Evaluation of the effect of orally administered acid suppressants on intragastric pH in cats

Rational use of gastroprotectants in cats: An evidence-based approach

PRACTICAL RELEVANCE

Acid-related disorders including esophagitis and gastroduodenal ulceration are uncommon in the cat. However, when they occur, they can have devastating consequences and require targeted intervention, including the use of gastroprotectants. Careful consideration of the causes of esophagitis and gastroduodenal ulceration can help the clinician to determine which gastroprotectant to use, and when to begin and end gastroprotective therapy.

CLINICAL CHALLENGES

Gastroprotectants remain one of the most misused classes of drugs in veterinary and human medicine. There are very few studies evaluating the efficacy of gastroprotective agents in cats. Furthermore, goals for the degree of gastric acid suppression are extrapolated from studies performed in dogs and humans.

AIMS

This review provides a foundation for the logical approach to the choice of gastroprotectant as indicated by the disease process, and is aimed at all veterinarians who prescribe gastroprotectants for use in cats.

EVIDENCE BASE

The guidance provided in this review is supported by current literature, including consensus opinion from the American College of Veterinary Internal Medicine. Gaps in evidence for use of gastroprotectants in cats are filled by extrapolations from studies performed in dogs and humans.

Retrospective evaluation of the effect of acid suppressant drugs on leukocyte ratios in dogs with mast cell tumors

BACKGROUND

Acid suppressant drugs (ASDs) are commonly used to decrease gastric acid production, but some evidence exists that ASDs exert immunomodulatory effects. Such an effect has not been investigated in dogs for which ASDs are routinely prescribed.

HYPOTHESIS

Compared to naïve subjects, dogs treated with ASDs will exhibit differences in leukocyte ratios after treatment.

ANIMALS

Fifty-one dogs with mast cell tumors (MCTs).

MATERIALS AND METHODS

Dogs with MCT that were either AS naïve or treated with ASDs (i.e., histamine-2-receptor antagonists [H2RA] or proton pump inhibitors [PPI]) were included in this retrospective study. Subjects were categorized into 3 treatment groups (AS naïve, H2RA treated, and PPI treated), and leukocyte ratios (neutrophil:eosinophil, lymphocyte:monocyte, and neutrophil:lymphocyte [NLR]) were calculated before and after treatment. A mixed effects analysis of variance on ranks was used to assess differences in ratios between treatments, between pre- and post-treatment time points, and between pre- and post-time points for each treatment. Concurrent administration of antihistamines, corticosteroids, and chemotherapeutic drugs was assessed as a confounding factor.

RESULTS

Famotidine (n = 14/14) and omeprazole (n = 12/12) were the only H2RA and PPI used, respectively. Dogs receiving famotidine had a significant increase in median NLR from pre- to post-treatment (3.429; range, 1.417-15 to 5.631; range, 2.654-92; P < 0.01) compared to PPI treated or AS naïve dogs. No differences existed in chemotherapeutic drug or corticosteroid use between groups.

CONCLUSIONS

A significant difference in NLR was identified in famotidine treated dogs compared with omeprazole treated or AS naïve dogs.

Evaluation of gastroprotectant administration in hospitalized cats in a tertiary referral hospital

OBJECTIVES

The primary objective of this study was to evaluate the prescription patterns and appropriateness of the use of gastroprotectant medication in cats.

METHODS

Pharmacy dispensation logs from an academic tertiary referral center were reviewed between 1 January 2018 and 31 December 2018. Cats that were administered proton pump inhibitors (PPIs), histamine-2 receptor antagonists (H2RAs), sucralfate, misoprostol, antacids or a combination were included. Data regarding medication, dosage, formulation, duration of administration, completeness of discharge instructions and clinical rationales for administration were obtained from medical records. The appropriateness of gastroprotectant use was assessed according to the American College of Veterinary Internal Medicine consensus statement guidelines.

RESULTS

Of the 110 cases, 67 (60.9%) were prescribed a gastroprotectant medication without an appropriate indication. The most common reason for prescription was acute kidney injury in 26/67 (38.8%). PPIs were the most common gastroprotectant medication administered in 95/110 (86.3%) cats, followed by sucralfate in 18/110 (16.4%) and H2RAs in 11/110 (10%). Of the 35 cases in which gastroprotectant therapy was indicated, the medication chosen or dosage administered was considered suboptimal in 16 (45.7%). Instructions regarding the duration of administration, potential adverse effects and timing of administration in relation to meals or other medications were inconsistently provided in discharge instructions to pet owners. Of the 29 cases discharged with omeprazole, only 13 (44.8%) instructions included a duration of administration, while 6 (20.7%) recommended continuing gastroprotectants indefinitely until further notice, 16 (55.2%) discussed the timing of the administration in relation to a meal and six (20.7%) mentioned potential adverse effects; none advised tapering of omeprazole before discontinuation.

CONCLUSIONS AND RELEVANCE

When prescribed, gastroprotectant medications were frequently prescribed injudiciously to cats in this referral population over a 12-month period. Discharge instructions to pet owners also often lacked information and recommendations regarding optimal administration, potential adverse effects, and tapering or discontinuation of the medications.

Evaluation of gastrointestinal transit times and pH in healthy cats using a continuous pH monitoring system

OBJECTIVES

The aim of this study was to characterize gastrointestinal (GI) transit times and pH in healthy cats.

METHODS

GI transit times and pH were measured in six healthy, colony-housed, purpose-bred spayed female cats using a continuous, non-invasive pH monitoring system in a sequential order design. For the first period ('pre-feeding'), food was withheld for 20 h, followed by oral administration of a pH capsule. Five hours post-capsule administration, cats were meal-fed by offering them their daily allowance of food for 1 h. For the second period ('post-feeding'), food was withheld for 24 h and cats were fed for 1 h, after which a pH capsule was orally administered. Studies in both periods were repeated three times. GI transit times and pH were compared between the two periods.

RESULTS

The median transit times for the pre- and post-feeding periods, respectively, were: gastric - 94 mins (range 1-4101) and 1068 mins (range 484-5521); intestinal - 1350 mins (range 929-2961) and 1534 mins (range 442-2538); and GI - 1732 mins (range 1105-5451) and 2795 mins (range 926-6563). The median GI pH values for the first and second periods, respectively, were: esophageal - 7.0 (range 3.5-7.8) and 4.5 (range 2.9-6.4); gastric - 2.7 (range 1.7-6.2) and 2.0 (range 1.1-3.3); intestinal - 8.2 (range 7.6-8.7) and 7.8 (range 6.7-8.5); first-hour small intestinal - 8.2 (range 7.4-8.7) and 8.3 (range 7.9-8.6); and last-hour large intestinal - 8.5 (range 7.0-8.9) and 7.8 (range 6.3-8.7). Gastric (P <0.0020) and intestinal pH (P <0.0059) were significantly increased in the pre-feeding period compared with the post-feeding period.

CONCLUSIONS AND RELEVANCE

Gastric and intestinal pH differed significantly when the capsule was administered 5 h prior to feeding compared with 1 h after feeding. Transit times for both periods showed high degrees of intra- and inter-individual variability.

Gastrointestinal transit time is faster in Beagle dogs compared to cats

OBJECTIVE

To characterize gastrointestinal transit times (GITTs) and pH in dogs, and to compare to data recently described for cats.

ANIMALS

7 healthy, colony-housed Beagles.

PROCEDURES

The GITTs and pH were measured using a continuous pH monitoring system. For the first period (prefeeding), food was withheld for 20 hours followed by pH capsule administration. Five hours after capsule administration, dogs were offered 75% of their historical daily caloric intake for 1 hour. For the second period (postfeeding), food was withheld for 24 hours. Dogs were allowed 1 hour to eat, followed by capsule administration. Both periods were repeated 3 times. The GITTs and pH were compared to published feline data.

RESULTS

The mean ± SD transit times in dogs for the pre- and postfeeding periods, respectively, were esophageal, 3 ± 5 minutes and 13 ± 37 minutes; gastric, 31 ± 60 minutes and 829 ± 249 minutes; and intestinal, 795 ± 444 minutes and 830 ± 368 minutes. The mean ± SD gastrointestinal pH in dogs for the pre- and postfeeding periods, respectively, were esophageal, 6.6 ± 0.6 and 5.7 ± 1.0; gastric, 3.0 ± 1.4 and 1.8 ± 0.3; intestinal, 7.9 ± 0.3 and 7.7 ± 0.6; first-hour small intestinal, 7.6 ± 0.5 and 7.1 ± 0.4; and last-hour large intestinal, 7.9 ± 0.6 and 7.7 ± 1.0. The first-hour small intestinal pH and total transit times varied between dogs and cats depending on feed period (P = .002 and P = .04, respectively). Post hoc analysis revealed significantly shorter total transit times in dogs prefeeding (P = .005; mean ± SD for cats, 2,441 ± 1,359 minutes; for dogs, 828 ± 439 minutes) and postfeeding (P = .03; mean ± SD for cats, 3,009 ± 1,220 minutes; for dogs, 1,671 ± 513 minutes). Total transit time for dogs was also shorter pre- versus postfeeding (P = .003).

CLINICAL RELEVANCE

GITT is faster in Beagles compared to cats, but gastrointestinal pH are similar when fed the same diet.

Prescribing habits for the use of omeprazole as a gastroprotectant in dogs in a veterinary teaching hospital

OBJECTIVES

To examine the prescribing habits for omeprazole in a veterinary teaching hospital and to evaluate the effect of a clinical audit on omeprazole prescription.

MATERIAL AND METHODS

Observational study with retrospective clinical audit followed by a prospective study. The evaluated data about omeprazole prescription included the dose, frequency and indication. These were assessed according to published guidelines. A seminar about the audit and current guidelines on the use of omeprazole was organised for all members of clinical staff. Prospective data collection was conducted after the seminar. A comparison of the collected data before and after the clinical audit was made.

RESULTS

A total of 301 dogs were prescribed omeprazole in the veterinary teaching hospital during the study period (including the retrospective and prospective parts). Complete data were acquired from 240 patients. The prescribed frequency of omeprazole was inappropriate in 23 (16.5%) of the prescriptions in the retrospective section but in only five (5.0%) in the prospective study. Inappropriate indications were reported in 12 (8.6%) patients in the retrospective section and in two patients (2.0%) in the prospective study. Overall inappropriate omeprazole prescription was identified in 34 (24.5%) patients in the retrospective part and in seven (6.9%) patients in the prospective part. There was a statistically significant difference between the two groups in frequency, indication and overall prescription of omeprazole.

CLINICAL SIGNIFICANCE

This study details the frequency of inappropriate prescription of omeprazole in a veterinary teaching hospital and provides some evidence that dissemination of guidelines based on clinical audit can improve prescribing habits.

Appetite-stimulating effects of once-daily omeprazole in cats with chronic kidney disease: Double-blind, placebo-controlled, randomized, crossover trial

Background

Cats with moderate to advanced chronic kidney disease (CKD) often display clinical signs such as vomiting and decreased appetite, and frequently receive omeprazole or other acid suppressants despite a lack of evidence to support their use.

Hypothesis/Objectives

To evaluate the effect of once‐daily PO omeprazole on appetite in cats with CKD. We hypothesized that omeprazole would improve subjective appetite assessments in cats with CKD.

Animals

Fourteen client‐owned cats with International Renal Interest Society (IRIS) stage 2 or 3 CKD and hyporexia.

Methods

Cats were prospectively enrolled in a multi‐institutional, double‐blinded, randomized, crossover study to evaluate the effect of a 14‐day trial of once‐daily PO omeprazole (1 mg/kg) or placebo (lactose gel capsule) on vomiting frequency and appetite. A daily log was completed by the owner during all treatment and rest periods to assess appetite using a subjective, qualitative, and 5‐point scoring system. Mixed model analyses of variance were performed to determine if average daily percentage food consumed or appetite score, as measured by subjective owner assessment, differed between treatments.

Results

Compared to placebo, a negligible but statistically significant difference in percentage of food consumed was observed between treatments (P = .04) with once‐daily omeprazole treatment resulting in a 2.7% increase in food consumption compared to placebo. No significant difference, however, was found in appetite score, body weight, or serum creatinine concentration between treatments.

Conclusions and Clinical Importance

Once‐daily omeprazole does not markedly increase appetite in cats with CKD and should not be used as a first‐line treatment in the absence of evidence of gastrointestinal ulceration.

Survey-Based Analysis of Current Trends for Prescribing Gastrointestinal Protectants among Small-Animal General Practitioners in Portugal

In both human and veterinary healthcare, gastrointestinal protectants (GIPs) are considered a staple of clinical practice in that they are prescribed by general practitioners (GPs) and specialists alike. Concerning GIP use, overprescription of proton pump inhibitors (PPIs) has become a growing concern among human healthcare providers. This trend has also been documented within veterinary practice, prompting the American College of Veterinary Internal Medicine (ACVIM) to publish a consensus statement in 2018 concerning evidence-based indications for GIP use. This observational cross-sectional study evaluated self-reported prescribing protocols among Portuguese GPs to determine whether there is adherence to the consensus guidelines. Respondents were Portuguese GPs recruited by social media posts in veterinarian online forums. Data were collected from 124 respondents concerning their GIPs of choice and their rationales for prescribing them. Data were mined for prescription patterns and protocols. Among GIPs, PPIs were prescribed more often. Rationales for use included gastrointestinal ulceration and erosion (GUE), prophylactic management of nonerosive gastritis, pancreatitis, reflux esophagitis, and steroid-induced ulceration. Once-daily administration of PPIs was the most frequent dosing regime among respondents. Ninety-six percent of PPI prescribers advocated that the drug be administered either shortly before or at mealtime. Forty-nine percent of respondents supported long-term use of PPIs. Fifty-nine percent of respondents acknowledged discontinuing PPIs abruptly. This study supports that Portuguese GPs commonly prescribe GIPs in accordance with ACVIM recommendations to medically manage GUE. However, misuse of GIPs does occur, and they have been prescribed where their therapeutic value is debatable. Educational strategies should target GPs in an effort to reduce GIP misuse.

Gastroprotective Therapy

A range of gastroprotective drugs are available for the treatment of esophagitis and gastroduodenal mucosal injury including acid suppressants (ie, histamine-2 receptor antagonists, proton pump inhibitors), coating agents, prostaglandin analogs, and antacids. Of these, the proton pump inhibitors are the most effective drugs for the medical treatment of upper gastrointestinal injury. However, proton pump inhibitors are not effective for all causes of upper gastrointestinal injury. The choice of gastroprotective drug should be guided by the cause and location of gastrointestinal injury and the potential for adverse effects.

Comparative analysis of the effect of PO administered acid suppressants on gastric pH in healthy cats

BACKGROUND

Proton pump inhibitors (PPIs) are among the most commonly prescribed medications for esophagitis and upper gastrointestinal erosion and ulceration in cats. Newer PPIs such as lansoprazole and esomeprazole are believed to be effective in cats, but the effect of many of these PPIs on gastric pH in cats has not been explored.

HYPOTHESIS/OBJECTIVES

To evaluate the efficacy of PO esomeprazole, dexlansoprazole, and lansoprazole on intragastric pH in healthy cats. We hypothesized that esomeprazole and lansoprazole would provide superior acid suppression compared to dexlansoprazole and reach pH goals extrapolated from people for the treatment of esophagitis and duodenal ulceration.

ANIMALS

Twelve healthy research cats.

METHODS

Randomized, 3-way crossover study. Cats were given esomeprazole and lansoprazole at a dosage of 1 mg/kg PO q12h or dexlansoprazole at 6 mg/kg PO q12h. Intragastric pH was recorded at baseline and for 4 days of treatment. Mean pH and the mean percentage time (MPT) intragastric pH was ≥3 or ≥4 were compared among and within treatment groups.

RESULTS

Cats treated with lansoprazole had a lower MPT ± SD of intragastric pH ≥3 (8.8 ± 6.8%) and mean ± SD pH (1.6 ± 0.5) than did cats treated with dexlansoprazole (41.2 ± 34.6% and 3.11 ± 1.6, respectively) or esomeprazole (54 ± 33.8% and 4.1 ± 3.9, respectively;P ≤ .04). Esomeprazole was the only treatment that achieved the goals defined for people for the treatment of duodenal ulceration by Day 4 of treatment (MPT ± SD of intragastric pH ≥4 of 77.1 ± 29.2%).

CONCLUSIONS AND CLINICAL IMPORTANCE

Orally administered esomeprazole might be a superior acid suppressant in cats compared to PO lansoprazole or dexlansoprazole.

Complex Disease Management: Managing a Cat with Comorbidities

Many older cats often suffer concurrently from multiple conditions. By focusing on the common concerns, rather than conflicting requirements, a management program can be devised. Optimize hydration, nutrition, and ensure comfort though providing analgesia and a low-stress environment in which the patient's feline-specific nature is respected both in the clinic and at home. Additional requirements, such as hyperphosphatemia or hypokalemia, can be met using treatments outside of diet, if necessary.

Gastrointestinal Diseases of Ferrets

Disease of the gastrointestinal (GI) tract is common in ferrets. This chapter reviews diseases of the upper and lower GI tract in ferrets, discusses how to differentiate between causes of diarrhea and vomiting, and provides information to help formulate an appropriate treatment plan. Clinicians should be familiar with the more common GI disorders in ferrets and be able to recognize clinical signs and differentiate among potential diagnoses.

Clinical findings, diagnostic test results, and treatment outcome in cats with hiatal hernia: 31 cases (1995-2018)

Background

Information regarding clinical signs, assessment, treatment, and outcome in cats with hiatal hernia (HH) is limited.

Objectives

To characterize the clinical presentation of HH and medical and surgical outcomes in a cohort of affected cats.

Animals

Thirty‐one client‐owned cats with HH.

Methods

Medical records of cats with HH were retrospectively reviewed for signalment, history, results of diagnostic tests, details of surgical and medical treatments, complications, and outcome. Long‐term follow‐up data were obtained by telephone communication. Relationships between clinical variables and outcome were evaluated by regression analysis.

Results

Type I HH was present in 85.7% (24/28) of cats, and 64.5% (20/31) were >3 years of age at diagnosis. Twenty‐one of 31 (67.7%) cats underwent surgical repair including phrenoplasty, esophagopexy, and left‐sided gastropexy, and 10 of 31 cats were treated medically without surgery. Concurrent illness was common, and 77.4% cats had comorbidities. All cats survived to discharge, and median time to death or follow‐up was 959 days (range, 3‐4015 days). Cats treated medically survived longer than cats treated surgically, with median time to death or follow‐up of 2559 and 771 days, respectively.

Conclusions and Clinical Importance

Type I HH is the most common type of HH in cats. A congenital etiology is possible, but many cats with HH were >3 years of age at diagnosis and suffered from comorbidities, including upper airway obstruction. Case selection and the presence of comorbidities likely influenced the outcome. Cats with HH may not be diagnosed until disease is advanced or concurrent illness draws attention to clinical signs.

Gastrointestinal Tract Dysfunction With Critical Illness: Clinical Assessment and Management

The gut is the site of digestion and absorption as well as serving as an endocrine and immune organ. All of these functions may be affected by critical illness. This review will discuss secondary effects of critical illness on the gut in terms of gastrointestinal function that is clinically observable and discuss consequences of gut dysfunction with critical illness to patient outcome. Because there is little evidence-based medicine in the veterinary field, much of our understanding of gut dysfunction with critical illness comes from animal models or from the human medical field. We can extrapolate some of these conclusions and recommendations to companion animals, particularly in dogs, who have similar gastrointestinal physiology to people. Additionally, the evidence regarding gut dysfunction in veterinary patients will be explored. By recognizing signs of dysfunction early and taking preventative measures, we may be able to increase success with treatment of critical illnesses.

The frequency of oral famotidine administration influences its effect on gastric pH in cats over time

Background

Famotidine is commonly administered to cats. Prolonged famotidine administration results in decreased efficacy in humans, dogs, and cows, but the long‐term effects in cats are unknown.

Objectives

To compare the effect of 2 oral administration frequencies of famotidine, twice daily (Group 1) and twice daily every second day (Group 2), on intragastric pH and serum gastrin concentrations in cats. We hypothesized a diminished effect on intragastric pH would be observed over time in Group 1 but not Group 2.

Animals

Sixteen healthy cats.

Methods

Randomized, 2‐factor repeated measures crossover design. Cats received 0.5‐1.24 mg/kg (median, 0.87 mg/kg) famotidine twice daily or twice daily every second day for 14 consecutive days. Intragastric pH monitoring was used to record intragastric pH on treatment days 1‐3 and 11‐13. Mean pH and mean percentage time (MPT) intragastric pH was ≥3 and 4 were compared between and within treatment groups by analysis of variance.

Results

Significant treatment group by time interactions were observed for mean intragastric pH, MPT intragastric pH ≥3 and 4 (P = .009, P = .02, P = .005, respectively). Interaction post hoc tests identified significant decreases in mean intragastric pH (P = .001), MPT ≥3 (P = .001), and MPT ≥4 (P = .001) on day 13 compared to day 1 in Group 1 but not in Group 2.

Conclusions and Clinical Importance

Oral famotidine administration results in a diminished effect on intragastric pH in healthy cats when given twice daily every day.

ACVIM consensus statement: Support for rational administration of gastrointestinal protectants to dogs and cats

The gastrointestinal (GI) mucosal barrier is continuously exposed to noxious toxins, reactive oxygen species, microbes, and drugs, leading to the development of inflammatory, erosive, and ultimately ulcerative lesions. This report offers a consensus opinion on the rational administration of GI protectants to dogs and cats, with an emphasis on proton pump inhibitors (PPIs), histamine type-2 receptor antagonists (H2 RAs), misoprostol, and sucralfate. These medications decrease gastric acidity or promote mucosal protective mechanisms, transforming the management of dyspepsia, peptic ulceration, and gastroesophageal reflux disease. In contrast to guidelines that have been established in people for the optimal treatment of gastroduodenal ulcers and gastroesophageal reflux disease, effective clinical dosages of antisecretory drugs have not been well established in the dog and cat to date. Similar to the situation in human medicine, practice of inappropriate prescription of acid suppressants is also commonplace in veterinary medicine. This report challenges the dogma and clinical practice of administering GI protectants for the routine management of gastritis, pancreatitis, hepatic disease, and renal disease in dogs and cats lacking additional risk factors for ulceration or concerns for GI bleeding. Judicious use of acid suppressants is warranted considering recent studies that have documented adverse effects of long-term supplementation of PPIs in people and animals.

Retrospective analysis of the effect of acid-suppressant therapy on clinicopathologic parameters of cats with chronic kidney disease

Objectives The aim was to retrospectively evaluate the effects of acid-suppressant therapy in a population of cats with chronic kidney disease (CKD). The study objectives were to evaluate the effects of acid-suppressant therapy on clinicopathologic variables and progression of CKD over time. Methods The databases of two institutions were searched over an 11 year time span for cats fitting inclusion criteria for CKD. A total of 89 cats met the criteria for inclusion and were grouped according to either early (ie, stages 1-2) or advanced (ie, stages 3-4) CKD. Variables were statistically analyzed before and after treatment with either: (1) proton pump inhibitors (PPIs; n = 17), (2) histamine-2 receptor antagonists (H2RAs; n = 30), (3) combined acid-suppressant therapy (PPI + H2RA; n = 6) or (4) no acid-suppressant therapy (n = 36). Shapiro-Wilk testing and Q-Q plots were used to assess normality and variance, respectively. A complete randomized design with a mixed-effects repeated measures ANOVA was used to evaluate for differences in stage, treatment and time, as well as the interaction between these effects. Results A significant increase in blood creatinine concentration was found over time independent of severity of CKD and treatment group ( P = 0.0087). A significant increase in blood sodium concentration (change of 3.12 mmol/l) was found independent of stage in cats receiving PPI therapy ( P = 0.0109). A significant decrease in total blood magnesium (change of 0.15 mmol/l) was detected in two cats with early CKD receiving combined acid suppressants ( P = 0.0025). Conclusions and relevance Results of this retrospective study suggest that cats with CKD receiving PPI therapy may develop alterations in blood sodium concentrations but do not experience more rapid progression of CKD.

Omeprazole Minimally Alters the Fecal Microbial Community in Six Cats: A Pilot Study

Although they have historically been thought of as safe medications, proton pump inhibitors such as omeprazole have been associated with an increased risk of enteric, particularly Clostridium difficile, infections in people. In cats, omeprazole is often the first choice acid suppressant prescribed for the treatment of upper gastrointestinal (GI) ulceration and bleeding. Despite this, no studies to date have explored the effect of omeprazole on the feline fecal microbiome and metabolome. Therefore, the purpose of this pilot study was to evaluate the effect of prolonged omeprazole administration on the fecal microbiome and metabolome in healthy cats to identify targets for analysis in a larger subset of cats with GI disease. A within-subjects, before and after, pilot study was performed whereby six healthy adult cats received 60 days of placebo (250 mg lactose PO q 12 h) followed by 5 mg (0.83–1.6 mg/kg PO q 12 h) omeprazole. On days 0, 30, and 60 of placebo and omeprazole therapy, the fecal microbiome and metabolome were characterized utilizing 16S ribosomal RNA sequencing by Illumina and untargeted mass spectrometry-based methods, respectively. Omeprazole administration resulted in no significant changes in the global microbiome structure or richness. However, transient changes were noted in select bacterial groups with omeprazole administration resulting in an increased sequence percentage of Streptococcus, Lactobacillus, Clostridium, and Faecalibacterium spp. and a decreased sequence percentage of Bifidobacterium spp. Significance was lost for all of these bacterial groups after adjustment for multiple comparisons. The fecal concentration of O-acetylserine and aminomalonate decreased with omeprazole therapy, but significance was lost after adjustment for multiple comparisons. The results of this pilot study conclude that omeprazole has a mild and transient impact on the fecal microbiome and metabolome when orally administered to healthy cats for 60 days. Based on the findings of this pilot study, evaluation of the effect of omeprazole specifically on Streptococcus, Lactobacillus, Clostridium, Faecalibacterium, and Bifidobacterium spp. is warranted in cats with primary GI disease.

Evaluation of Gastric pH and Serum Gastrin Concentrations in Cats with Chronic Kidney Disease

Background

Chronic kidney disease (CKD) is a highly prevalent condition in cats. Advanced CKD is associated with hyporexia and vomiting, which typically are attributed to uremic toxins and gastric hyperacidity. However, gastric pH studies have not been performed in cats with CKD.

Hypothesis/Objectives

To determine if cats with CKD have decreased gastric pH compared to age‐matched, healthy cats. Based on previous work demonstrating an association of hypergastrinemia and CKD, we hypothesized that cats with CKD would have decreased gastric pH compared to healthy, age‐matched control cats.

Animals

10 CKD cats; 9 healthy control cats.

Methods

All cats with concurrent disease were excluded on the basis of history, physical examination, CBC, plasma biochemistry profile, urinalysis, urine culture, serum total thyroxine concentration, and serum symmetric dimethylarginine concentration (controls only) obtained within 24 hours of pH monitoring and assessment of serum gastrin concentrations. Serum for gastrin determination was collected, and 12‐hour continuous gastric pH monitoring was performed in all cats. Serum gastrin concentration, mean pH, and percentage time that gastric pH was strongly acidic (pH <1 and <2) were compared between groups.

Results

No significant differences in serum gastrin concentrations were observed between groups (medians [range]: CKD, 18.7 ng/dL [<10–659.0]; healthy, 54.6 ng/dL [<10–98.0]; P‐value = 0.713) or of any pH parameters including mean ± SD gastric pH (CKD, 1.8 ± 0.5; healthy, 1.6 ± 0.3; P‐value = 0.23).

Conclusions and Clinical Importance

These findings suggest that cats with CKD may not have gastric hyperacidity compared to healthy cats and, therefore, may not need acid suppression. Thus, further studies to determine if there is a benefit to acid suppression in cats with CKD are warranted.

Medical management of gastrinoma in a cat

Case summary

A 7-year-old male castrated domestic short-haired cat was evaluated for a 4 week history of intermittent vomiting, ptyalism, lethargy and weight loss. Serum biochemistry revealed mild mixed hepatopathy. Abdominal ultrasonography identified multiple heterogeneous hepatic masses and a linear, hyperechoic focus with associated reverberation artifact in the wall of the stomach consistent with a gastric ulcer. Serum gastrin concentrations were markedly increased. Cytologic interpretation of a fine-needle aspirate of the hepatic masses was consistent with neuroendocrine neoplasia, and a diagnosis of gastrinoma was established. Deterioration of the cat’s condition, despite at-home acid-suppressant therapy, led to hospitalization. The cat was initially stabilized with intravenous crystalloid fluid therapy, maropitant, pantoprazole and octreotide. A continuous radiotelemetric intragastric pH monitoring system was used to monitor the response of intragastric pH to therapy. Long-term therapy was continued with omeprazole (orally q12h), octreotide (subcutaneously q8h) and thrice-weekly toceranib administered orally. Toceranib therapy led to gastrointestinal upset and was discontinued. Gastric ulceration resolved within 8 weeks, and palliation of clinical signs was achieved for approximately 5 months.

Relevance and novel information

Including this report, only six cases of feline gastrinoma have been reported in the veterinary literature. Little is known regarding non-surgical therapy, and octreotide has not been previously reported for medical management of feline gastrinoma. Results of intragastric pH monitoring and clinical improvement suggest that medical therapy using octreotide and proton pump inhibitors represents a novel therapeutic option for cats with gastrinoma where surgical excision is not feasible.

Prevalence of Gastroesophageal Reflux in Cats During Anesthesia and Effect of Omeprazole on Gastric pH

Background

Gastroesophageal reflux (GER) is poorly characterized in anesthetized cats, but can cause aspiration pneumonia, esophagitis, and esophageal stricture formation.

Objective

To determine whether pre‐anesthetic orally administered omeprazole increases gastric and esophageal pH and increases serum gastrin concentrations in anesthetized cats, and to determine the prevalence of GER using combined multichannel impedance and pH monitoring.

Animals

Twenty‐seven healthy cats undergoing elective dental procedures.

Methods

Prospective, double‐masked, placebo‐controlled, randomized clinical trial. Cats were randomized to receive 2 PO doses of omeprazole (1.45–2.20 mg/kg) or an empty gelatin capsule placebo 18–24 hours and 4 hours before anesthetic induction. Blood for measurement of serum gastrin concentration was collected during anesthetic induction. An esophageal pH/impedance catheter was utilized to continuously measure esophageal pH and detect GER throughout anesthesia.

Results

Mean gastric pH in the cats that received omeprazole was 7.2 ± 0.4 (range, 6.6–7.8) and was significantly higher than the pH in cats that received the placebo 2.8 ± 1.0 (range, 1.3–4.1; P < .001). Omeprazole administration was not associated with a significant increase in serum gastrin concentration (P = .616). Nine of 27 cats (33.3%) had ≥1 episode of GER during anesthesia.

Conclusions and Clinical Relevance

Pre‐anesthetic administration of 2 PO doses of omeprazole at a dosage of 1.45–2.20 mg/kg in cats was associated with a significant increase in gastric and esophageal pH within 24 hours, but was not associated with a significant increase in serum gastrin concentration. Prevalence of reflux events in cats during anesthesia was similar to that of dogs during anesthesia.

Pharmacokinetics and Acid Suppressant Efficacy of Esomeprazole after Intravenous, Oral, and Subcutaneous Administration to Healthy Beagle Dogs

Background

Esomeprazole is an S‐enantiomer of omeprazole that has favorable pharmacokinetics and efficacious acid suppressant properties in humans. However, the pharmacokinetics and effects on intragastric pH of esomeprazole in dogs have not been reported.

Objective

To determine the pharmacokinetics of esomeprazole administered via various routes (PK study) and to investigate the effect of esomeprazole on intragastric pH with a Bravo pH monitoring system (PD study).

Animals

Seven adult male Beagle dogs and 5 adult male Beagle dogs were used for PK and PD study, respectively.

Methods

Both studies used an open, randomized, and crossover design. In the PK study, 7 dogs received intravenous (IV), subcutaneous (SC), and oral doses (PO) of esomeprazole (1 mg/kg). Each treatment period was separated by a washout period of at least 10 days. Esomeprazole plasma concentrations were measured by HPLC/MS/MS. In the efficacy study, intragastric pH was recorded without medication (baseline pH) and following IV, SC, and PO esomeprazole dosing regimens (1 mg/kg) in 5 dogs.

Results

The bioavailability of esomeprazole administered as PO enteric‐coated granules and as SC injections was 71.4 and 106%, respectively. The half‐life was approximately 1 hour. Mean ± SD percent time intragastric pH was ≥3 and ≥4 was 58.9 ± 21.1% and 40.9 ± 17.3% for IV group, 75.8 ± 16.4% and 62.7 ± 17.7% for SC group, 88.2 ± 8.9% and 82.5 ± 7.7% for PO group, and 12.5 ± 3.6% and 3.7 ± 1.8% for baseline. The mean percent time with intragastric pH was ≥3 or ≥4 was significantly increased regardless of the dosing route (P < .05).

Conclusion

The PK parameters for PO and SC esomeprazole administration were favorable, and esomeprazole significantly increased intragastric pH after IV, PO, and SC administration. IV and SC administration of esomeprazole might be useful when PO administration is not possible. No significant adverse effects were observed.

Continuous radiotelemetric monitoring of intragastric pH in a dog with peptic ulceration

CASE DESCRIPTION A 6-year-old castrated male Boxer was evaluated for a 5-week history of frequent vomiting, melena, and signs of abdominal pain following accidental ingestion of 5 to ten 15-mg meloxicam tablets (approx ingested dose, 3.1 to 6.2 mg/kg [1.4 to 2.8 mg/lb]). CLINICAL FINDINGS Clinical signs persisted despite 3 weeks of treatment with sucralfate (41.8 mg/kg [19 mg/lb], PO, q 8 h) and omeprazole (0.8 mg/kg [0.36 mg/lb], PO, q 24 h). Results of a CBC and serum biochemical analysis were unremarkable. Abdominal ultrasonography revealed peptic ulceration, and esophagogastroduodenoscopy confirmed the presence of severe proximal duodenal ulceration. TREATMENT AND OUTCOME A radiotelemetric pH-monitoring capsule was placed in the gastric fundus under endoscopic guidance for continuous at-home monitoring of intragastric pH and response to treatment. Treatment was continued with sucralfate (as previously prescribed) and omeprazole at an increased administration frequency (0.8 mg/kg, PO, q 12 h). Intragastric pH was consistently ≥ 3.0 for > 75% of the day during treatment, with the exception of 1 day when a single dose of omeprazole was inadvertently missed. Ulceration and clinical signs completely resolved. CLINICAL RELEVANCE Continuous radiotelemetric monitoring of intragastric pH in the dog of this report was useful for confirming that treatment achieved a predetermined target pH and for demonstrating the impact of missed doses. Duodenal ulceration resolved with twice-daily but not once-daily omeprazole administration. Findings suggested that twice-daily administration of omeprazole may be necessary to achieve this target pH and that a pH ≥ 3.0 for 75% of the day may promote healing of peptic ulcers in dogs.

Repeated Famotidine Administration Results in a Diminished Effect on Intragastric pH in Dogs

Background

Famotidine is an acid suppressant commonly administered to dogs. Prolonged famotidine use in people results in decreased efficacy, but the effect in dogs is unknown.

Hypothesis/Objectives

To compare the effect of repeated oral administration of famotidine or placebo on intragastric pH and serum gastrin in dogs. We hypothesized that famotidine would have a diminished effect on intragastric pH on day 13 compared to day 1.

Animals

Six healthy adult colony Beagles.

Methods

Randomized, 2‐factor repeated‐measures crossover design. All dogs received oral placebo or 1.0 mg/kg famotidine q12h for 14 consecutive days. Intragastric pH monitoring was used to continuously record intragastric pH on treatment days 1–2 and 12–13. Mean pH as well as mean percentage time (MPT) that intragastric pH was ≥3 or ≥4 were compared between and within groups by analysis of variance. Serum gastrin was measured on days 0, 3, and 12 for each treatment.

Results

Continued administration of famotidine resulted in a significant decrease in mean pH, MPT ≥3, and MPT ≥4 (P < .0001) on day 12 and 13. This resulted in a mean decrease in pH by 1.63 on days 12 and 13 compared to days 1 and 2. Furthermore, a mean decrease of MPT ≥3 and MPT ≥4 by 33 and 45% was observed for the same time period, respectively.

Conclusions and Clinical Importance

Continued administration of famotidine results in a diminished effect on intragastric pH in dogs. Caution is advised when recommending long‐term, daily oral administration of famotidine to dogs.

Gastroduodenal Ulceration in Small Animals: Part 2. Proton Pump Inhibitors and Histamine-2 Receptor Antagonists

In the first part of this review, we discussed the pathophysiology and epidemiology of gastric acid secretion and the epidemiology of gastroduodenal ulceration in dogs and cats. In this section, we discuss the pharmacology and evidence-based clinical use of histamine-2 receptor antagonists and proton pump inhibitors.

A Prospective, Placebo-Controlled Pilot Evaluation of the Effect of Omeprazole on Serum Calcium, Magnesium, Cobalamin, Gastrin Concentrations, and Bone in Cats

BACKGROUND

Chronic proton pump inhibitor administration has been associated with electrolyte and cobalamin deficiency, disrupted bone homeostasis, hypergastrinemia, and rebound acid hypersecretion in humans. It is unknown if this occurs in cats.

OBJECTIVES

Prolonged oral omeprazole results in altered bone mineral density or content, serum calcium, magnesium, cobalamin, and gastrin concentrations in healthy cats.

ANIMALS

Six healthy adult DSH cats.

METHODS

In a within subjects, before and after design, cats received placebo followed by omeprazole (0.83-1.6 mg/kg PO q12h) for 60 days each. Analysis of serum calcium, magnesium, cobalamin, and gastrin concentrations was performed on days 0, 30, and 60. Bone density and content were evaluated on days 0 and 60 of each intervention. Continuous data were analyzed using a two-way ANOVA (α = 0.006). On day 60 of omeprazole administration, continuous intragastric pH monitoring was performed in 2 cats to evaluate the effects of abrupt withdrawal of omeprazole.

RESULTS

No significant changes were detected between treatments for any variables, except serum gastrin, which was significantly higher during omeprazole treatment in comparison to placebo (P = 0.002). Evidence of gastric hyperacidity was seen in both cats in which intragastric pH monitoring was performed following cessation of omeprazole.

CONCLUSIONS AND CLINICAL IMPORTANCE

Although further studies with larger populations of cats will be needed to draw any definitive conclusions, these preliminary results suggest that prolonged PPI treatment results in hypergastrinemia and abrupt PPI withdrawal might result in RAH in cats.

ISFM Consensus Guidelines on the Diagnosis and Management of Feline Chronic Kidney Disease

PRACTICAL RELEVANCE

Chronic kidney disease (CKD) is one of the most commonly diagnosed diseases in older cats. In most cats, CKD is also a progressive disease and can be accompanied by a wide range of clinical and clinicopathological changes. These ISFM Consensus Guidelines have been developed by an independent panel of clinicians and academics to provide practical advice on the diagnosis and management of this complex disease.

CLINICAL CHALLENGES

Although CKD is a common clinical problem in cats, the manifestations of disease vary between individuals. Thus there is a need for careful and repeat evaluation of cats with CKD and adjustment of therapy according to individual needs. In addition to addressing problems arising from CKD and improving quality of life (QoL) for the patient, therapy may also target slowing the underlying progression of disease and hence prolonging life. While maintaining QoL is of paramount importance in our patients, this can be challenging when multiple therapies are indicated. In some cases it is necessary to prioritise therapy, given an understanding of what is likely to most benefit the individual patient.

EVIDENCE BASE

In preparing these Guidelines, the Panel has carefully reviewed the existing published literature, and has also graded the quality of evidence for different interventions to help to provide practical recommendations on the therapeutic options for feline CKD. This is a field of veterinary medicine that has benefited from some excellent published clinical research and further research findings will undoubtedly modify the recommendations contained in these Guidelines in the future.

The effect of orally administered ranitidine and once-daily or twice-daily orally administered omeprazole on intragastric pH in cats

BACKGROUND

Gastric acid suppressants frequently are used in cats with acid-related gastric disorders. However, it is not known if these drugs effectively increase intragastric pH in cats.

OBJECTIVES

To examine the effects of PO administered ranitidine and omeprazole on intragastric pH in cats and to compare the efficacy of once-daily versus twice-daily dosage regimens for omeprazole.

ANIMALS

Eight domestic shorthair cats.

METHODS

Using a randomized 4-way cross-over design, cats were given enteric-coated omeprazole granules (1.1-1.3 mg/kg q24h and q12h), ranitidine (1.5-2.3 mg/kg q12h), and placebo. Intragastric pH was monitored continuously for 96 hours using the Bravo(™) system, starting on day 4 of treatment, followed by a median washout period of 12 days. Mean percentage of time pH was ≥3 and ≥4 was compared among groups using repeated measures ANOVA.

RESULTS

Mean ± SD percentage of time intragastric pH was ≥3 and ≥4 was 67.0 ± 24.0% and 54.6 ± 26.4% for twice-daily omeprazole, 24.4 ± 22.8% and 16.8 ± 19.3% for once-daily omeprazole, 16.5 ± 9.0% and 9.6 ± 5.9% for ranitidine, and 9.4 ± 8.0% and 7.0 ± 6.6% for placebo administration. Twice-daily omeprazole treatment significantly increased intragastric pH, whereas pH after once-daily omeprazole and ranitidine treatments did not differ from that of placebo-treated cats.

CONCLUSION AND CLINICAL IMPORTANCE

Only twice-daily PO administered omeprazole significantly suppressed gastric acidity in healthy cats, whereas once-daily omeprazole and standard dosages of ranitidine were not effective acid suppressants in cats.