Analgesic medications can relieve acute pain from an injury and help a horse suffering from chronic discomfort. When it comes to giving any medication to a horse, it’s important to be aware of the potential for unwanted consequences.

Knowing some of the adverse side effects and discussing these possibilities with your veterinarian can make sure your horse receives the benefits of pain-relieving drugs with a minimum of negative side effects. Here are the most common side effects of equine pain relievers.

  1. Masking Pain

One important risk of a powerful analgesic is that it can mask pain so well that a horse doesn’t take care to protect an injury. Too much activity can worsen an injury and lengthen healing time. Management strategies, such as safe confinement, are important to curtail an injured horse’s urge overuse the injured area. Using a minimum dose of an analgesic can keep pain to a reasonable level without elimintating it entirely; this encourages a horse to be protective of a leg injury, for example.

The masking of pain can be especially detrimental in colic cases. Some drugs, such as flunixin meglumine (Banamine), if given at maximum therapeutic dose, can actually disguise a surgical colic. For this reason, it is recommended to give a colicky horse only one-quarter of the dose normally administered for musculoskeletal injury. For example, a 1,000-pound horse would receive only 250-pound dose of flunixin at the onset of a colic crisis. This enables continual monitoring of improvement progress or deterioration that might necessitate aggressive medical therapy and/or surgery.

  1. Slowing Gastrointestinal Motility

Some pain relievers, such as opioids and some sedatives, have the unwanted side effect of slowing gastrointestinal (GI) motility, which then has the potential to lead to colic. Careful consideration of both dose and frequency for administration of these products is critical to minimizing undesirable GI effects. Careful monitoring of audible GI motility sounds and fecal output provides some oversight of how a horse is handling its drugs.

  1. Increase risk of Gastric Ulcer Disease

It is common knowledge that repeated doses of non-steroidal anti-inflammatory drugs (NSAIDs) such as phenylbutazone, flunixin meglumine, ketoprofen and even firocoxib, have the potential to elicit gastric and/or colonic ulcer disease. Many prostaglandins produced by the body are beneficial as protectants to the GI lining; yet, these anti-prostaglandin medications eradicate the action of the good prostaglandins along with diminishing production of prostaglandins related to inflammation.

An optimal goal relies on giving the least amount of analgesic medications to ease a horse’s discomfort. In some cases, it works best to combine different classes of pain-relieving medications in order to minimize side effects yet achieve good pain control. Your veterinarian can guide you on which products to have on hand and how best to use them