What is florfenicol used for?

Posted on  February 8, 2021, Edited by Jason, Category  

What is florfenicol?

1. Definition

Florfenicol is a synthetic monofluoro derivative of Thiamphenicol, white or off-white crystalline powder, odorless. The molecular formula is C12H14Cl2FNO4S. It is slightly soluble in water, chloroform and glacial acetic acid, soluble in methanol and ethanol. It is a new veterinary chloramphenicol broad-spectrum antibacterial drug successfully developed in the late 1980s.

It was first marketed in Japan in 1990. In 1993, Norway approved the drug to treat salmon furunculosis. In 1995, France, the United Kingdom, Austria, Mexico and Spain approved it for the treatment of bovine respiratory bacterial diseases. In Japan and Mexico, it is also approved as a feed additive for pigs to prevent and treat bacterial diseases in pigs. China has now passed the approval of the drug.

2. Traits

This product is white or almost white crystalline powder, odorless, and bitter. This product is soluble in dimethylformamide and methanol, slightly soluble in glacial acetic acid, water and chloroform.

3. History

"Chloramphenicol" is an antibiotic that everyone is familiar with, but after the use of chloramphenicol, it has very serious side effects (can inhibit bone marrow and cause aplastic anemia in animals). Therefore, since 2002, all animals that can be eaten by humans have been banned the access to chloramphenicol, including pigs, chickens, ducks and fish.

Afterwards, on the basis of chloramphenicol, a chloramphenicol derivative "thiamphenicol" was produced. Compared with thiamphenicol, whose bactericidal ability of thiamphenicol is enhanced, and side effects are reduced. However, symptoms such as "myelosuppression" and "anemia" can appear possibly. Therefore, there is still a slight deficiency in thiamphenicol, so its use in animals is subject to certain restrictions.

In the late 1980s, after further improvement of thiamphenicol, a new derivative was finally obtained. Its bactericidal ability was further enhanced and the side effects of "anemia" were completely eliminated. This is florfenicol.

Just as the new veterinary drug "Mei Ting" replaced the forbidden drug malachite green, the emergence of florfenicol at that time also caused a sensation in the entire scientific community. Since florfenicol was first used in the treatment of marine fish in Japan in 1990, after nearly 30 years of verification in Europe, the United States, China, etc., florfenicol is still a safe and efficient bactericidal drug. In 2013, after scientific compatibility, China's Haibei successfully launched florfenicol for aquatic products-Haifukang.

4. Pharmacological effects

Florfenicol has a broad-spectrum antibacterial effect by inhibiting the activity of peptide acyltransferase. It has a broad antibacterial spectrum, including various Gram-positive and negative bacteria and mycoplasma. Sensitive bacteria include Haemophilus bovine and swine, Shigella dysenteriae, Salmonella, Escherichia coli, Pneumococcus, Influenza bacillus, Streptococcus, Staphylococcus aureus, Chlamydia, Leptospira, Rickettsia, etc.

This product can disperse into bacterial cells for its fat solubility, mainly acting on the 50s subunit of the bacterial 70s ribosome, inhibiting transpeptidase, hindering the growth of peptidase and inhibiting the formation of peptide chains, thereby preventing protein synthesis. This product has a broad antibacterial spectrum, and has strong effects on Gram-positive bacteria, Gram-negative bacteria and Mycoplasma. Florfenicol has rapid oral absorption, wide distribution, long half-life, high blood concentration and long blood drug maintenance time.

Florfenicol uses


1. Indications

Florfenicol is used in chicken colibacillosis and duck serositis, salmon killer bacteria, Vibrio anguilla, etc., and intestinal infections of cattle, pigs and chickens caused by sensitive bacteria and chronic respiratory tract caused by mycoplasma disease.

2. Scope of application

A. Pigs

  • Infectious pleuropneumonia, asthma, parahaemophilus disease, pneumonia, erysipelas, atrophic rhinitis, streptococcal disease, eperythrocytosis, typhoid fever and paratyphoid fever;
  • Post-weaning multiple system failure, respiratory syndrome, unknown high fever and other respiratory diseases in pigs; swine dysentery, colitis, ileitis, piglet red, yellow and white diarrhea and other digestive tract diseases, as well as secondary diseases caused by multiple causes Symptoms and complications.

B. Chicken

Chicken chronic respiratory disease, infectious rhinitis, mycoplasma, influenza, pullorum, etc.

C .Duck

Pasteurellosis of duck disease, infectious serositis of duck, duck colibacillosis, etc.

D. Aquatic products

Red leg disease, larval bacteremia, crustacean ulcer disease, black gill and gill rot disease, filamentous bacterial disease of shrimp caused by Vibrio, Streptococcus, Pseudomonas, Edwards and Aeromonas, and Bacterial outbreaks such as limb rot disease, water mold disease, tremor disease of river crab, vibriosis of fish, hemorrhagic disease, enteritis, red skin, rotten tail, and rot.

3. Application

A. Pig

Treatment of sudden infectious pleuropneumonia, Haemophilus parasuis, swine pneumonia, streptococcus suis, etc. on the pig farm: at the initial stage of the disease, when the affected pigs still have a good appetite, increase the dosage when mix feeding and medicine, 60-80g of florfenicol per ton of feed.

It is best to add 200g of doxycycline for 7 days. For fever, cough, and asthma caused by infectious diseases, antibiotics can enough. If the sick pig has a fever and does not eat, it should be treated in isolation and intramuscular injection of florfenicol injection is needed. If the body temperature exceeds 41℃, it can be used with antipyretic analgesics and dexamethasone.

B. Chicken, Duck and Goose

It can treat intestinal diseases, respiratory diseases and mycoplasma infections caused by avian sensitive bacteria and mycoplasma infections, such as avian colibacillosis, pullorum, pasteurosis, typhoid fever, paratyphoid fever, cholera, poultry intestinal bacterial infection, pericarditis, perhepatitis, peritonitis, bacterial swollen head syndrome, necrotizing enteritis, duck infectious Serositis and so on.

Symptoms: birds stretch their necks and open their mouths to breathe, panting, tracheal bleeding, head shaking, runny nose, swollen head, enteritis, dysentery, salpingitis, etc.;

necropsy: liver enlargement, liver and heart surfaces are yellow with white Cellulose membrane, yellow cheese-like secretions in the air sacs, etc.

C. Aquatic products

In many areas, florfenicol has misunderstandings because of its high price and low frequency of use. Many people think that florfenicol has strong bactericidal power and side effects. If it is not used well, it will cause the fish to die. Therefore, it is not a last resort to choose florfenicol. Some people even think that florfenicol is the "nuclear weapon" of antibiotics, which is powerful and harmful! The truth?

Under the dual constraints of China’s food safety and environmental protection, aquatic drugs also advocate no or less antibiotics. Therefore, China has strict control of antibiotics, and resolutely eliminates the listing of drugs with large side effects. Therefore, in recent years, some antibacterial drugs have been listed as banned drugs. For example, norfloxacin was also on that list since last year.

So far, the Ministry of Agriculture has approved 12 kinds of antibiotics and synthetic antimicrobials that can be used in aquatic products, among which the commonly used varieties are: neomycin sulfate, doxycycline hydrochloride, florfenicol, enrofloxacin.

It can be seen that florfenicol is still allowed to be used under increasingly strict national standards, which can also prove that the harm or side effects of florfenicol are not so great.

Florfenicol has high antibacterial activity against many common pathogens in aquaculture. Florfenicol is used in aquaculture to control sensitive bacterial diseases. It has been proven to be effective in the treatment of yellow tail catfish pseudotuberculosis, channel catfish Edwards disease, channel catfish aeromonas versicolor, and Atlantic salmon scabies.

4. Water-soluble florfenicol

Florfenicol has great practical value, but there is still a problem: it is difficult to dissolve in water, so the utilization rate is low, and it cannot fully exert its efficacy. This problem has not been solved well.

Florfenicol, synthesized under the action of chiral organozinc and YH-3 catalyst, dissolves quickly in water. After entering the animal body, the biological activity is enhanced through the body's metabolism. The curative effect against avian colibacillosis, duck serositis and swine asthma is better than that of florfenicol.

Water-soluble florfenicol solves the problems of livestock and poultry drinking water and aquatic animal baths. The effect is the same as that of raw materials, but the bioavailability is higher. It is an ideal medicine for the treatment of bacterial diseases of livestock, poultry and aquatic animals, with good effect and adaptability.

Florfenicol side effects


1. Adverse reactions

Florfenicol has an immunosuppressive effect, which can easily cause cell gene chain reorganization and decrease the body's resistance. It also has embryo toxicity, so it should be used with caution for livestock during pregnancy and lactation. This product is mainly used for bacterial diseases of cattle, sheep, pigs, dogs, cats, chickens and fish caused by sensitive bacteria.

  • Although florfenicol has fewer side effects than chloramphenicol, and it will not cause irreversible bone marrow aplastic anemia, it can still cause dose-related damage to the hematopoietic system and the reversible bone marrow erythropoiesis inhibition is more common than chloramphenicol. The clinical manifestations are anemia due to inhibition of red blood cell production or accompanied by a decrease in white blood cells and platelets.
  • Strong immunosuppressive effect. Florfenicol's immunosuppression is about 6 times stronger than chloramphenicol. Because it inhibits antibody synthesis, it is contraindicated during vaccination or for those with severely impaired immune function.
  • Embryonic toxicity. It should be used with caution for sows during pregnancy and lactation. In addition, high-dose application of florfenicol can cause peripheral circulatory failure in newborn piglets, so newborn piglets should avoid using it.
  • Long-term oral administration can cause digestive disorders, vitamin deficiency symptoms, mild vomiting, diarrhea, etc.
  • Double infection can cause lung and gastrointestinal and urinary tract infections such as Pseudomonas aeruginosa, Staphylococcus aureus, fungus, etc.

2. Cautions

  • This product should not be used in combination with macrolides, lincosamides and diterpenoid semi-synthetic antibiotics-tiamulin. It can produce antagonistic effects when combined.
  • This product cannot be used in combination with beta lactone amines (such as penicillins, cephalosporins) and fluoroquinolones (such as enrofloxacin, ciprofloxacin, ofloxacin, etc.), because it is a quick-acting bacteriostatic agent that inhibits the synthesis of bacterial protein. Under the action of the former, bacterial protein synthesis is quickly inhibited, and the bacteria stop growing and reproducing, which weakens the bactericidal effect of the latter. Therefore, it cannot be used together when the treatment requires rapid sterilization.
  • Florfenicol cannot be mixed intramuscularly with sulfadiazine sodium. Do not combine with alkaline drugs during oral or intramuscular injection to avoid decomposition. It should not be mixed intravenously with tetracycline hydrochloride, kanamycin, adenosine triphosphate, coenzyme A, etc. to avoid precipitation and ineffective effect.
  • After intramuscular injection, it may cause muscle degeneration and necrosis. Therefore, it can be injected alternately in the deep muscles of the neck and buttocks. It is not advisable to repeat the injection at the same site.
  • Because florfenicol may have embryo toxicity, it should be used with caution for livestock during pregnancy and lactation.
  • In the prevention and treatment of porcine respiratory syndrome (PRDC), some people recommend the combination of florfenicol and amoxicillin, florfenicol and tylosin, or florfenicol and tiamulin. This method is not appropriate. Because from a pharmacological point of view, those two cannot be combined. But florfenicol can be combined with tetracyclines, such as doxycycline.


Florfenicol is a synthetic derivative of Thiamphenicol, which is a special veterinary medicine. Florfenicol has a good effect on bacterial infections of pigs, chickens, ducks, geese, fish and shrimps, but attention should be paid to the correct usage and dosage of florfenicol.

BALLYA provides a ballya-florfenicol-test to tell you if there are florfenicol residues in meat you may eat every day.


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