Diclofenac (Surpass)

Diclofenac, marketed for equine use as Surpass, represents a unique approach to non-steroidal anti-inflammatory therapy in horses by providing targeted topical delivery directly to affected joints and soft tissues. Unlike systemic NSAIDs that distribute throughout the body after oral or injectable administration, topical diclofenac allows anti-inflammatory medication to be applied precisely where it is needed, potentially reducing exposure of organs such as the gastrointestinal tract and kidneys to the drug. Surpass utilizes liposomal technology to enhance penetration of diclofenac through the skin and into underlying joint and periarticular tissues, achieving therapeutic concentrations at the application site while minimizing systemic absorption.

The mechanism of action of diclofenac mirrors that of other NSAIDs, involving inhibition of cyclooxygenase enzymes that catalyze production of inflammatory prostaglandins from arachidonic acid. By blocking prostaglandin synthesis locally, diclofenac reduces the pain, swelling, and tissue damage associated with inflammation in the applied area. The liposomal formulation of Surpass enhances drug delivery by encapsulating diclofenac within lipid vesicles that facilitate penetration through the stratum corneum and deeper skin layers to reach target tissues. Studies have demonstrated measurable diclofenac concentrations in synovial fluid and periarticular structures following topical application.

Surpass cream is approved by the FDA for control of pain and inflammation associated with osteoarthritis in the hock, knee, fetlock, and pastern joints of horses. The product comes as a white cream dispensed from multi-dose tubes, with each measured dose delivered using a ribbed applicator or measured by length of cream expressed from the tube. Application requires rubbing the cream into the affected area until absorbed, which also provides beneficial massage to the treatment site. The topical nature of administration makes Surpass particularly appealing for horses that resist oral medication, have gastrointestinal concerns that limit systemic NSAID use, or when targeted local therapy is preferred over systemic treatment.

While topical administration reduces systemic exposure compared to oral or injectable routes, diclofenac is not without potential for adverse effects. Local skin reactions at the application site can occur, and some degree of systemic absorption does take place, particularly with repeated application to large areas. The drug remains a prescription medication requiring veterinary supervision to ensure appropriate case selection, proper application technique, and monitoring for any adverse effects. Diclofenac is regulated in competition horses, and withdrawal times must be observed by performance horse owners and trainers.

The primary FDA-approved indication for Surpass topical diclofenac cream in horses is control of pain and inflammation associated with osteoarthritis in specific joints including the hock, knee, fetlock, and pastern. Osteoarthritis is a progressive degenerative condition affecting joint cartilage and surrounding structures that causes pain, stiffness, and reduced performance in horses of all ages and disciplines. While oral NSAIDs have long been used for arthritis management, topical diclofenac offers an alternative that delivers anti-inflammatory medication directly to affected joints without the same level of systemic exposure. This targeted approach may be particularly valuable for horses with mild to moderate joint inflammation where localized therapy can provide adequate relief.

Beyond the labeled indication for osteoarthritis, veterinarians may prescribe Surpass for various other conditions involving joint or periarticular inflammation. Synovitis, inflammation of the joint lining without significant cartilage damage, responds to topical anti-inflammatory therapy. Post-exercise joint soreness and inflammation in performance horses may benefit from targeted treatment following competition or training. Chronic low-grade joint inflammation that requires ongoing management but does not warrant continuous systemic NSAID therapy represents another scenario where topical diclofenac finds application.

Soft tissue inflammation in accessible locations may be treated with topical diclofenac, though penetration through tissues varies depending on the depth and location of the affected structures. Superficial soft tissue swelling from minor injuries, contusions, or overuse may respond to topical anti-inflammatory application. Inflammation associated with splints, windpuffs, and other common equine leg conditions may show improvement with Surpass treatment. The massage action involved in application may provide additional benefit beyond the pharmacological effect of the drug itself.

Surpass finds particular value in situations where systemic NSAID use is problematic or undesirable. Horses with histories of gastrointestinal sensitivity to oral NSAIDs may tolerate topical therapy better since systemic exposure is reduced. Patients with compromised kidney function who cannot safely receive full-dose systemic NSAIDs might benefit from localized treatment. Horses requiring long-term anti-inflammatory support may use topical therapy to reduce cumulative systemic drug exposure over time. However, topical diclofenac should not be viewed as completely free of systemic effects, and appropriate patient selection remains important.

Veterinarians may incorporate Surpass into multimodal treatment protocols alongside systemic medications, joint injections, or physical therapy approaches. The ability to provide additional anti-inflammatory effect to specific joints while managing other aspects of a horse's condition systemically offers flexibility in treatment design. Performance horses may use topical diclofenac for localized post-competition recovery while observing withdrawal requirements for competition purposes.

Dosing of Surpass topical diclofenac cream follows label recommendations specifying the amount of cream to apply based on the joint or area being treated. The standard application is a five-inch ribbon of cream applied to the affected area twice daily. For larger joints or areas, multiple application sites around the joint may be used to ensure adequate coverage. The cream should be measured consistently using the tube markings or a measuring guide to ensure reproducible dosing. Each five-inch ribbon delivers approximately 73 mg of diclofenac sodium in the liposomal cream base.

Proper application technique is essential for optimal drug delivery and therapeutic effect. The treatment area should be clean and dry before application. Hair may be clipped if necessary to allow better skin contact, though application over normal hair coat is acceptable if thoroughly rubbed in. The cream should be applied directly to the skin over the affected joint and rubbed in using a circular massaging motion until absorbed. Massage action helps work the product into the tissue and provides additional therapeutic benefit. Complete absorption may take several minutes, during which continued rubbing is beneficial. Wearing gloves during application protects against human drug exposure.

The recommended treatment duration is up to ten days, after which veterinary reassessment should occur to evaluate response and determine if continued therapy is appropriate. Longer treatment courses may be prescribed based on individual patient response, but extended use warrants monitoring for local skin reactions and any signs of systemic effects. Treatment should not continue indefinitely without periodic veterinary evaluation of the underlying condition and therapeutic response. If no improvement is seen within the initial treatment period, the diagnosis and treatment approach should be reconsidered.

Timing of applications should maintain approximately twelve-hour intervals for twice-daily dosing. Consistent timing helps maintain therapeutic drug levels in target tissues. Application can be incorporated into morning and evening care routines. After application, the treatment area should be allowed to dry before bandaging if wrapping is part of management. Standing wraps or bandages applied over treated areas may enhance penetration but should be used according to veterinary guidance.

Missed applications should be given as soon as remembered, with resumption of the regular schedule afterward. If close to the next scheduled application, the missed dose can be skipped to avoid over-application. Consistent twice-daily application provides optimal results, but occasional missed applications are unlikely to significantly impact overall response. Never apply extra cream to compensate for missed applications.

For horses with bilateral joint issues, each joint should be treated separately with its own measured application. When treating multiple joints simultaneously, awareness of total drug exposure is important, as cumulative application to large total areas increases systemic absorption. Veterinary guidance on treating multiple sites concurrently helps ensure safe total drug exposure.

Topical diclofenac is generally well tolerated by horses, with the localized delivery route reducing systemic side effects compared to oral or injectable NSAIDs. However, potential adverse effects exist and should be recognized by owners and veterinarians. The most common side effects involve local skin reactions at the application site, while systemic effects are less frequent but possible, particularly with application to large areas or extended treatment duration. Monitoring treated areas and overall patient status during therapy enables early recognition of any problems.

Local skin reactions represent the most commonly observed side effects with Surpass use. Application site reactions may include redness, scaling, dryness, crusting, or peeling of the skin in the treated area. Some horses develop contact sensitivity characterized by localized itching, swelling, or irritation. Minor reactions may resolve with continued use as the skin adapts, but significant reactions warrant treatment discontinuation. Hair loss at the application site has been reported in some horses. Any unusual skin changes in treated areas should prompt veterinary consultation to determine whether treatment can continue.

Systemic side effects are less common with topical diclofenac compared to oral administration but can occur since some drug absorption does take place. Signs of systemic effects would mirror those of any NSAID and could include decreased appetite, changes in manure consistency, or signs of gastrointestinal discomfort. Significant systemic effects are most likely when the cream is applied to large areas, used more frequently than recommended, or when treated areas are occluded with bandages that enhance absorption. Recognizing that topical does not mean zero systemic exposure guides appropriate use.

Gastrointestinal ulceration, the major concern with systemic NSAIDs, is much less likely with topical diclofenac but cannot be considered impossible, particularly with extensive or prolonged use. The drug's mechanism of action remains the same regardless of delivery route, and once absorbed systemically, it can affect the gastrointestinal tract. Horses with pre-existing gastrointestinal disease or sensitivity should be monitored for any signs of GI distress during topical diclofenac treatment.

Rare adverse events reported with diclofenac use include hypersensitivity reactions beyond the local application site and potential effects on organ systems with significant systemic absorption. Any unexpected clinical signs developing during Surpass treatment should prompt veterinary evaluation. Individual horses may show idiosyncratic responses that differ from typical experience, reinforcing the value of monitoring during any medication course.

Diclofenac topical cream should not be applied to horses with known hypersensitivity to diclofenac, aspirin, or other NSAIDs. Horses that have experienced allergic reactions to any NSAID, whether administered topically, orally, or by injection, may be at risk for similar reactions to diclofenac. Previous reactions might have included hives, facial swelling, respiratory distress, or severe local skin reactions. Cross-reactivity between NSAID classes can occur, so any history of NSAID sensitivity should be disclosed to the prescribing veterinarian before Surpass therapy begins.

Application to broken, infected, or severely compromised skin is contraindicated due to potential for increased absorption, irritation, and interference with wound healing. Open wounds, lacerations, or areas of active skin infection should not be treated with diclofenac cream. Wait until skin integrity is restored before applying topical NSAIDs to previously damaged areas. Similarly, application to mucous membranes or areas where the product might contact eyes should be avoided due to potential irritation and enhanced absorption.

While topical administration reduces systemic exposure, horses with severe gastrointestinal ulceration, significant kidney disease, or bleeding disorders should use diclofenac with caution or not at all, particularly if treatment involves large areas or extended duration. The drug does achieve some systemic levels, and patients with compromised organ function may be vulnerable even to relatively low systemic concentrations. Alternative local therapies such as cold application or physical modalities may be more appropriate for these patients.

Pregnant mares should avoid topical diclofenac treatment unless the therapeutic benefit clearly outweighs potential fetal risks, as some systemic absorption does occur and NSAIDs can affect fetal development and parturition. Lactating mares may receive treatment with appropriate monitoring of nursing foals. Competition horses must observe withdrawal times, as diclofenac is a controlled medication under most equestrian governing body rules. Horses intended for slaughter for human consumption face prohibition or extended withdrawal requirements depending on jurisdiction.

The most important drug interaction consideration for topical diclofenac involves concurrent use with other NSAIDs, whether administered systemically or topically. While Surpass delivers drug locally with reduced systemic absorption, combining it with oral or injectable NSAIDs adds to total NSAID exposure and could increase the risk of adverse effects including gastrointestinal ulceration and renal compromise. Veterinary guidance should be sought before using topical diclofenac in horses already receiving systemic NSAID therapy. If combination therapy is deemed necessary, monitoring for adverse effects should be enhanced.

Combining topical diclofenac with systemic corticosteroids carries similar concerns as combining any NSAIDs with corticosteroids, namely increased gastrointestinal ulceration risk. Although topical delivery reduces this concern compared to systemic NSAID and corticosteroid combinations, awareness is appropriate, particularly for horses with GI sensitivity or those receiving treatment for extended periods. When both topical diclofenac and systemic corticosteroids are indicated, gastroprotective therapy may be considered.

Application of other topical products to the same area as diclofenac may affect drug penetration or cause local reactions. Combining Surpass with other liniments, topical medications, or counterirritants on the same treatment site may alter absorption or increase skin irritation risk. Generally, topical products should not be layered or mixed without specific veterinary guidance. If multiple topical treatments are needed, applying them to different areas or timing applications separately may be preferable.

Interactions affecting competition drug testing deserve consideration for performance horses. While topical application results in lower systemic levels than oral administration, diclofenac is still detectable in blood and urine following Surpass use. Combining topical diclofenac with other medications could potentially affect metabolism or detection patterns. Comprehensive medication records and consultation with regulatory veterinarians help ensure competition compliance when multiple treatments are used.

Monitoring during topical diclofenac therapy should include regular assessment of the application site for skin reactions and observation of the horse's overall condition for any signs of systemic effects. Check treated areas daily for redness, scaling, hair loss, or other skin changes that might indicate local reaction. Note any changes in appetite, attitude, or manure consistency that could suggest systemic NSAID effects. While significant systemic complications are uncommon with topical delivery, vigilance ensures early recognition of any problems. Extended treatment duration warrants closer monitoring than short courses.

Special populations require additional precautions with topical diclofenac use. Foals have thinner skin that may allow enhanced absorption, and their developing organ systems may be more susceptible to NSAID effects. Conservative use with careful monitoring is advisable in young horses. Geriatric horses may have compromised skin barrier function or underlying organ dysfunction that affects drug handling. Horses with a history of sensitivity to topical products or known skin conditions may be more likely to develop application site reactions.

Competition horse owners must carefully observe withdrawal time requirements for Surpass. The drug is regulated by the Fédération Équestre Internationale, United States Equestrian Federation, and state racing commissions as a controlled medication. Detection times reflect how long diclofenac remains identifiable in samples following application, while withdrawal times indicate recommended treatment-free periods before competition. Because individual variation in absorption and metabolism exists, conservative withdrawal time adherence is advisable. Consult current regulations and competition veterinarians when planning treatment timing around show or race schedules.

Human exposure precautions are important during Surpass application. The product can be absorbed through human skin, and diclofenac carries warnings regarding human exposure. Wear waterproof gloves when applying the cream and wash hands thoroughly afterward even if gloves were worn. Avoid contact with eyes or mucous membranes. Pregnant women or women trying to become pregnant should avoid handling the product due to potential reproductive effects. Keep the product away from children.

Long-term use considerations apply even to topical NSAIDs. Continuous treatment beyond the recommended duration should occur only with ongoing veterinary supervision. Periodic reassessment of the underlying condition helps ensure that topical therapy remains appropriate and effective. If response is inadequate, alternative or additional treatments should be considered rather than simply continuing ineffective therapy. The treatment area should be rested from product application periodically if extended courses are needed, allowing skin recovery.

Surpass topical diclofenac cream should be stored at controlled room temperature between fifteen and thirty degrees Celsius or fifty-nine to eighty-six degrees Fahrenheit. Avoid exposure to extreme heat or cold, which can affect the cream consistency and drug stability. Do not freeze the product. Store in a dry location away from direct sunlight. The tube should be recapped securely after each use to prevent contamination and drying of the product. Barn or tack room storage is acceptable if environmental conditions remain within appropriate ranges, though climate-controlled locations offer better stability.

Safe handling practices protect both the medication and the humans applying it. Always wear waterproof gloves when applying Surpass to prevent skin absorption by the handler. Diclofenac can penetrate human skin and may cause systemic effects or local sensitization with repeated exposure. After application, remove and dispose of gloves properly, then wash hands thoroughly with soap and water. Avoid touching face, eyes, or other body areas after handling the product until hands are washed. Keep the product away from children, both during storage and use.

Special precautions apply to pregnant women or women trying to conceive, who should not handle Surpass due to potential effects on human reproduction. Men and non-pregnant women should still minimize exposure through glove use and good hygiene. If accidental skin exposure occurs, wash the area immediately with soap and water. Eye contact requires immediate flushing with water and medical consultation if irritation persists.

Expiration dates should be observed, with product used before the manufacturer-specified date. Expired cream may have reduced efficacy or altered characteristics. Inspect the product before each use for any changes in color, consistency, or odor that might indicate degradation. Properly dispose of expired or degraded product according to local regulations. Do not dispose of pharmaceutical products by flushing or pouring down drains. Veterinary take-back programs or pharmacy disposal services provide appropriate disposal options.

Draft horse breeds present certain practical considerations for topical diclofenac application related to their larger joint surface areas and often denser hair coats. Larger joints may require extended application areas to achieve adequate coverage, potentially increasing total drug exposure. Heavy feathering on lower legs common in breeds such as Clydesdales and Shires may interfere with cream contact with the skin unless hair is clipped or the product is worked thoroughly through the hair to reach the skin surface. The larger body mass of draft horses may reduce the relative systemic exposure from a given topical dose compared to smaller horses.

Light horse breeds and warmbloods typically follow standard application recommendations without significant modification. Performance horses in these categories represent a substantial portion of Surpass use, with the product commonly applied for post-exercise recovery and management of chronic low-grade joint inflammation. Competition horses require careful attention to withdrawal time requirements. Sport horses often have finer hair coats that allow good product contact with skin without clipping. The relatively lean conformation of many performance breeds facilitates palpation of joint structures to ensure accurate application placement.

Ponies and miniature horses have proportionally smaller joints that may require less cream per application. These smaller equines often have fine coats allowing good skin contact. However, their smaller body mass means that a given amount of absorbed drug produces relatively higher systemic levels per kilogram compared to larger horses. Conservative application amounts and careful monitoring are advisable. Many ponies and miniature horses suffer from metabolic conditions affecting joint health, and while topical diclofenac may provide symptomatic relief, comprehensive metabolic management remains essential.

Breed-specific conditions affecting joints may influence topical diclofenac use. Warmbloods with developmental orthopedic disease may receive topical treatment for associated joint inflammation. Quarter Horses commonly develop degenerative joint disease of the lower limbs suitable for topical management. Certain breeds have conformational characteristics that predispose them to specific joint problems potentially amenable to local anti-inflammatory therapy. Individual patient assessment rather than breed generalization should guide treatment decisions, recognizing that variation within breeds often exceeds variation between breeds.

Within the topical NSAID category available for horses, Surpass remains the primary FDA-approved veterinary product. Human topical diclofenac products exist but differ in formulation and are not specifically approved for equine use. Other topical preparations including various liniments and counterirritants are available but work through different mechanisms than prostaglandin inhibition. Compounded topical NSAID preparations may be available through veterinary compounding pharmacies but lack the regulatory approval and studied efficacy of commercial products.

Systemic NSAIDs represent the alternative approach to anti-inflammatory therapy when topical delivery is insufficient or impractical. Phenylbutazone provides excellent efficacy against bone and joint pain through oral or injectable administration. Flunixin meglumine offers potent anti-inflammatory effects with particular efficacy against visceral pain. Firocoxib provides COX-2 preferential inhibition with potentially improved gastrointestinal safety for extended use. The choice between topical and systemic therapy depends on the severity and extent of inflammation, patient factors affecting systemic NSAID tolerance, and practical considerations regarding treatment administration.

Complementary approaches may be used alongside topical diclofenac to provide comprehensive joint support. Joint supplements containing glucosamine, chondroitin, hyaluronic acid, and other supportive compounds provide nutritional building blocks for cartilage health. Intra-articular injections deliver medication directly into joint spaces for targeted therapy. Physical therapy modalities including cold therapy, therapeutic ultrasound, and controlled exercise programs address joint health through non-pharmacological means. Systemic joint support products may complement local topical therapy. Any modifications to treatment plans should be coordinated with the treating veterinarian to ensure appropriate integration of multiple approaches and monitoring for combined effects.