FDA Approves First Drug to Control Pain in a Food-Producing Animal
Controlling pain is important for the health of all animals, and FDA has recently approved the first pain control drug for use in a food-producing animal. Available only by a veterinarian’s prescription, Banamine Transdermal is approved to control pain associated with foot rot in cattle. Foot rot is a common cause of pain and lameness in cattle of all ages and breeds. The disease is seen in cattle that are housed in barns and feedlots and those out on pasture.
Foot Rot – A Painful Disease1
Foot rot is caused by bacteria that invade the foot through a break in the skin between the two toes. (In cattle, each foot has two toes.) The bacteria need some sort of injury, such as a cut, puncture wound, or severe abrasion, to penetrate the natural barrier of the skin. Walking on rough surfaces, such as sharp gravel, rocks, and hardened mud, or standing in a wet and muddy area for a long period of time can cause foot injuries in cattle.
Once the bacteria enter through the damaged skin, they move down into the underlying tissue and begin to quickly multiply and secrete toxins. As the infection worsens, the foot tissue starts to decay. In severe cases, the foot will abscess above the hoof, revealing a foul-smelling discharge. If the infection isn’t treated, the bacteria may invade the deeper tissues and even the joints and bones of the foot, resulting in permanent lameness.
The bacteria are common in the environment, especially in shady or wet areas. Not only can the bacteria be found on diseased feet, they can be found on healthy feet as well as in the feces of normal cattle. Bacterial contamination of the environment is the source of infection for other cattle in the herd. Once the bacteria are “seeded” in the soil, foot rot may recur in a herd for a long time.
Lameness due to pain is typically the first sign of foot rot, followed by other signs of inflammation, such as swelling and redness. As the swelling progresses, the toes begin to separate. The swelling and lameness can appear suddenly, with the animal walking normally one day and lame the next. Cattle with foot rot can lose weight because they’re reluctant to walk to their feed and water. They also may have a fever and loss of appetite.
Fortunately, prompt treatment of foot rot with an appropriate antibiotic is usually successful. If treatment is delayed, the prognosis is poor. Some mild cases will respond to topical therapy or get better spontaneously without treatment, but most cases require an oral or injectable antibiotic. Several antibiotics are FDA-approved to treat foot rot in cattle. After the antibiotic treats the underlying infection, the pain eventually subsides. Now, with the approval of Banamine Transdermal, the pain can be controlled sooner before the antibiotic takes effect.
Banamine Transdermal isn’t an antibiotic and doesn’t treat the bacterial infection of foot rot. The drug contains flunixin, a veterinary non-steroidal anti-inflammatory drug that controls pain and inflammation. It’s applied only once in a narrow strip along the animal’s back and is absorbed through the skin. People who handle Banamine Transdermal (mainly veterinarians and cattle producers) should wear personal protective gear that covers their eyes and skin to prevent exposure to the drug.
The drug’s label and Freedom of Information Summary include detailed user and animal safety information.
Hard to Detect Pain in Food-Producing Animals
A major challenge in showing that a drug controls pain in animals is that, unlike people, animals can’t verbalize where they hurt or their level of pain. Pain is particularly hard to detect in prey species, such as cattle and other food-producing animals. In the wild, any outward signs of sickness or weakness will be quickly detected by a predator. A limping, painful bison will be the first one in the herd killed by a hunting wolf. To survive, prey species like cattle have evolved to mask their physical signs of pain, making it hard for veterinarians and cattle producers to tell when they’re suffering.
“It’s hard to establish reliable ways to detect and measure pain in food-producing animals because they have such subtle pain responses,” explained Emily Smith, a veterinarian and drug reviewer at FDA’s Center for Veterinary Medicine (CVM).
Another complicating factor in detecting pain in food-producing animals is the variability in how they express pain. Not only does this variability extend across species, it also extends across breeds within a species and across procedures and diseases. For example, one cattle breed may express pain differently than another breed, and the pain behaviors seen in an animal with foot rot may be different than those behaviors seen with other painful diseases or after surgery.
Measuring Pain in Food-Producing Animals
Several drugs are already FDA-approved to control pain in cats, dogs, and horses. These companion animals typically live more intimately with their owners than food-producing animals, so their pain behaviors may be more noticeable and easier to detect. There are also more validated methods to assess pain in companion animals than in food-producing animals. Reliable and validated methods for assessing pain are necessary to determine how effective a drug is at controlling pain.
To show the effectiveness of Banamine Transdermal at controlling pain in cattle with foot rot, the drug company conducted a study that used both subjective and objective measurements. For the subjective measurement, a person experienced with cattle observed each animal several times during the study and assigned it a lameness score of 1 (normal gait) to 5 (severely lame). Pressure mats that measured the force and contact area of the foot with foot rot were used to objectively measure pain at several time points during the study. The less force and contact area of the foot, the more lame and painful the animal.
The study included two groups of cattle with foot rot. One group was given Banamine Transdermal and the other a saline placebo. Six hours later, the cattle given Banamine Transdermal had improved lameness scores and walked with increased force and contact area across the pressure mats, indicating they were less painful than cattle given the saline placebo.
Committed to Animal Health
“Having approved drugs available to control pain in food-producing animals is a positive contribution to veterinary medicine,” said Beth Luddy, a veterinarian and the deputy director of CVM’s Office of New Animal Drug Evaluation. “CVM is committed to working with drug companies to improve animal health.”
FDA’s Center for Veterinary Medicine promotes and protects animal health by making sure safe and effective drugs are available for animals. Working with drug companies to develop and approve drugs to control pain in all animals, including food-producing animals, is an important part of that mission.
(1) Step DL, Whitmore B, Giedt EJ, Lalman, D. Foot rot in cattle. Oklahoma Cooperative Extensive Service, ANSI-3355.
(2) Van Metre DC. Pathogenesis and treatment of bovine foot rot. Vet Clin Food Anim 2017;33:183-194.
(3) Whittier WD. Foot rot in cattle. Virginia Cooperative Extension, Livestock Update, January 1999.
Resources for You
- FDA Approves First Medication for Pain Control in a Food-producing Animal
- Freedom of Information Summary for Banamine Transdermal, New Animal Drug Application (NADA) 141-450
- From an Idea to the Marketplace: The Journey of an Animal Drug through the Approval Process
- T.A.L.K. Before You Treat