Zitrex® belongs to macrolide antibiotics.
Azithromycin is an azalide, a subclass of macrolide antibiotics
with broad-spectrum bacteriostatic activity against gram-negative
(Actinobacillus pleuropneumoniae, Actinobacillus lignieresi, Mannheimia
(Pasteurella) haemolytica, Pasteurella multocida, Legionella pneumophila,
Haemophilus spp., Moraxella spp., Bordetella spp., Campylobacter
spp., Fusobacterium spp., Salmonella spp., Escherichia coli) and grampositive bacteria (Listeria spp., Staphylococcus spp., Streptococcus spp.,
Clostridium perfringens) and Chlamydia spp. and Mycoplasma bovis and
Azithromycin binds to the 50S subunit of the bacterial ribosome,
thus inhibiting the peptide translocase on the translation stage.
The antibiotic inhibits protein synthesis, growth and reproduction
of bacteria. In high concentrations, it has a bactericidal effect.
Azithromycin has an effect on extracellular and intracellular
pathogens. The concentration in tissues and cells is 10-50 higher
than in plasma, and in nidus of infection it is 20-30% higher than in
Azithromycin has a postantibiotic effect – long-lasting inhibition of
bacteria after a short-term contact with the antibiotic. The effect is
based on irreversible changes in the bacterial ribosomes, which block
the translocation. It enhances and prolongs the antibacterial effect
of the drug.
Azithromycin is well absorbed from the injection site and distributed
to all organs and tissues after parenteral administration. The antibiotic
is transported by phagocytes, polymorphonuclear leukocytes, and
macrophages to the infection site. The maximum concentration is
reached in 30-60 minutes, the therapeutic concentration persists for
at least 72 hours, in lungs and macrophages – for at least 240 hours.
Azithromycin is excreted primary intact in the urine and bile.
Zitrex® is used to treat cattle, sheep and goats for necrobacillosis, mycoplasma infections and bacterial infections of respiratory and gastrointestinal tract, genitourinary system, skin and soft tissues caused by microorganisms sensitive to the antibiotic.
Zitrex® is a solution for injection. 1 ml contains active substance: 100 mg of azithromycin; excipients: N, N-dimethylacetamide, benzoic acid, benzyl alcohol, thioglycerin and water for injection.
Zitrex® is administered to cattle, sheep, goats and pigs once by intramuscular route at a dose of 1 ml per 20-40 kg bw (5 mg of azithromycin per 1 kg bw). In severe cases, it is recommended to repeat the injection. If animal weight exceeds 300 kg, the dose must be divided into smaller drug volumes that do not exceed 7.5 ml per one injection site.