Gastric juice<scp>pH</scp>measurement in horses: Three‐quarters of a century of history!

Andrews, Frank M.

doi:10.1111/eve.12505

Cited by 4 publications

(6 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A review on the history of intra-gastric measurement in the horse has recently been published [85] with the earliest report dating back to 1933…”

Section: Models Of Intra-gastric Ph Measurement In the Horsementioning

confidence: 99%

“…( [86] cited in [85]) when a gastric fistula was created in a horse allowing collection of gastric fluid and quantification of daily output from the live animal .…”

Section: Models Of Intra-gastric Ph Measurement In the Horsementioning

confidence: 99%

“…Early work in the 1990s evaluating the efficacy of different formulations of omeprazole in the horse was primarily performed using a gastric cannulation model [3,4,75,78,84] which was considered the model of choice at the time [85]. An advantage of this method was that it allows the measurement of gastric fluid pH, electrolytes and prostaglandins and the calculation of total daily gastric acid output.…”

Section: Models Of Intra-gastric Ph Measurement In the Horsementioning

confidence: 99%

“…Two key disadvantages of the model are that placement of the gastric cannulas requires general anaesthesia and surgical expertise and that total daily gastric acid output cannot be determined. Although it has been argued that total daily gastric acid output may be a more sensitive marker of the effect of acid suppressive drugs [85], the clinical relevance of the it is not clear as intra-gastric pH, and specifically the percentage of time that pH exceeds 3 or 4 within each inter-treatment period are considered the primary determinants of efficacy for glandular and squamous disease, respectively, in humans [88].…”

Section: Models Of Intra-gastric Ph Measurement In the Horsementioning

confidence: 99%

“…A final method for evaluating intra-gastric pH by aspirating gastric fluid during endoscopic examination has also been described [85,[90][91][92]. The advantages of this technique are that is it simple, quick and easy to perform.…”

Section: Models Of Intra-gastric Ph Measurement In the Horsementioning

confidence: 99%

See 4 more Smart Citations

Factors affecting the pharmacokinetics and pharmacodynamics of omeprazole in the horse

Sykes¹

View full text Add to dashboard Cite

Equine Gastric Ulcer Syndrome (EGUS) is a common condition of the horse, affecting a broad range of horse usages and types. Recently the terminology of the syndrome has been expanded to include terms Equine Squamous Gastric Disease (ESGD) and Equine Glandular Gastric Disease (EGGD) to describe diseases of the squamous and glandular mucosa of the stomach, respectively. Omeprazole, a proton pump inhibitor that blocks acid production, is considered the treatment of choice for EGUS and it has been widely used for this purpose for nearly 20 years. Yet, surprisingly, despite its widespread use little is known about the factors that affect its efficacy, such as the impact of formulation, diet and dose. Further, although it is commonly believed that the once daily administration of omeprazole results in durations of acid suppression exceeding 24 hours, there is conflict in the literature as to the validity of this belief. Recent clinical studies have demonstrated that the healing rate for EGGD is inferior to that of ESGD, raising further questions as to the efficacy of omeprazole under clinically relevant conditions. One potential reason for this observation is that the duration of intra-day acid suppression required for healing of ESGD may be less than that for EGGD. This, coupled with the possibility that once daily administration of omeprazole may not result in acid suppression for the entire 24 hour treatment interval, provides a potential explanation for the poor EGGD healing rates that have been recently reported. The purpose of this thesis was to investigate the factors that affect the efficacy of omeprazole in the horse. The studies were conducted in four parts; firstly, the effect of formulation and diet on the pharmacokinetics of omeprazole were investigated; secondly, a model that allows continuous intra-gastric pH measurement under clinically relevant conditions was developed; thirdly, the impact of diet and dose on the pharmacokinetics and pharmacodynamics of omeprazole were investigated; and lastly, the relationships between key pharmacokinetic and pharmacodynamic variables were investigated. The findings of the study suggested that some method of physical protection is required to protect the omeprazole from degradation in the acidic environment of the stomach and to improve bioavailability. However, significant differences were not present between formulations utilising the two most common forms of protection, namely the use of enteric coated granules in paste or buffering of the formulation. This suggests that the method of protection, buffering of the formulation or the use enteric coated granules in paste, used is less important than protection per se. The earlier studies of the thesis 3 suggested that an effect of feeding may be present on the pharmacokinetics of omeprazole but a statistically significant effect could not be demonstrated. Similarly, the latter studies suggested that diet may play a role in bioavailability with ad libitum roughage diets impairing absorption, but no statistically signi...

show abstract

“…A review on the history of intra-gastric measurement in the horse has recently been published [85] with the earliest report dating back to 1933…”

Section: Models Of Intra-gastric Ph Measurement In the Horsementioning

confidence: 99%

“…( [86] cited in [85]) when a gastric fistula was created in a horse allowing collection of gastric fluid and quantification of daily output from the live animal .…”

Section: Models Of Intra-gastric Ph Measurement In the Horsementioning

confidence: 99%