A long-acting injectable form of the drug omeprazole has shown promise in treating stomach ulcers in horses.
The effectiveness of the drug was assessed in a recent Australian study, the findings of which have been published in the Equine Veterinary Journal.
Omeprazole is commonly prescribed for acid reflux in humans and is available for horses as an oral paste to treat stomach ulcers, given daily.
Benjamin Sykes, from the University of Queensland, and his colleagues noted that pilot investigations had suggested that the long-acting injectable form, given into the muscle, can induce acid suppression for up to 7 days following one dose.
The researchers conducted their research in two-parts – a pharmacodynamic study involving six adult thoroughbreds and a pilot clinical trial involving 26 horses with gastric ulcers, identified through gastroscopic examination.
In the second part, horses received 2.0 grams of the 100 mg/mL long-acting omeprazole formulation by injection into the muscle at the start of the study, and again seven days later. Gastroscopic examinations were repeated on day 14 for all but one of the horses, who had his on the 16th day.
Ulcer healing was observed in all 22 horses that had lesions in the upper squamous part of the stomach and in nine of the 12 horses with lesions in the lower glandular part of the stomach.
Improvement by at least one grade was observed in all 22 horses with squamous disease and in all 12 with glandular disease.
The researchers acknowledged that the work involved a small number of horses, but said the findings compared favourably with previous reports on the pharmacodynamics of omeprazole and the clinical outcomes of trials reporting response to oral omeprazole therapy.
Sykes, B. W., Kathawala, K., Song, Y., Garg, S., Page, S. W., Underwood, C. and Mills, P. C. (2017), Preliminary investigations into a novel, long-acting, injectable, intramuscular formulation of omeprazole in the horse. Equine Vet J. doi:10.1111/evj.12688
The abstract of the study can be read here.