Azithromycin (brand name Zithromax® or Zmax®) is a broad-spectrum antibiotic used for a variety of bacterial, rickettsial, and parasitic infections. It is often combined with other drugs to treat specific infections, such as atovaquone to treat babesiosis in dogs. Azithromycin may also have anti-inflammatory, immune-modulating, and gastrointestinal motility effects.
In cats, it is used off-label to treat upper respiratory infections, bartonellosis, cryptosporidiosis, toxoplasmosis, or in combination with atovaquone to treat cytauxzoonosis. In dogs, it is used off-label to treat cryptosporidiosis, or in combination with atovaquone to treat babesia. It is also used for certain infections in horses, cattle, rabbits, guinea pigs, and birds.
What is Azithromycin?
Azithromycin is an antibiotic used in dogs and cats to treat respiratory, urinary and skin infections. Azithromycin is not available over the counter. It is a prescription drug and should only be administered under the guidance of a licensed veterinarian.
Azithromycin is a semi-synthetic antibiotic of the macrolide class, the same class as erythromycin and tylosin. This class of antibiotics acts to inhibit bacterial protein synthesis by inhibiting a cellular structure called a 50S ribosome, a structure that only certain bacteria have and use to make internal proteins.
Uses of this Medication
- Azithromycin has activity against many bacterial species, including Staphylococcus, Streptococcus, and Lyme disease.
- Azithromycin and atovaquone (a quinine derivative) combine to form an effective treatment against Babesia gibsoni, a blood cell parasite.
- Azithromycin has been able to combat the overgrowth of gum tissue (gingival hyperplasia), which is sometimes a side effect of cyclosporine, an immunomodulator.
- Azithromycin is often used for cats with chronic nasal disease/upper respiratory infection after other antibiotics have been found ineffective.
- Azithromycin can also improve gastrointestinal mobility, though it is usually used for its antibiotic properties.
- Azithromycin is often compared to its cousin erythromycin, and found to have a longer half-life in dogs and cats as well as better absorption of oral dosages. This means it lasts longer and gets into the body easier.
- This medication may be given with or without food.
- If a dose is skipped, do not double up on the next dose but simply resume dosing as usual with the next scheduled dose.
- Store away from light and store at room temperature. Do not refrigerate
Side effects
- Azithromycin overdose manifests as diarrhoea, vomiting, and abdominal cramps.
- Because azithromycin is largely removed from the body via the liver (in bile), normal liver function is needed to remove the drug from the body. If liver function is impaired, dosing adjustments may be required.