label in veterinary medicine for small animal respiratory infections, Bartonella infections, Toxoplasma, and Cryptosporidium in dogs; its long tissue half-life and once-daily dosing are practical advantages in veterinary use. Veterinary dosing (dogs): 5–10 mg/kg once daily or every other day; tissue concentrations well above MIC are achieved with this schedule. Safety in dogs: generally well-tolerated; GI effects (vomiting, diarrhea) are the most common adverse effects; cardiac QT prolongation in dogs has less clinical documentation than in humans. Bartonella treatment: azithromycin is used for Bartonella henselae (cat scratch disease) and related infections in dogs; efficacy data are supportive but limited. Prophylaxis for immunocompromised dogs: MAC (Mycobacterium avium complex) prophylaxis with azithromycin or clarithromycin in dogs undergoing immunosuppressive therapy is occasionally employed, mirroring human HIV-related MAC prophylaxis practice. Resistance: increasing macrolide resistance in canine respiratory and skin pathogens mirrors the human situation; azithromycin should not be used empirically for Staphylococcus pseudintermedius skin infections where susceptibility testing is feasible.
What is azithromycin?
The IUPAC name is (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-11-[(2S,3R,4S,6R)-4-(dimethylamino)-3-hydroxy-6-methyloxan-2-yl]oxy-2-ethyl-3,4,10-trihydroxy-13-[(2R,4R,5S,6S)-5-hydroxy-4-methoxy-4,6-dimethyloxan-2-yl]oxy-3,5,6,8,10,12,14-heptamethyl-1-oxa-6-azacyclopentadecan-15-one.
Also known as: (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-11-[(2S,3R,4S,6R)-4-(dimethylamino)-3-hydroxy-6-methyloxan-2-yl]oxy-2-ethyl-3,4,10-trihydroxy-13-[(2R,4R,5S,6S)-5-hydroxy-4-methoxy-4,6-dimethyloxan-2-yl]oxy-3,5,6,8,10,12,14-heptamethyl-1-oxa-6-azacyclopentadecan-15-one, Zithromax, Hemomycin, Azithromycine.
- IUPAC name
- (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-11-[(2S,3R,4S,6R)-4-(dimethylamino)-3-hydroxy-6-methyloxan-2-yl]oxy-2-ethyl-3,4,10-trihydroxy-13-[(2R,4R,5S,6S)-5-hydroxy-4-methoxy-4,6-dimethyloxan-2-yl]oxy-3,5,6,8,10,12,14-heptamethyl-1-oxa-6-azacyclopentadecan-15-one
- CAS number
- 83905-01-5
- Molecular formula
- C38H72N2O12
- Molecular weight
- 749.0 g/mol
- SMILES
- CCC1C(C(C(N(CC(CC(C(C(C(C(C(=O)O1)C)OC2CC(C(C(O2)C)O)(C)OC)C)OC3C(C(CC(O3)C)N(C)C)O)(C)O)C)C)C)O)(C)O
- PubChem CID
- 447043
Risk for dogs
Low riskAzithromycin is used off-label in veterinary medicine for small animal respiratory infections, Bartonella infections, Toxoplasma, and Cryptosporidium in dogs; its long tissue half-life and once-daily dosing are practical advantages in veterinary use. Veterinary dosing (dogs): 5–10 mg/kg once daily or every other day; tissue concentrations well above MIC are achieved with this schedule. Safety in dogs: generally well-tolerated; GI effects (vomiting, diarrhea) are the most common adverse effects; cardiac QT prolongation in dogs has less clinical documentation than in humans. Bartonella treatment: azithromycin is used for Bartonella henselae (cat scratch disease) and related infections in dogs; efficacy data are supportive but limited. Prophylaxis for immunocompromised dogs: MAC (Mycobacterium avium complex) prophylaxis with azithromycin or clarithromycin in dogs undergoing immunosuppressive therapy is occasionally employed, mirroring human HIV-related MAC prophylaxis practice. Resistance: increasing macrolide resistance in canine respiratory and skin pathogens mirrors the human situation; azithromycin should not be used empirically for Staphylococcus pseudintermedius skin infections where susceptibility testing is feasible.
Regulatory consensus
3 regulatory and scientific bodies have classified Azithromycin. The classifications differ — that's the data.
| Agency | Year | Classification | Notes |
|---|---|---|---|
| FDA | — | Approved for community-acquired pneumonia (CAP), acute bacterial exacerbations of COPD, acute bacterial sinusitis, pharyngitis/tonsillitis, skin/soft tissue infections, urethritis/cervicitis (chlamydia), and Mycobacterium avium complex (MAC) prophylaxis/treatment | Indication-specific FDA approval |
| FDA | 2013 | QT prolongation warning | FDA Safety Communication warned of risk of torsades de pointes and sudden cardiac death |
| WHO | — | Watch | WHO antibiotic classification due to overuse and resistance development |
Regulators apply different standards of evidence — animal-data weighting, exposure-pattern assumptions, epidemiological power thresholds — which is why two scientific bodies can review the same data and reach different conclusions. The disagreement is the data.
Where pets encounter azithromycin
- Industrial Facilities — Manufacturing plants, Chemical storage areas, Waste treatment sites
- Occupational Environments — Factories, Warehouses, Transportation vehicles
Safer alternatives
Lower-risk approaches that achieve a similar outcome to Azithromycin:
-
Therapeutic alternatives (consult prescriber)
Trade-offs: Drug-specific. Cannot substitute without medical guidance.Relative cost: 1.2-2×
Frequently asked questions
Is azithromycin safe for pets?
Azithromycin is used off-label in veterinary medicine for small animal respiratory infections, Bartonella infections, Toxoplasma, and Cryptosporidium in dogs; its long tissue half-life and once-daily dosing are practical advantages in veterinary use. Veterinary dosing (dogs): 5–10 mg/kg once daily or every other day; tissue concentrations well above MIC are achieved with this schedule. Safety in dogs: generally well-tolerated; GI effects (vomiting, diarrhea) are the most common adverse effects; cardiac QT prolongation in dogs has less clinical documentation than in humans. Bartonella treatment: azithromycin is used for Bartonella henselae (cat scratch disease) and related infections in dogs; efficacy data are supportive but limited. Prophylaxis for immunocompromised dogs: MAC (Mycobacterium avium complex) prophylaxis with azithromycin or clarithromycin in dogs undergoing immunosuppressive therapy is occasionally employed, mirroring human HIV-related MAC prophylaxis practice. Resistance: increasing macrolide resistance in canine respiratory and skin pathogens mirrors the human situation; azithromycin should not be used empirically for Staphylococcus pseudintermedius skin infections where susceptibility testing is feasible.
What products contain azithromycin?
Azithromycin appears in: Manufacturing plants (Industrial facilities); Chemical storage areas (Industrial facilities); Factories (Occupational environments); Warehouses (Occupational environments).
Why do regulators disagree about azithromycin?
Azithromycin has been classified by 3 agencies including FDA, FDA, WHO, with differing conclusions. Regulators apply different standards of evidence (animal data weighting, exposure-pattern assumptions, epidemiological power thresholds), which is why two scientific bodies can review the same data and reach different conclusions. See the regulatory consensus table on this page for the full picture.
See Azithromycin in the pets app
Look up products containing azithromycin, compare to alternatives, and explore the full data record.
Open in pets View raw API dataSources (2)
- FDA Prescribing Information: Azithromycin (Zithromax) — macrolide/azalide; QT prolongation Black Box; 2013 cardiac safety communication; neonatal pyloric stenosis; long tissue half-life; Z-pack; Watch category; COVID-19 no benefit (2023) (2023) — regulatory
- WHO AWaRe Classification of Antibiotics — Access/Watch/Reserve categories; stewardship framework; amoxicillin Access category; ciprofloxacin/azithromycin Watch; vancomycin Reserve; resistance drivers; outpatient prescribing guidance (2023) (2023) — regulatory
Reference data, not professional advice. Aggregates publicly available regulatory and scientific data; not a substitute for veterinary, medical, legal, or regulatory advice. Why we built ALETHEIA →