Antibiotic Pills & Drugs

UCD VET VIEWS
CALIFORNIA CATTLEMAN, OCTOBER 1998

This month, a new antibiotic for the treatment of respiratory disease in cattle is scheduled for release. This antibiotic is a member of a new class of antibiotics: fluoroquinolones. A previous column about fluoroquinolone antibiotics was written in this publication back in 1996 (February 1996; Fluoroquinolone antibiotic use in cattle). There has been a fair amount of controversy about this class of antibiotics in human medicine and veterinary medicine circles. The controversy revolves around the concern that bacterial resistance to the fluoroquinolones will develop and result in the emergence of "Super Bugs". These bacteria would then be resistant to the fluoroquinolones. These bacteria could infect humans, and no effective therapy would be available. Those concerned postulate that using these antibiotics in food animals, such as cattle, would accelerate the potential of developing bacterial resistance. While this concern has theoretical potential, the practical potential is extremely small or non-existent. This class of antibiotics is used routinely in human patients and in companion animal patients (including horses). These humans and animals are in much closer contact with other humans than the products of food animals. While the scientific merit of these concerns is questionable, the effects of this controversy will clearly affect the use of this antibiotic in cattle.

This new antibiotic will be marketed as Baytril® 100 and is administered as a subcutaneous injection. It is intended to be used as a treatment for respiratory disease in cattle. The bacterial organisms most commonly involved in respiratory diseases of cattle, such as pneumonia, include Pasteurella haemolytica, Pasteurella multocida, and Haemophilus somnus. These are the bacteria that Baytril® 100 is effective against. Respiratory disease caused by viruses will not be directly responsive to this antibiotic (or any other antibiotics for that matter). Antibiotics are commonly used, even in viral pneumonia, to help the animal fight off secondary bacterial invaders that take the opportunity to attack damaged lung tissue. Therefore, this antibiotic will be another drug that can be used to treat respiratory disease in cattle. Other drugs that are commonly used for this purpose include: LA 200® (long acting oxytetracycline), Biomycin 200® (another long acting oxytetracycline), Nuflor® (florfenicol), Polyflex® (ampicillin), Excenel ® (ceftiofur), Micotil 300® (tilmicosin), Naxcel® (ceftiofur), and several other antibiotic products too numerous to mention.

There will be significant differences in the way that this new product, Baytril®, can be used. First, this will not be an "Over-the-Counter" drug (OTC drug). It will be available only from your veterinarian as a veterinary legend drug and a valid veterinarian-client-patient relationship must be active. Your veterinarian will either provide the product directly to you or will write a prescription so that you can obtain the product from a certified third party (pharmacy, veterinary drug distributor, etc.). A valid veterinarian-client-patient relationship does not include situations such as, your brother-in-law who is a veterinarian in Seattle and visits your ranch every year or so. Your veterinarian must be familiar with your operation and have made a diagnosis of respiratory disease in the cattle that are to be treated with Baytril®.

Secondly, this drug can only be used as therapy for respiratory disease in cattle. It cannot be used to treat foot rot, pinkeye, calf scours, or other diseases. This product must be used only according to the label. The following aspects of the Baytril® label must be adhered to:

Species Approved-cattle only (not for use in cattle intended for dairy production or in calves to be processed for veal)

Disease-only for treatment of bovine respiratory disease associated with Pasteurella haemolytica, P. multocida, Haemophilus somnus

Dosage-only the approved dosage rates listed on the label

Frequency of treatment-only those listed on the label

Route of Administration-subcutaneous injections only

Withdrawal Time-animals must not be slaughtered within 28 days of the last treatment

Warning-Do not use in cattle intended for dairy production or in calves to be processed for veal

This product is not intended to be used in an extralabel manner. That is to say, it cannot be used in sheep, dairy cattle, etc. It cannot be given intramuscularly, or intravenously. It cannot be used at different dosage rates or frequency from those listed on the label. The withdrawal time must be adhered to (28 days). It cannot be used to treat calf scours or other diseases not listed on the label. In other words, your veterinarian will not be able to write an extralabel "prescription" for this product. While extralabel use is possible with some drugs, they will not be permitted with this product. This is a major departure from the routine situation. Before you decide to use this product in your cattle, consult with your veterinarian regarding all aspects of the use of this drug. Particular attention must be given to the legal limitations on the use of this product. Along these lines, if you are not currently keeping records on drug use in cattle-now is a good time to consider doing this on a routine basis. The use of this drug will be monitored like no other in the history of food animal drugs. Therefore, good records on the use of this product in individual animals or in groups of animals will be necessary in the event of a residue problem. This is not just a new product, it is a new way of using food animal drugs. Talk this situation over with your veterinarian carefully and completely.

John Maas, DVM, MS
Diplomate, ACVN & ACVIM
Extension Veterinarian
School of Veterinary Medicine
University of California, Davis

Source: http://www.vetmed.ucdavis.edu/vetext/INF-BE_cca/INF-BE_cca98/INF-BE_cca9810.html