Effectiveness of topical fentanyl for musculoskeletal pain in horses

Purpose

To evaluate the effectiveness and safety of a topical fentanyl solution compared to a control vehicle solution to reduce musculoskeletal pain.

Background

This is a controlled double-blinded prospective clinical trial for horses with musculoskeletal pain of the appendicular skeleton. The lower limbs of horses, and all animals, are prone to many traumatic injuries that can lead to acute or chronic inflammatory or degenerative conditions resulting in chronic pain and seen as a limp or lameness. The most common chronic conditions include osteoarthritis, tendonitis, desmitis (ligament injury) laminitis and navicular disease, but many acute injuries such as chip fractures, splints, stress fractures, and sesamoid fractures can also cause lameness. Osteoarthritis is a degenerative disease involving inflammation that affects joints with changes in the subchondral bone. The process causes progressively increasing pain and lameness. Tendonitis is a painful enlargement of an area of injured tendon that can fail to heal and result in scar tissue and lost of limb flexibility. Many limb diseases in horses have an inflammatory component that could benefit from new pain treatments, not just osteoarthritis.

New pain medications such as new classes or formulations of opioids can potentially provide pain relieve for conditions that previously could not be controlled with current medications, particularly in horses. In general, the opioid class of pain medications are the most potent and would be very relieving to horses with severe, acute (fresh fracture) pain or flare-­‐ups of a chronic condition. In horses, the discovery of a new method of safe and effective application could be very beneficial for horses in pain. The goal of this study is to prove that the application of this new formulation of an opioid (fentanyl) onto the skin is rapidly absorbed and relieves pain of the musculoskeletal system without side effects. This formulation has been tried on many horses and has not been associated with problems, but proof of the benefit for pain in horses has not been done.

Inclusion Criteria

  • Lameness located to a joint or distal limb by regional anesthesia up to 30 days prior to enrollment.

Study Design

If you decide to allow your animal to be enrolled, an x-ray or ultrasound, blood work, and gait analysis, as well as several noninvasive measurement may be performed. To study your horse’s lameness, your animal may be lead several times across an in-ground flat metal force place designed to measure the force with which step is taken. This will be performed up to 5 times while your horse is enrolled. The medications will be administered topically on the withers once. Your horse will be followed here at the Veterinary Medical Center for up to 1 week after treatment. During this time, your horse may receive physical examinations, measurements of inflammation such as a circumference of the limb, heat at the surface, force plate exams, blood work and possibly urinalysis. Your horse may also have an exercise program consisting of walk, trot, and canter, on a treadmill 2-3 times per week to keep the joints limber. Once the results confirm your animal can be enrolled, your horse will be assigned at random to one of two groups: either the control placebo group or the treatment group. Your horse may receive firocoxib orally (by mouth), either as a control medication or a rescue treatment depending of your horse’s level of pain. You will also be required to fill out a pre-study questionnaire and a 3-month follow-up questionnaire

Client Compensation

  • The costs for the data collection, testing, sedation, board, treadmill and force plate, blood and urine analysis and collection, and study treatment will be paid for by the sponsor of these studies. This includes physical exams, x-rays, ultrasound, and all biochemical and blood tests.

Client Cost

  • You will be notified the date of receiving the treatment and therefore the discharge day. You are expected to pick up your horse on the discharge day. If an unexpected event occurs and you cannot pick up your horse on the discharge day, you are allowed a 2-day grace period and then additional board will be charged to your credit card. You must provide a credit card at our reception prior to leaving your horse for this study

Contact

Alicia Bertone, DVM, PhD, DACVS, bertone [dot] 1 [at] osu [dot] edu