Pharmacological properties:

ATC vet classification code Q407 — antimicrobial veterinary drugs used for intestinal infections. QA07AAI0 – Colistin.
Colistin (polymyxin E) belongs to the natural antibiotics of the polypeptide group, synthesized by aerobic spore-forming bacillus Bacillus polymyxa var. Colistinus. It has a bactericidal effect mainly on gram-negative microorganisms (Escherichia coli, Salmonella spp., Shigeila spp., Pseudomonas aeruginosa, Klebsiella pneumoniae, Pasteurella spp., Haemophilus spp., Bordetella spp.). At the same time, gram-positive bacteria and certain types of gram-negative bacteria, in particular Serratia spp. and Proteus spp., have natural resistance to colistin.
The mechanism of antimicrobial activity is to disrupt the integrity and permeability of the cytoplasmic membrane of the bacterial cell.
Colistin interacts with membrane phospholipids, increasing their permeability to internal and external components, which leads to cell destruction. Additionally, it is able to bind phospholipid A and neutralize the biological effect of bacterial endotoxin.
When administered orally, colistin is almost not absorbed in the digestive tract, is not destroyed by digestive enzymes, due to which a high local concentration of the antibiotic is formed in the intestine. It does not accumulate in tissues and organs, is excreted mainly in unchanged form with feces and only a small amount - with urine (when used in high doses). The degree of excretion reaches 90-99 %.
In chickens, after oral administration of a dose of 50 mg/kg body weight, the highest colistin levels were detected after two hours: 10.2 μg/ml in serum and 5.7 μg/ml in bile. In pigs, oral administration of 25 mg/kg provided concentrations of 1.0 μg/ml in serum and 4.0 μg/ml in bile, and a dose of 50 mg/kg provided concentrations of 8.3 μg/ml and 9.0 μg/ml, respectively. The half-life after oral administration is approximately 4-4.5 hours, and the elimination rate is approximately
3 ml/kg/min. In calves after oral administration, its presence in the blood serum was not recorded.

Clinical features
Animal species

Cattle (calves up to 2 months old), pigs, poultry (broiler chickens, laying hens, turkeys).

Indications for use

Treatment of calves (up to 2 months of age), pigs and poultry (broiler chickens, laying hens, turkeys) for diseases of the digestive tract caused by microorganisms sensitive to colistin.

Contraindication

Do not use in animals with hypersensitivity to colistin or any of the excipients, as well as in animals with kidney disease.
Do not use simultaneously with other antimicrobial drugs.
Do not use in ruminants with functionally developed antechambers.
Do not use in animals for prophylaxis and in cases of direct or cross-resistance of microorganisms.

Side effect

When using the drug in recommended doses, no complications are observed. In some cases, allergic reactions may occur. In this case, the drug will be discontinued and desensitization therapy will be prescribed.

Special precautions for use

When using the drug, generally accepted and local principles for the use of antimicrobial drugs should be taken into account. Since, in human medicine, colistin is prescribed to combat infections caused by multi-resistant microorganisms, it should be used in animals only taking into account the results of susceptibility testing of pathogens to colistin. Use of the drug in violation of the instructions given may lead to an increase in the number of bacteria resistant to colistin and a decrease in the effectiveness of antibacterial therapy.

Use during pregnancy, lactation, and egg production

Without reservations.

Interaction with other means and other forms of interaction

Do not use simultaneously with other antimicrobial drugs. The action of colistin is inhibited by divalent cations Ba2+, Ca2+ and Mg2+, Fe3+, unsaturated fatty acids and ammonium compounds.
If significant concentrations of colistin are reached in the blood, the effect of other nephrotoxic drugs (aminoglycosides, cephalosporins, cyclosporine) may be enhanced.

Doses and methods of administration to animals of different ages

Orally with drinking water in doses:

– calves (up to 2 months old) – 60,000-120,000 IU of colistin sulfate per 1 kg of body weight. This corresponds to 1.0-2.0 g of the drug per 100 kg of body weight once a day.
Apply with drinking water or milk for 3-5 days. pigs – 60000-120000 IU colistin sulfate per 1 kg of body weight, which is equivalent to 1.0-2.0 g of the drug per 100 kg of body weight once a day. You can also use 200 g of the drug per 1000 l of drinking water. The course of treatment is 3-5 days.
– poultry (hens, chicks, turkeys) – 75,000 IU of colistin sulfate per 1 kg of body weight, which is equal to 1.25 g of the drug per 100 kg of body weight daily.
Alternatively, you can use 100-200 g of the drug per 1000 l of drinking water. Duration of use - 3-5 days.
The working solution of the drug is prepared before use by diluting in a ratio of 1:10. After dissolving the drug in drinking water, this solution must be used within 24 hours.

Overdose (symptoms, emergency measures, antidotes)

Overdose may cause digestive disorders (flatulence, diarrhea), as well as signs of neuro- and nephrotoxicity.

Special precautions
None.

Withdrawal period (withdrawal period)

Slaughter of animals and poultry for meat is allowed 3 days after the last application of the drug. Eggs are used without restrictions. Meat obtained before the specified period is disposed of or fed to unproductive animals, depending on the conclusion of a veterinarian.

Special precautions for persons and service personnel

During work, the general rules of personal hygiene and safety precautions provided for when working with veterinary medicinal products should be observed. All work should be carried out using protective clothing and personal protective equipment. In case of accidental contact of the drug with the skin or mucous membranes, it should be washed off with running water.