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.

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.

Review article: pharmacokinetic concerns in the selection of anti-ulcer therapy.

Rabeprazole is a new, highly potent proton pump inhibitor (PPI) being introduced for the treatment of disorders of gastric acid hypersecretion. Rabeprazole joins other drugs in this class, such as omeprazole, pantoprazole, and lansoprazole, which share a common mechanism of action. Each of these drugs is a substituted benzimidazole, which inhibits activity of the H+, K+ -ATPase located on the apical surface of parietal cells, thereby preventing the secretion of gastric acid. As a result of structural and functional similarities, the PPIs share many pharmacokinetic features. They have comparable rates of absorption, maximum plasma concentrations, and total drug absorptions resulting in similar bioavailability after single-dose administration. With multiple dosing, rabeprazole differs from omeprazole in that its pharmacokinetic profile does not change significantly over the course of therapy. All the PPIs are metabolized rapidly, resulting in short half-lives. However, their duration of activity is much longer, due to the way in which they bind to H+, K+ -ATPase. All are metabolized by hepatic cytochrome P450 enzymes, although only omeprazole has demonstrated significant interactions with other drugs metabolized by this pathway. Rabeprazole, which has a low potential for interacting with drugs metabolized by cytochrome P450, does interfere with the absorption of digoxin and ketoconazole because of its antisecretory effects. The pharmacokinetics of rabeprazole are altered slightly in elderly subjects and in patients with renal and moderate hepatic disease. However, the pharmacokinetic findings suggest that no dosage adjustment is required in these special populations.

Adenocarcinoma of the colon with neuroendocrine features and secretory diarrhea.

We report the case of a 63-yr-old man who had severe secretory diarrhea associated with colonic adenocarcinoma, with a prominent signet ring cell component and numerous endocrine cells as demonstrated by positive chromogranin-A staining. Improvement in the secretory diarrhea by the somatostatin analog Sandostatin suggested that the diarrhea was related to a functional neuroendocrine tumor within the colonic tumor, the first case to be reported in the literature.

An ascending single-dose safety and tolerance study of an oral formulation of rabeprazole (E3810).

BACKGROUND: Proton pump inhibitors such as omeprazole produce a long-lasting inhibition of gastric acid secretion associated with significant increases in plasma gastrin. Rabeprazole (E3810) is a new substituted benzimidazole H+,K+ ATPase inhibitor. It acts as an irreversible, non-competitive inhibitor of the H+,K+ ATPase and preliminary studies demonstrate that rabeprazole produces a potent and long-lasting inhibition of gastric acid secretion and a low level of hypergastrinaemia. AIM: This randomized, double-blind, placebo-controlled study was performed to further examine the effects of different single doses of rabeprazole on gastric acid secretion and serum gastrin. METHODS: In this study, four groups of 10 healthy, non-smoking Helicobacter pylori-negative men (mean age 22.5 +/- 3.9 years) received single oral doses of 10, 20, 30 and 40 mg of rabeprazole. Two of the 10 volunteers in each group received placebo as part of the double-blind study design. All volunteers who entered into the study had a normal gastric acid secretory capacity as evaluated by pentagastrin challenge. Prior to administration of the first dose of test drug, volunteers underwent an inpatient 24-h measurement of baseline intragastric pH. One week later, volunteers received the test drug and again underwent an inpatient 24-h measurement of intragastric pH. During both periods, plasma samples were collected at specified intervals over 48 h and were sent for analysis of rabeprazole and gastrin levels. RESULTS: Administration of rabeprazole resulted in a dose-dependent increase in the duration and extent of intragastric pH elevation. The response among all volunteers receiving drug was significantly different from placebo, with greater acid inhibition occurring in the 30 and 40 mg groups. In addition, there was also a dose-related increase in plasma gastrin. The pharmacokinetics of rabeprazole were similar to those of other proton pump inhibitors with a t1/2 of between 0.7 and 1.0 h. There were no clinically significant effects on patient laboratory tests or serious adverse events. CONCLUSIONS: The results of this study suggest that rabeprazole is as potent as omeprazole and lansoprazole in inhibiting gastric acid secretion.

Treatment of gastrointestinal cytomegalovirus infection with twice-daily foscarnet: a pilot study of safety, efficacy, and pharmacokinetics in patients with AIDS.

Ten patients with AIDS and cytomegalovirus (CMV) gastrointestinal infection were included in an open-label study to evaluate the safety, efficacy, and pharmacokinetics of 90 mg of intravenous foscarnet/kg of body weight twice daily accompanied by (pre)hydration of 500 to 750 ml. Efficacy was documented endoscopically, while safety was evaluated clinically by patient reports and physical and laboratory observation. The pharmacokinetics of foscarnet was evaluated after the first dose and following approximately 20 days of therapy. Nine patients (90%) responded histopathologically, nine (90%) responded endoscopically, and nine (90%) responded symptomatically to foscarnet therapy. Adverse events resulted in discontinuance of medication in the case of one patient. The mean maximal concentration was 621 microM following the first dose and 687 microM at steady state (P = 0.11). The apparent elimination rate constant and elimination half-life were not different between dose 1 and steady state. There were no significant changes in foscarnet excretion or renal clearance between dose 1 and steady state. The steady-state volume of distribution was 23.4 liters following the first dose and 19.0 liters at steady state (P < 0.002). Twice-daily foscarnet appeared to be safe and efficacious in the treatment of CMV gastrointestinal disease in this study, resulting in endoscopic or histologic improvement in 9 of the 10 (90%) patients. Minor changes in clearance and volume of distribution noted at steady state compared to single-dose administration are readily explained by study design, known information about foscarnet pharmacokinetics, and changes in body weight and creatinine clearance in the patients.

Diarrheal diseases associated with HIV infection.

Diarrhea is a major complication of HIV infection and adversely impacts health care costs, quality of life, and even survival of patients. There is a wide variety of potential causes of diarrhea in HIV-infected patients, and the number of pathogens found continues to increase with time. In addition, there is some controversy concerning the role of some organisms in the pathogenesis of diarrhea and the appropriate diagnostic evaluation of affected patients. This article reviews our current understanding of these pathogens and some of the diagnostic and therapeutic approaches for diarrhea associated with HIV infection.

Diagnosis and treatment of hepatic disease in patients with HIV.

Liver involvement with opportunistic infections and neoplasms is a well-recognized component of AIDS, affecting most patients. The cause of hepatic disease in these patients may be divided into hepatitis, granulomatous disease, mass lesions, vascular lesions, hepatotoxic drugs, and nonspecific findings. With a rational approach, most patients with AIDS and liver disease can be diagnosed and treated in a cost-effective manner with low morbidity.

Liver biopsy findings in 501 patients infected with human immunodeficiency virus (HIV).

Patients infected with human immunodeficiency virus (HIV) are at risk for a variety of liver diseases. We undertook a retrospective study of 501 HIV-seropositive patients to assess the yield of percutaneous liver biopsy. The most common indications for liver biopsy were liver test abnormalities (89.5%), fever for 2 weeks (71.9%), and hepatomegaly (52.0%). The most common biopsy-derived diagnosis was Mycobacterium avium complex (MAC), seen in 87 (17.4%) biopsies. Mycobacterium tuberculosis was found in 13 biopsies (2.6%). In 28 biopsies (5.6%) mycobacteria was seen, but speciation of the organism was not possible. Chronic active viral hepatitis was seen in 60 biopsies (12.0%). Opportunistic hepatic infection from other organisms was found in 14 biopsies (2.8%). The most common neoplasm was lymphoma, which was seen in 12 biopsies (2.4%). MAC infection of the liver was associated with elevated alkaline phosphatase (p = 0.01). Among patients with fever for 2 weeks after an extensive negative workup including bone marrow biopsy, 58.2% had a diagnosis by liver biopsy. Overall, 64.3% of liver biopsies yielded a histopathological diagnosis, 45.7% of which were potentially treatable. We could not evaluate whether liver biopsy had a positive effect on patient outcome and survival, nor did we attempt to prove that liver biopsy resulted in a change in treatment or a change in preprocedure clinical diagnosis. Thus, questions about the efficacy of liver biopsy cannot be answered. Liver biopsy may be a helpful diagnostic tool in HIV-positive patients with fever, liver test abnormalities or hepatomegaly.

Treatment with albendazole for intestinal disease due to Enterocytozoon bieneusi in patients with AIDS.

To determine the efficacy and safety of albendazole for treatment of intestinal microsporidosis due to Enterocytozoon bieneusi, 29 patients with AIDS were studied. All had chronic diarrhea, weight loss, and evidence of malabsorption. After 1 month of treatment with albendazole (400 mg orally twice a day), the mean number of bowel movements decreased from 7.0 to 3.8 stools/day (P < .0001) and the mean weight gain was 0.56 kg (P = .259). Albendazole at this dose did not clear E. bieneusi on follow-up small-bowel biopsies, but ultrastructural studies revealed an apparent decrease in parasite burden in 2 patients and an increased proportion of dividing plasmodia in 5 patients. There were no significant adverse events associated with this dose of albendazole. A formal double-blind placebo-controlled study using higher doses has recently been approved and will soon be underway (AIDS Clinical Trial Group protocol 207).

Concurrent use of ganciclovir and foscarnet to treat cytomegalovirus infection in AIDS patients.

Ten patients with AIDS and progressive cytomegalovirus disease were treated with ganciclovir and foscarnet concurrently. The patients had received ganciclovir and foscarnet monotherapy a median of 330 days before receiving combination therapy for a median of 80 days. Nine of the 10 patients responded to the combination. No electrolyte abnormalities were noted during combination therapy, but rates of neutropenia (relative rate, combination vs. ganciclovir, 1.99; P = .229) and thrombocytopenia (relative rate, combination vs. ganciclovir, 1.53; P = .616) were higher with combination therapy than with either drug alone. The relative rate of anemia was significantly increased with combination therapy compared with monotherapy (relative rate, combination vs. ganciclovir, 2.69; P = .025). These data suggest that combination ganciclovir and foscarnet therapy after failure of either alone appears to be as effective as standard therapy with single agents. The rate of anemia with combination therapy was significantly greater than either agent alone, but no significant difference was noted among the other parameters of toxicity studied.

Gastrointestinal pneumocystosis in HIV-infected patients on aerosolized pentamidine: report of five cases and literature review.

Extrapulmonary infection with Pneumocystis carinii in AIDS patients on aerosolized pentamidine is occurring more frequently. We report five patients diagnosed with gastrointestinal pneumocystosis while on aerosolized pentamidine prophylaxis and have identified infections involving the peritoneum, liver, and transverse colon, as well as stomach and duodenum. Physicians should have a high index of suspicion for extrapulmonary pneumocystosis, especially involving the gastrointestinal system, in HIV-infected patients, and early diagnosis must be pursued aggressively. The use of aerosolized pentamidine as prophylaxis for P. carinii pneumonia is not protective against gastrointestinal pneumocystosis because of inadequate systemic distribution of the drug. To our knowledge, this is the first report in a clinical journal documenting and photographing P. carinii organisms in ascitic fluid.

Severe hemorrhage caused by gastrointestinal Kaposi's syndrome in patients with the acquired immunodeficiency syndrome: treatment with endoscopic injection sclerotherapy.

Kaposi's sarcoma (KS) is the most common tumor among HIV-infected individuals, but its involvement in the gastrointestinal tract was reported long before the AIDS epidemic. Although most cases of gastrointestinal KS are asymptomatic, advanced lesions may occasionally result in a severe and life-threatening hemorrhage that requires immediate treatment. At the NYU Medical Center, we have seen three AIDS patients present with severe upper tract bleeding (> 8 U/48 h) from KS lesions of the antrum, fundus, and duodenum. The last patient was also bleeding from an ulcerated rectal KS lesion. Because all three patients had a coexisting thrombocytopenia (platelets < 50,000/mm3) and were poor operative risks, injection sclerotherapy was performed. All four KS lesions stopped bleeding, and three out of the four lesions decreased in size. To our knowledge, this is the first report of successfully using sclerotherapy to treat severe hemorrhage due to gastrointestinal KS.

Mortality at ages 75 and older in the Cancer Prevention Study (CPS I).

In the fall of 1959 the American Cancer Society began a comprehensive epidemiologic investigation of more than one million men and women drawn mainly from the middle-class population. The study reported here presents a portion of the investigation relating to the mortality among 49,469 subjects who attained age 75 years and older during the course of the study. Both men and women who at entry into this study (1960) were judged to be in good health registered distinctly lower mortality than those judged to be in poor health. Men and women with some college education had significantly lower death rates than those with lesser schooling. Men and women who reported a good family history of longevity showed consistently lower death rates in each five-year age group than those with average or poor family history of longevity. Persons with an average family history of longevity generally had lower death rates than those with a poor family history of longevity. Analysis of mortality by cause indicated that at ages 75 and older nearly half the deaths were attributed to all forms of heart disease. Coronary heart disease accounted for about 35 percent of all deaths, with the proportion decreasing with age. Deaths from stroke rose from 15 to about 20 percent with increase in age. Deaths from all sites of cancer declined with advancing age in both sexes, from about 16 percent of all deaths at ages 75 to 79 to about six percent at ages 90 to 99. Among men, cancer of the prostate accounted for 3.5 percent of deaths at ages 75 to 84, decreasing to about one half this proportion in the early-90s age group. Colorectal cancer decreased from about three percent of total deaths at ages 75 to 84 to about 1.5 percent in the early 90s. Lung cancer and stomach cancer remained at the same level at these ages.

Mortality and weight: insured lives and the American Cancer Society studies.

Recent investigations of the relation of mortality to weight have involved more than 4 million insured persons in a study by insurance companies and over 1 million men and women in a study by the American Cancer Society. These studies present a large volume of information on the effects of underweight and overweight on death rates of healthy middle-class Americans, free of the confounding effects of low socioeconomic status and associated health impairments. However, only the American Cancer Society's study separates findings by smoking status. These investigations indicate that the lowest mortality occurs among persons somewhat underweight and that mortality rises steadily as weight increases. The study of insured persons shows that among underweight persons mortality is relatively high initially but declines with time, whereas among overweight persons mortality is low initially but increases to distinctly higher levels after about 15 years.

Actuarial contributions to life table analysis.

The correct principles for the construction of life tables and more particularly select life tables were developed by actuaries in England in the first half of the 19th century. Actuaries explored the phenomenon of selection not only between the insured and annuitants but also in the general population, distinguishing among initial temporary selection, antiselection, and class selection. The conclusion was reached early that no such thing as an unselected population exists. Group life insurance experience among the actively employed has been shown to provide a more appropriate standard of expected mortality than general population death rates in studies of medical impairments and occupational hazards at ages under 65 years. Mortality rates derived from the Cancer Prevention Study can serve as a useful standard of expected mortality when the objective is determination of excess mortality compared with ostensibly healthy persons at ages 65 years and older.