Doxycycline is a broad-spectrum bacteriostatic agent that works by inhibiting protein synthesis. Other similar drugs from the tetracycline class include
Oxytetracycline,
Tetracycline, and
Chlortetracycline. Tetracyclines have activity against gram-positive and gram-negative bacteria, including some anaerobes. It is also active against
Chlamydia, Mycoplasmas, and some protozoa, and several rickettsiae. Specific bacteria within the tetracycline's activity range include
Escherichia coli, Klebsiella spp, Pasteurella spp, Salmonella spp, Staphylococcus spp, and
Streptococcus spp.
The half-life elimination of doxycycline in chickens is 4.8 hours. The bioavailability in chickens is 41.3% (20 mg/kg dose).
Caution: Prolonged treatment can have catabolic and immunosuppressive effects, reduce normal gut flora, and increases the risk of opportunistic secondary infections. Birds with existing liver or kidney disease should be closely observed when given this medication.
Egg Withdrawal Period: Doxycycline is not approved for use in poultry producing eggs intended for human consumption in any country. However, multiple studies have been performed to evaluate the depletion of doxycycline in the eggs of treated hens. It is associated with a 7-day withdrawal period for chickens intended for meat purposes.
Storage/Stability: Doxycycline hyclate tablets and capsules should be stored in tight, light resistant containers at temperatures less than 30°C, and preferably at room temperature (15-30°C). After reconstituting with water, the monohydrate oral suspension is stable for 14 days when stored at room temperature.
