Endotoxemia remains the leading cause of death in horses. It is involved in the pathogenesis of gastrointestinal disorders that cause colic and neonatal foal septicemia.¹ Endotoxins, normally present within the bowel, gain access to the blood across damaged intestinal mucosa, or endotoxemia occurs when gram-negative organisms proliferate in tissues.

Endotoxemia can arise after a horse experiences an illness such as colic, pneumonia or a severe infection; it is a serious inflammatory response that can cause a horse’s vital organs to fail and its circulatory system to collapse. 

Symptoms of endotoxemia in horses can include:

• Fever
• Malaise
• Dehydration
• Dark mucous membranes 
• Sweating
• Increased heart and respiratory rate
• Intestinal shutdown
• Pain²

Numerous micro-organisms exist in the intestinal tracts of horses. In healthy horses, microbes in the bowel stop pathogenic bacteria from growing out of control. Endotoxins are the metabolites of gram-negative bacteria, many of which are present in the bowel. In most cases, bacteria and endotoxins are stopped from moving past the interior of the bowel by an intestinal barrier that includes epithelial cells, enzymes and antibodies. If these migrate outside the interior of the bowel and are not eliminated, it can lead to endotoxemia. 

In cases where endotoxins migrate through the mucosal barrier into the liver, immune cells help to eliminate them. In immunocompromised horses, the release of endotoxins can lead to a variety of health problems. 

Endotoxins are often present in environments where horses reside. Horse manure has high amounts of gram-negative bacteria, thus stabled horses can breathe in significant amounts of endotoxins.

A complete physical examination should be conducted; the veterinarian will typically request a complete blood count and an arterial blood gas analysis. In cases of endotoxemia, the complete blood count will often show leukopenia and neutropenia. The arterial blood gas will show arterial hypoxemia and signs of metabolic acidosis.²

Toxic metritis is the result of a severe inflammation involving all layers of the uterus which can develop after foaling, and is associated with dystocia and foaling trauma. It is typically marked by the presence of septicemia, endotoxemia, or both. Early clinical signs include vulvar discharge, lethargy, and fever. Endotoxins can quickly reach high levels, potentially leading to laminitis, organ dysfunction, and even death.^3,4

A retrospective study to develop treatment recommendations for affected mares evaluated the veterinary records of 45 mares that had been diagnosed with metritis within six days of foaling and treated with a variety of antimicrobial types. “Treating veterinarians had confirmed on culture that 28 (62.2%) of the mares were infected with more than one bacterial species, with the most common one being Escherichia coli (30.7%).”⁴

The study showed that 65.5% of mares were infected with both gram-negative and gram-positive bacteria, which have structural or functional differences that make some drugs more effective against them than others. For this reason, broad-spectrum antibiotics that act on both types of bacteria have been recommended.

Ticarcillin Disodium / Clavulanate Potassium for Horses

Ticarcillin Disodium / Clavulanate Potassium is used systemically to treat serious infections such as sepsis or nosocomial pneumonias in dogs, cats and horses. By adding clavulanate, enhanced spectrum of activity against beta-lactamase producing bacteria is obtained.⁵

Extended-spectrum penicillins such as ticarcillin/clavulanate are sometimes called anti-pseudomonal penicillins, and include both alpha-carboxypenicillins (carbenicillin and ticarcillin) and acylaminopenicillins (piperacillin).⁵ They have similar spectrums of activity as the aminopenicillins, but with additional activity against several gram-negative organisms of the family Enterobacteriaceae, including many strains of Pseudomonas aeruginosa.

Through the addition of clavulanate, ticarcillin’s efficacy is extended against beta-lactamase-producing strains of otherwise resistant E. coli, Pasteurella  spp.,  Staphylococcus  spp., Klebsiella, and Proteus. Clavulanic acid acts by competitively binding to beta-lactamases.⁵

Where to buy Ticarcillin Disodium / Clavulanate Potassium

Ticarcillin Disodium / Clavulanate Potassium is available in the U.S. through pharmaceutical manufacturers and through veterinary custom compounding companies. TICARCILLIN DISODIUM / CLAVULANATE POTASSIUM (SYRINGE) 3.1 GM by NexGen Pharmaceuticals is indicated for the treatment of endotoxemia brought on by gram-negative bacteria, as well as other internal bacterial infections affecting horses.

Please consult your veterinarian prior to beginning any treatment regimen.

FOR RX ONLY: A valid prescription from a licensed veterinarian is required for dispensing this medication.

¹Morris DD. Endotoxemia in horses. A review of cellular and humoral mediators involved in its pathogenesis. J Vet Intern Med. 1991 May-Jun;5(3):167-81. doi: 10.1111/j.1939-1676.1991.tb00944.x. PMID: 1920254.

²wagwalking.com.

³veteriankey.com.

⁴thehorse.com.

⁵Plumb’s Veterinary Drugs.