Food Animal Drugs

Food Animal NSAIDs and Analgesics

Remember : Analgesics need to be given prior to the pain stimulus to prevent hyperalgesia and wind-up phenomenom. This preemptive analgesia decreases the amount of pain produced but does not prevent pain. Analgesics should also be used after the stimulus to control the resultant pain. Pain is generally but not always related to the release of inflammatory mediators.

Our current practice “standards” are to 1) give nothing or 2) give it after the procedure. Neither of these make economic or physiological senseIt makes more sense to give the drug before the procedure, particularly if a single dose. The same dose given after the procedure has less effect. We have spent the same amount of money and effort for less result. Since our goal is generally production, avoiding drugs is also nonsensical. When drugs are given, production losses due to withholding are typically minimal and are offset by minimized drop in production of milk or meat related to pain.

Flunixin meglumine

Flunixin meglumine is the only NSAID currently (6/2018)  approved in food animals in the USA. In cattle, it needs to be given intravenously unless in the new topical formulation (below). Besides being off label, intramuscular injections are very irritating to tissues and can lead to Blackleg (clostridial myositis). Standard doses are 1.1 mg/kg iv BID or 2.2 mg/kg iv SID. You will find references for 2.2 mg/kg BID but that dose increases the risk of side effects.

FDA Approves First Medication for Pain Control in a Food-producing Animal

July 25, 2017

The U.S. Food and Drug Administration announces the approval of Banamine Transdermal (flunixin transdermal solution), an animal drug approved for the control of pain associated with foot rot and the control of pyrexia (fever) associated with bovine respiratory disease.

Meloxicam

Meloxicam is an NSAID that has gained widespread popularity. It seems to have better analgesic properties than flunixin meglumine. It is being used under ELDU (extralabel drug use) regulations for its analgesic effects. This does require a VCPR (veterinarian-client-patient relationship),

Castration  Guidelines AABP.org

There are no approved pain drugs for use in cattle in the US. The AMDUCA allows extra label drug use (ELDU) provided a valid VCPR exists and the drug selection decision process is followed. Although flunixin meglumine is an NSAID labeled for use in cattle and has been shown to have short acting analgesic effects, long acting NSAID analgesics, such as meloxicam, are more desirable to mitigate the pain associated with castration and dehorning.

While most oral medications are not effective in ruminants and camelids due to passage through the forestomachs, meloxicam is effective when given orally to both cattle and camelids. It may also be effective in piglets if fed to the sow.

Impact of Transmammary-Delivered Meloxicam on Biomarkers of Pain and Distress in Piglets after Castration and Tail Docking2014, PLoS One

The objectives of the study were to demonstrate meloxicam transfer from sows to piglets via milk and to describe the analgesic effects in piglets after processing through assessment of pain biomarkers and infrared thermography (IRT)… This study demonstrates the successful transfer of meloxicam from sows to piglets through milk and corresponding analgesia after processing, as evidenced by a decrease in cortisol and PGE2 levels and maintenance of cranial skin temperature.

FARAD suggests 21 days meat withholding after a single dose of 1mg/kg meloxicam po or 0.05 mg/kg im or iv: Considerations for extralabel drug use in calves, FARAD Digest, 2017

Poultry can also be given 1 mg/kg meloxicam. Contact FARAD for egg and meat withholding

Narcotics

Narcotics are increasingly used for pain in ruminants and camelids. None are approved so AMDUCA guidelines must be followed. These are the most common choices:

Butorphanol

Used for acute pain, generally perioperatively. The short duration of action makes it expensive and challenging to use long term. Provides sedation when combined with other drugs.

Butorphanol is a partial agonist-antagonist so should not be used in combination with other narcotics (it will decrease their effectiveness).

Minimal side effects.

Dose at 0.05–0.2 mg/kg IM or IV, every 1-3 hours

Reversal: naloxone

Morphine

Commonly used in ruminants for pain. Inexpensive and lasts  up to 8 hours. Does decrease GI motility and is a schedule II drug so requires careful monitoring of access to the drug.

Doses range from 0.05 – 0.1 mg/kg im or iv. Start with the lower dose to minimize side effects. If given iv, give slowly. The dose can be repeated in 4-6 hours.

Reversal: naloxone

Buprenorphine

Most commonly used for postoperative pain management in goats. Should be used with caution in sick animals due to side effects. Relatively expensive but a single dose is often effective.

Dose 0.0015–0.006 mg/kg IM or IV. Can be repeated in 4-6 hours but may last longer.

Reversal: naloxone

Fentanyl

Rarely used. May be used iv for perioperative pain control. The patches are more useful for control of camelid pain.

Try 150–225µg/kg/h.

Patches can take 4 hours to provide analgesia and last 36-48 hours.

Reversal: naloxone

One more transdermal option for poultry (warning – not serious):

 

Resources

Clinical Pharmacology of Analgesic Drugs in Cattle. Veterinary Clinics of North America: Food Animal Practice, March 2015, Vol.31(1), pp.113-138- bovine review with more pharmacology included

Assessment and Management of Pain in Small Ruminants and Camelids. Veterinary Clinics of North America: Food Animal Practice, March 2013, Vol.29(1), pp.185-208. Nice review with recommendations

A Review of Analgesic Compounds Used in Food Animals in the United States, 2013 VCNA Vol.29(1), pp.11-28

Approaching Pain in Cattle, AABP brochure

Formulary – Wiley Library

License

Icon for the Creative Commons Attribution-NonCommercial 4.0 International License

Large Animal Surgery - Supplemental Notes by Erin Malone, DVM, PhD; Elaine Norton, DVM PhD; Erica Dobbs, DVM; and Ashley Ezzo, DVM is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License, except where otherwise noted.