Parenteral control of gastric acid hypersecretion in patients with Zollinger-Ellison syndrome

Parenteral control of gastric acid hypersecretion in patients with Zollinger-Ellison syndrome is increasingly required; however, existing methods of determining the required dose are cumbersome and not applicable in all centers. A previous study suggested that the required parenteral dose of histamine H₂-receptor antagonists correlated with the previous oral dose. In the present study, in 31 patients with Zollinger-Ellison syndrome we evaluated the hypothesis that an effective parenteral histamine H₂-receptor antagonist dose could be predicted from the previous oral dose. Twenty-three patients were taking oral ranitidine (mean 1.3 g/day), six patients famotidine (152 mg/day), and two patients cimetidine (1.8 g/day). Each patient was treated with a continuous intravenous infusion of the equivalent dose of ranitidine (mean dose 1 mg/kg/hr with 35% requiring 0.5 mg/kg/hr, 49% 1 mg/kg/hr, 3% 1.5 mg/kg/hr, 10% 2 mg/kg/hr, and 3% 2.5 mg/kg/hr. This dose of ranitidine acutely controlled acid secretion (<10 meq/hr) in all patients. To evaluate long-term efficacy and safety, 20 patients were maintained on this dose through the peri-and postoperative periods. Mean duration was 7.1 days with 25% treated 3–5 days, 40% 6–8 days, 30% 8–10 days, and 5%>10 days. The predicted dose continued to control acid secretion in 95% of patients with one patient requiring one dose adjustment. No biochemical, clinical, or hematological toxicity was seen, although ranitidine was stopped in one patient because of skin rash. These results demonstrate that the parenteral dose of ranitidine required to control acid secretion in patients with Zollinger-Ellison syndrome can be predicted from the oral dose. This predicted dose will be acutely effective in all patients in reducing acid secretion to <10 meq/hr, the established level of control, will remain effective in 95% of patients for up to 11 days, and is safe. By utilizing the oral dose to predict the intravenous dose, repeated dose titrations will be avoided and thus this method should be generally useful in all settings.     

Intravenous pantoprazole rapidly controls gastric acid hypersecretion in patients with Zollinger-Ellison syndrome

BACKGROUND & AIMS: Parenteral control of gastric acid hypersecretion in conditions such as Zollinger-Ellison syndrome (ZES) or idiopathic gastric acid hypersecretion is necessary perioperatively or when oral medications cannot be taken for other reasons (e.g., during chemotherapy, acute upper gastrointestinal bleeding, or in intensive care unit settings). METHODS: We evaluated the efficacy and safety of 15-minute infusions of the proton pump inhibitor pantoprazole (80-120 mg every 8-12 hours) in controlling acid output for up to 7 days. Effective control was defined as acid output >10 milliequivalents per hour (mEq/h) (<5 mEq/h in patients with prior acid-reducing surgery) for 24 hours. RESULTS: The 21 patients enrolled had a mean age of 51.9 years (range, 29-75) and a mean disease duration of 8.1 years (range, <0.5-21); 13 were male, 7 had multiple endocrine neoplasia syndrome type I, 4 had undergone acid-reducing surgery, 2 had received chemotherapy, and 13 had undergone gastrinoma resections without cure. Basal acid output (mean +/- SD) was 40.2 +/- 27.9 mEq/h (range, 11.2-117.9). In all patients, acid output was controlled within the first hour (mean onset of effective control, 41 minutes) after an initial 80-mg intravenous pantoprazole dose. Pantoprazole, 80 mg every 12 hours, was effective in 17 of 21 patients (81%) for up to 7 days. Four patients required upward dose titration, 2 required 120 mg pantoprazole every 12 hours, and 2 required 80 mg every 8 hours. At study end, acid output remained controlled for 6 hours beyond the next expected dose in 71% of patients (n = 15); mean acid output increased to 4.0 mEq/h (range, 0-9.7). No serious or unexpected adverse events were observed. CONCLUSIONS: Intravenous pantoprazole, 160-240 mg/day administered in divided doses by 15-minute infusion, rapidly and effectively controlled acid output within 1 hour and maintained control for up to 7 days in all ZES patients.     

Physiologic responses to gastric acid hypersecretion in Zollinger-Ellison syndrome

Summary Two patients with gastric acid hypersecretion and intact stomachs had diarrhea with steatorrhea. In 1 patient continuous outpouring of large volumes of alkaline juice into the duodenum, combined with the buffering capacity of food, resulted in normal or near normal pH levels in the upper small intestine for at least 90 min. after a meal. The tryptic activities in intestinal aspirates after the meal were essentially normal. Watery diarrhea was controlled when an anticholinergic drug was given both night and day, but steatorrhea was not reduced. In the other patient the alkaline secretions of the upper intestine were inadequate to neutralize the gastric acid output. The mechanisms by which acid secreted by the stomach is neutralized in the upper small bowel and the mechanisms of diarrhea are discussed.Supported by Grants FR-42 from the Division of Research Facilities and Resources and AM-07120 from the National Institute for Arthritis and Metabolism, U. S. Public Health Service.We wish to thank Dr. F. Avery Jones for allowing us to publish Case 2, and Professor R. A. Gregory for examining the tumors.     

Recent advances in the management of gastric acid hypersecretion in patients with Zollinger-Ellison syndrome

Several histamine H2 receptor antagonists and the H+,K(+)-ATPase inhibitor, omeprazole, have been shown to be capable of controlling gastric acid secretion safely and effectively in patients with Zollinger-Ellison syndrome. The relative merits of these agents are discussed, and their use in the acute and long-term control of acid hypersecretion and in special circumstances that require particular care are described. The surgical approaches to the control of acid secretion are described, and the current place of surgery in the management of acid hypersecretion is discussed.     

Ranitidine therapy in patients with idiopathic gastric acid hypersecretion

One hundred twenty-four patients with idiopathic gastric acid hypersecretion (basal acid output greater than 10.0 meq/hr) were prospectively evaluated and treated with ranitidine twice a day. Fifty-four patients (44%) required standard doses of ranitidine 300 mg/day for adequate treatment, and the other 70 patients (56%) required increased doses of ranitidine (mean 994 mg/day, range 600–3000 mg/day). Mean basal acid outputs for these two groups were 14.0 and 16.6 meq/hr, respectively, which were not significantly different. Nevertheless, there was a significant correlation between basal acid output and daily ranitidine dose required for therapy (r=0.18,P=0.05). The duration of ranitidine therapy consisted of: <1 year (N=46), 1 year (N=16), 2 years (N=19), 3 years (N=22), 4 years (N=15), 5 years (N=6). Only five patients required progressive increases in ranitidine during the time of treatment, which consisted of an average of 0.5 dose adjustments per year. No side effects occurred with any of these high doses of ranitidine. These results indicate that, as in Zollinger-Ellison syndrome, ranitidine is effective therapy for patients with idiopathic gastric acid hypersecretion; however, markedly increased doses as large as 3000 mg/day may be required.     

Recklinghausen's disease with digestive localizations associated with gastric acid hypersecretion suggesting Zollinger-Ellison syndrome

We report the case of a 49 year old male patient who had Recklinghausen's disease associated with hyperchlorhydria. The principal features of Recklinghausen's disease were cutaneous localizations and countless digestive tumors, found mainly on the small bowel. The ultrastructural aspect of these tumors was neurinoma or schwannoma. Basal acid gastric hypersecretion and a positive secretin test were highly suggestive of a Zollinger-Ellison syndrome. Gastrinoma was not found at laparotomy even though a gastrin gradient had been demonstrated by pancreatic venous sampling. In a patient with Recklinghausen's disease, neuroendocrine tumors (APUDomas) should be looked for systematically.     

Thyrotropin-releasing hormone suppressed gastric acid output in patients with Zollinger-Ellison syndrome and systemic mastocytosis

Thyrotropin-releasing hormone administered intravenously was found to be as potent an inhibitor of gastric acid secretion as a conventional dose of oral cimetidine in two patients with Zollinger-Ellison syndrome and one patient with systemic mastocytosis.     

Maintenance oral pantoprazole therapy is effective for patients with Zollinger-Ellison syndrome and idiopathic hypersecretion

OBJECTIVE: Maintenance proton pump inhibitor (PPI) therapy is effective for gastric acid hypersecretory states, although data with pantoprazole are limited. The aim of this study was to evaluate the safety and efficacy of long term p.o. pantoprazole in individuals with hypersecretion. METHODS: All subjects had Zollinger-Ellison syndrome or idiopathic hypersecretion. Baseline acid output was measured in the presence of prior maintenance antisecretory therapy before pantoprazole exposure. The starting dose was 40 mg b.i.d. in most cases, and the dose was adjusted to document control within the first 2 wk of therapy. The maximal allowable dose was 240 mg daily. Acid output was measured on day 28 and then quarterly from month 3. The primary efficacy endpoint was documented control of acid secretion at 6 months, i.e., acid output in the last 1 h before the next dose of therapy of <10 mEq/h (<5 mEq/h in subjects with prior acid-reducing surgery). RESULTS: A total of 26 subjects had Zollinger-Ellison syndrome (six with multiple endocrine neoplasia syndrome type 1) and nine had idiopathic hypersecretion. Pre-enrollment therapy included omeprazole in 27 subjects and lansoprazole in eight, and 82.4% of subjects were controlled on their prior regimens. With upward dose titration, acid output was controlled in all subjects by day 10 and in all but two (6%) at the 6-month time point. Median acid secretion on therapy at 6 months was <2 mEq/h (mean 2.2 mEq/h; range 0-10.5 mEq/h) at a dose of 40 mg b.i.d. for 24 subjects, 80 mg b.i.d. for seven subjects, and 120 mg b.i.d. for two subjects. During the course of the study, five subjects required doses of 240 mg daily. Pantoprazole was generally well tolerated. No cases of anterior optic ischemic neuropathy occurred. Five subjects died during follow-up, all because of events unrelated to the study drug. CONCLUSIONS: Maintenance p.o. pantoprazole therapy at a dose of 80-240 mg/day in divided doses was both effective and generally well tolerated for patients with Zollinger-Ellison syndrome and idiopathic hypersecretion.     

Helicobacter pylori in duodenal ulcer patients with idiopathic gastric acid hypersecretion

Thirty-three consecutive patients with idiopathic gastric acid hypersecretion (defined as a basal acid output >10.0 meq/hr with a normal fasting serum gastrin level and negative secretin stimulation test) who were being treated for duodenal ulcer disease and other acid-peptic disorders were evaluated for the presence ofHelicobacter pylori by means of a rapid urease test. Fourteen patients had duodenal ulcer and 19 had other acid-peptic disorders (gastroesophageal reflux in 14, including six with Barrett's esophagus; four with nonulcer dyspepsia; and one with erosive gastritis).Helicobacter pylori was present in 12 of the 14 ulcer patients (86%) compared to only two of the 19 nonulcer patients (11%) (P<0.0001). The distribution of basal acid output for patients with duodenal ulcer was similar to that for nonulcer patients, and no significant difference in the mean basal acid output was found amongHelicobacter pylori-positive compared toHelicobacter pylori-negative patients. Seven of the duodenal ulcer patients with a basal acid output greater than 15.0 meq/hr wereHelicobacter pylori-positive, suggesting that the organism can withstand even extreme levels of gastric acidity. In conclusion, this study demonstrates that the prevalence ofHelicobacter pylori infection in patients with duodenal ulcer disease associated with idiopathic gastric acid hypersecretion is not different from a majority of ulcer patients with normal acid secretory profiles and offers additional evidence that extreme levels of gastric acid are not bactericidal for the organism.     

Replacement of oral proton pump inhibitors with intravenous pantoprazole to effectively control gastric acid hypersecretion in patients with Zollinger-Ellison syndrome

OBJECTIVES: In patients with Zollinger-Ellison syndrome (ZES) or other conditions requiring oral doses of proton pump inhibitors, it frequently becomes necessary to use parenterally administered gastric acid inhibitors. However, i.v. histamine-2 receptor antagonists are not effective at usual doses and lose their effectiveness because of tachyphlaxis. With the approval in the United States of i.v. pantoprazole, a substituted benzimidazole available in i.v. formulation, it will become possible to acutely manage gastric acid secretion in the acute care setting of a hospital. This study was developed to monitor the safety and establish the efficacy of i.v. pantoprazole as an alternative to oral proton pump inhibitors for the control of gastric acid hypersecretion in patients with ZES. METHODS: The efficacy of replacing oral PPI therapy with i.v. pantoprazole was evaluated in 14 ZES patients. After study enrollment, patients taking their current doses of oral PPI (omeprazole or lansoprazole) were switched to pantoprazole i.v. for 6 days during an 8-day inpatient period in the clinical research center. Effective control was defined as an acid output (AO) of < 10 mEq/h (< 5 mEq/h in patients with prior gastric acid-reducing surgery). RESULTS: The mean age of the 14 patients enrolled in the study was 52.4 yr (range = 38-67). Mean basal AO was 0.55 +/- 0.32 mEq/h and mean fasting gastrin was 1089 pg/ml (range = 36-3720). Four patients were also diagnosed with the multiple endocrine neoplasia type I syndrome, nine were male, and two had previously undergone acid-reducing surgery. Before study enrollment, gastric acid hypersecretion was controlled in nine of 14 patients with omeprazole (20-200 mg daily) and five of 14 with lansoprazole (30-210 mg daily). In the oral phase of the study all patients had adequate control of gastric acid secretion, with a mean AO of 0.55 +/- 0.32 mEq/h (mean +/- SEM). Thereafter, 80 mg of i.v. pantoprazole was administered b.i.d. for 7 days by a brief (15 min) infusion and the dose was titrated upward to a predetermined maximum of 240 mg/24 h to control AO. A dose of 80 mg b.i.d. of i.v. pantoprazole controlled AO in 13 of 14 of the patients (93%) for the duration of the study (p > 0.05 compared to baseline values for all timepoints). One sporadic ZES patient (oral control value = 0.65 mEq/h on 100 mg of omeprazole b.i.d. p.o.) was not controlled with 80 mg of i.v. pantoprazole b.i.d. and dosage was titrated upward to 120 mg b.i.d. after day 2. CONCLUSIONS: There were no serious adverse events observed. Intravenous pantoprazole provides gastric acid secretory control that is equivalent to the acid suppression observed with oral proton pump inhibitors. Most ZES patients (93%) maintained effective control of AO previously established with oral PPIs when switched to 80 mg of i.v. pantoprazole b.i.d.; however, for difficult-to-control patients, doses > 80 mg b.i.d. may be required.     

Definition for idiopathic gastric acid hypersecretion

Zollinger-Ellison syndrome and other gastric acid hypersecretory states in which a specific etiology is identified are defined as a basal acid output of greater than 15.0 meq/hr. To determine the level of basal acid output that defines idiopathic gastric hypersecretion, basal acid outputs were investigated in normal subjects and patients with duodenal ulcers, and functional and statistical definitions for idiopathic gastric acid hypersecretion were developed. Sixty-five normal subjects were evaluated to define idiopathic gastric acid hypersecretion on a statistical basis, and 22 patients with refractory duodenal ulcers were evaluated to define idiopathic gastric acid hypersecretion on a functional basis. Mean basal acid output for the 65 normal subjects was 3.0±2.7 meq/hr. Even though the mean basal acid output for the group of 28 normal male subjects was slightly higher than for the group of 37 normal female subjects, the groups were not significantly different. The 95% confidence interval around the mean basal acid output for all normal subjects was 2.4–3.7 meq/hr, with little difference between the male and female groups. The mean basal acid output plus two standard deviations and the mean basal acid output plus three standard deviations for the 65 normal subjects were 8.4 meq/hr and 11.1 meq/hr, respectively. Of 109 patients with active duodenal ulcers treated for eight weeks with standard doses of antisecretory medication, 22 showed no healing as documented by endoscopy. The mean basal acid output for these 22 patients with nonhealed duodenal ulcers was 18.7 meq/hr (range 10.1–49.1 meq/hr) while mean basal acid output for the 87 patients with healed duodenal ulcers was 7.5 meq/hr (range 0.0–27.9 meq/hr). The difference in mean basal acid output between these two groups was statistically different (P<0.001). All patients with refractory duodenal ulcers had basal acid outputs of greater than 10.0 meq/hr. Our results indicate that the definition for idiopathic gastric acid hypersecretion should be a basal acid output of greater than 10.0 meq/hr, since, based on refractory duodenal ulcer disease, the functional definition for idiopathic gastric acid hypersecretion is a basal acid output of greater than 10.0 meq/hr, which in our data also corresponds well to the statistically defined range of basal acid output in normal subjects.     

Effect of sham feeding on acid secretion in patients with Zollinger-Ellison syndrome with or without proximal gastric vagotomy

In dogs, vagal stimulation by sham feeding inhibits gastrin-stimulated gastric acid secretion from vagally denervated fundic pouches. To investigate this in humans, we sham fed patients with endogenous hypergastrinemia secondary to the Zollinger-Ellison syndrome. Whether these patients had been treated previously by proximal gastric vagotomy or not, sham feeding did not reduce basal acid secretion. Thus, sham feeding did not inhibit acid secretion in humans with hypergastrinemia, even when the fundus of the stomach had been vagally denervated.     

Treatment of gastric acid hypersecretion in the Zollinger-Ellison syndrome with a thioamide derivative (40749 RP). Comparison with ranitidine

The efficacy of a new gastric antisecretory drug, 40749 RP, was studied in five cases of Zollinger-Ellison syndrome. Daily oral dosage was 2 mg/kg bw b.d. Clinical results and tolerance were excellent in all five cases (follow-up 1 to 16 months). In two cases, chronic duodenitis disappeared with 40749 RP only. Antisecretory activity was evaluated on basal acid output and 24 h pH profile. During 24 h period, the mean number of hours at or below pH 1.5, 2 and 3 obtained with 40749 RP in the five cases was 5, 9 and 12 h versus 13, 14 and 19 h with ranitidine. In all cases, basal acid output measured during one hour before fractional intake of 40749 RP was below 7 mmol/h during the first month of treatment. Clinical and biological results obtained with 40749 RP are similar to those obtained with omeprazole.     

Basal acid output and gastric acid hypersecretion in gastroesophageal reflux disease

The purpose of this study was to evaluate possible differences in basal gastric acid secretion with regard to severity of gastroesophageal reflux disease. Basal acid output was determined by nasogastric suction in 228 patients with gastroesophageal reflux disease who received upper gastrointestinal endoscopy and were diagnosed with either pyrosis alone (N = 98), erosive esophagitis with or without pyrosis (N = 87), or Barrett's esophagus (N = 43). Mean basal acid output for the 228 patients with gastroesophageal reflux disease was 6.5 ± 5.6 meq/hr, which was significantly different from 65 normal subjects with a mean basal acid output of 3.0 ± 2.7 meq/hr (P < 0.0001). Compared to normal subjects, mean basal acid outputs significantly differed for patients with pyrosis (P < 0.05), esophagitis (P < 0.01), and Barrett's esophagus (P < 0.01). There was also a significant difference in mean basal acid output between the patients with pyrosis and Barrett's esophagus (P < 0.01). Nineteen of the 98 patients with pyrosis (19%), 24 of the 87 patients with esophagitis (28%), and 15 of the 43 patients with Barrett's esophagus (35%) had gastric acid hypersecretion (basal acid output greater than 10.0 meq/hr). One hundred forty-six patients with gastroesophageal reflux disease were treated with ranitidine in doses that resulted in complete healing of esophagitis and disappearance of pyrosis. Ninety-three patients responded to ranitidine 300 mg/day; however, 53 patients required increased dose of ranitidine (mean 1205 mg/day, range 600–3000 mg/day). There was a significant correlation between basal acid output and daily ranitidine dose required for therapy for the 146 patients with gastroesophageal reflux disease (r = 0.53,P = 0.0001). Furthermore, a significant association was also found between the presence of gastric acid hypersecretion and the requirement for increased doses of ranitidine (greater than 300 mg/day) (P = 0.00001). These results indicate that there is a subset of patients with gastroesophageal reflux disease who do have idiopathic gastric acid hypersecretion. Moreover, these patients have an apparently higher requirement for medication dosage in order to achieve therapeutic efficacy.     

Idiopathic gastric acid hypersecretion presenting as a diarrheal disorder and mimicking both Zollinger-Ellison syndrome and Crohn's disease

Many gastric acid hypersecretory states (basal acid output of greater than 15.0 mEq/h) exist for which the etiology is known, such as Zollinger-Ellison syndrome, systemic mastocytosis, antral exclusion, antral predominant Helicobacter pylori gastritis (antral G cell hyperplasia), chronic gastric outlet obstruction, short gut syndrome and basophilic leukemias. However, many hypersecretory patients have no identified etiology for their acid hypersecretion and are designated as idiopathic gastric acid hypersecretors with a basal acid output of greater than 10 mEq/h and a normal serum gastrin level. Because of the gastric acid hypersecretion these patients also commonly have an increased frequency of stools. Idiopathic gastric acid hypersecretion represents a known cause of gastric acid hypersecretion that is far more common than Zollinger-Ellison syndrome and it has a markedly different treatment regimen and natural history. We report a case of a patient with idiopathic gastric acid hypersecretion previously misdiagnosed as having Crohn's disease because of a presenting complaint of diarrhea and mimicking Zollinger-Ellison syndrome because her fasting serum gastrin level was elevated when incorrectly measured in the presence of antisecretory treatment.     

Reliability of symptoms in assessing control of gastric acid secretion in patients with Zollinger-Ellison syndrome

In the present study we explored whether the presence or absence of symptoms could provide a reliable way of assessing the adequacy of control of gastric secretion in patients with Zollinger-Ellison syndrome who were treated medically. Over a 5-yr period, 26 Zollinger-Ellison syndrome patients were entered into a prospective study which examined the presence or absence of symptoms that are associated with gastric hypersecretion, the presence of absence of upper gastrointestinal pathology, and the degree of control of gastric acid secretion. During their last admission, 15 of the 26 patients (58%) were symptomatic, but post-drug gastric acid secretion for the 2 h before the next dose of medication was not significantly different from that in asymptomatic patients. This lack of correlation between the presence or absence of symptoms and post-drug gastric acid secretion was evident for the group as a whole, as well as for 8 to 12 patients who underwent multiple admissions. Of 23 patients who underwent upper gastrointestinal endoscopy of x-ray, or both, on their last admission, 12 had pathology. Post-drug gastric acid secretion was less in patients without pathology than in those with pathology. Furthermore, in patients in whom post-drug gastric acid secretion was less than or equal to 10 mEq/h, the criterion of acceptable control used in this study, pathology did not occur. These findings demonstrate that the presence or absence of symptoms cannot be used to assess the adequacy of medical control of gastric acid secretion in patients with Zollinger-Ellison syndrome. In our opinion, maintenance of post-drug gastric acid secretion less than or equal to 10 mEq/h for the 2 h before the next dose of medication is an acceptable criterion for long-term control of gastric secretion in patients with Zollinger-Ellison syndrome.