METACIN 50 (powder for oral administration)

A powder ranging from light yellow to yellow-brown in colour, with the characteristic odour of its constituents.

1 g of the product contains the active substance:

- doxycycline hyclate – 500,0 mg.

Excipient: citric acid.

ATC vet classification code QJ01 – antibacterial veterinary medicines for systemic use. QJ01AA02 – Doxycycline.

Doxycycline is a bacteriostatic antibiotic belonging to the tetracycline group. Its mechanism of action involves inhibition of microbial protein synthesis. Doxycycline blocks the binding of aminoacyl-tRNA to the ribosomal A-site (acceptor site), thereby inhibiting elongation of the peptide chain and arresting protein synthesis. The product has a broad spectrum of antimicrobial activity against Gram-positive (Staphylococcus spp., Diplococcus pneumoniae, Streptococcus spp., Bacillus anthracis, Clostridium tetani, C. perfringens, Pasteurella spp., Listeria monocytogenes, Bordetella bronchiseptica) and Gram-negative (E. coli, Haemophilus influenzae, Enterobacter spp., Klebsiella spp., Salmonella spp., Shigella spp., Yersinia spp.) bacteria, as well as mycoplasmas (Mycoplasma spp.), rickettsiae (Rickettsia spp.), and chlamydiae (Chlamydia spp.).

Doxycycline is rapidly and almost completely absorbed in the intestine, is well distributed, and penetrates most tissues of the calves' body. In calves, the half-life of doxycycline following oral administration at a dose of 10 mg/kg body weight per day ranged from 15 to 28 hours. Plasma doxycycline levels reached a mean concentration of 2,2–2,5 µg/mL.

In pigs following oral administration, doxycycline at a dose of 10 mg per 1 kg body weight per day reaches a maximum plasma concentration of 1,30 µg/mL, and the plasma elimination half-life is 7,01 h. The plasma protein binding level is 93%. The elimination half-life of doxycycline is 3,9 hours.

In chickens, the maximum plasma concentration of doxycycline was 2,05 ± 0.47 µg/mL and was reached within 6 hours of the start of treatment, ranging from 1,28 to 2,18 µg/mL at a dose of 25 mg/kg body weight. At therapeutic plasma concentrations, the degree of protein binding is 70–85%. In chicks, the elimination half-life is 4.8 hours.

The greater part of doxycycline is excreted unchanged in the faeces, and partly in the urine.

Calves up to 8 weeks of age: treatment of respiratory tract diseases (bronchopneumonia, pleuropneumonia, and others) and gastrointestinal tract diseases (colibacillosis, salmonellosis) caused by microorganisms susceptible to doxycycline.

Pigs: treatment of respiratory tract diseases (bronchopneumonia, pleuropneumonia, atrophic rhinitis, and others) and gastrointestinal tract diseases (colibacillosis, salmonellosis) caused by microorganisms susceptible to doxycycline.

Domestic poultry (broiler chickens, replacement pullets): treatment of birds affected by colibacillosis, salmonellosis, chlamydiosis, septicaemia, as well as respiratory tract diseases caused by microorganisms susceptible to doxycycline.

- calves up to 8 weeks of age – 1,0–2,0 g of the product per 100 kg body weight (5–10 mg doxycycline per 1 kg body weight) with drinking water, feed, milk, or milk replacer, twice daily for 3–5 days;

- pigs – 2,0–4,0 g of the product per 100 kg body weight once daily (10–20 mg doxycycline per 1 kg body weight), or 200 g of the product per 1,000 L of drinking water daily for 3–5 days;

- domestic poultry (broiler chickens, replacement pullets) – 0,4–0,5 g of the product per 10 kg body weight per day (20–25 mg doxycycline per 1 kg body weight per day), or 100–200 g of the product per 1,000 L of drinking water daily for 5 days.

To obtain a precise dose of the product in drinking water, calculate the required quantity of product using the formula:

To prepare an aqueous solution of the product for poultry, pour the required volume of drinking water (preferably warm) into a small container, then add the product in small portions with continuous stirring until the powder is completely dissolved. The concentrate thus prepared (product-to-water ratio of 1:10) is immediately added to the required volume of drinking water in accordance with the water intake rates for the respective age groups of poultry. A fresh solution of the product must be prepared daily.

Do not use in animals with known hypersensitivity to tetracyclines or to any of the excipients of the product.

Do not use in laying hens whose eggs are intended for human consumption.

Do not use in animals with impaired renal or hepatic function.

Do not use in animals in which resistance to doxycycline has been identified in the herd or flock.

Do not use in ruminants with a functional rumen.

Do not use concomitantly with penicillin-group or cephalosporin-group antibiotics, quinolones, or cycloserine, or with antacids or kaolin.

Do not use together with products containing metal ions (antacids, preparations containing Mg²⁺, Al³⁺, Ca²⁺, Zn²⁺, Fe³⁺).

In isolated cases, allergic reactions (skin rash, pruritus, and oedema) and digestive disturbances (anorexia, vomiting, diarrhoea) are possible. Should these occur, administration of the product must be discontinued and desensitising therapy initiated.

High doses or prolonged use of the product may cause a neurotoxic effect (e.g. ataxia).

In some EU countries, resistance to tetracyclines has been established in E. coli isolated from chickens, Pasteurella spp. isolated from calves, and in pathogens causing respiratory diseases in pigs (A. pleuropneumoniae, S. suis).

In the presence of any infectious process, bacteriological confirmation of the diagnosis and determination of the susceptibility of the causative bacteria to doxycycline are recommended. Use of the product contrary to the instructions may increase the prevalence of tetracycline-resistant bacteria and may reduce treatment efficacy.

Do not use in laying hens whose eggs are intended for human consumption.

The product is not recommended for use in animals during pregnancy or lactation due to possible neurotoxic effects. Use of the product is permissible only when it is evident that the benefit of treatment clearly outweighs the potential adverse consequences.

No data are available regarding the embryotoxic, teratogenic, or mutagenic effects of doxycycline.

Slaughter of animals and poultry for meat is permitted 8 days (pigs), 7 days (poultry), and 14 days (calves) after the last administration of the product. Meat obtained prior to the stated withdrawal period must be disposed of or fed to non-food-producing animals, as directed by the attending veterinarian.

Polyethylene or polymer film sachets/bags of 1, 2, 5, 10, 50, 100, 500 g and 1 kg. 

Bags of 20 and 25 kg. 

Polymer containers of 100 and 500 g, 1 kg.

Store in a dry, dark place, out of reach of children, at a temperature of 15 °C to 25 °C.

2 years.

Shelf life after first opening of the sachet: 28 days, provided the opened container with the product is stored at a temperature of 15 to 25 °C in a dry, light-protected place.

Shelf life after reconstitution: 24 hours.