***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: A concomitant dosage regimen of a histamine 2 receptor antagonist with a proton pump inhibitor ( PPI ) effectively decreases the incidence of nocturnal acid breakthrough , which is one of the problems encountered when acid‐related diseases are treated with a PPI alone . We compared the effectiveness of an increased dosage regimen of rabeprazole with that of a concomitant dosage regimen of rabeprazole with famotidine , relative to cytochrome P450 ( CYP ) 2C19 genotype status , on nocturnal acid inhibition Background : Pantoprazole is a new substituted benzimidazole that blocks the H+/K+‐ATPase in the gastric mucosa and thus inhibits acid secretion : We have previously shown that 70 % of patients experience nocturnal gastric acid breakthrough ( defined as pH < 4 for more than 60 min between 22.00 and 06.00 hours ) on twice a day ( b.d . ) proton pump inhibitor . Adding 150 or 300 mg of ranitidine at bedtime is more effective than additional omeprazole at bedtime in control of night‐time acid breakthrough BACKGROUND & AIMS Adding histamine 2 receptor antagonists ( H2RAs ) to proton pump inhibitor ( PPI ) therapy is a common practice to block nocturnal acid breakthrough ( NAB ) . Controversy exists over its efficacy because of H2RA intolerance . No prospect i ve study has addressed this issue . METHODS Twenty-three healthy volunteers and 20 gastroesophageal reflux disease ( GERD ) patients were studied .  Ambulatory pH monitoring was performed with one electrode in the gastric fundus and the other 5 cm above the lower esophageal sphincter . Baseline pH testing  was performed and repeated after 2 weeks on PPI twice daily before meals ( omeprazole 20 mg ) . All subjects then received 28 days of PPI plus H2RA Qhs ( ranitidine 300 mg ) with repeat pH testing on days 1 , 7 , and 28 . RESULTS Eighteen controls and 16 GERD patients completed all 5 studies . Compared with baseline , all 4 medication regimens decreased supine % time pH < 4 ( P = 0.001 ) . The administration of PPI + 1 day of H2RA was the only therapy that significantly decreased % time gastric pH < 4 for the supine period compared with PPI twice daily alone ( P < 0.001 ) . There was no difference in % time supine gastric pH < 4 between 2 weeks of PPI twice daily alone and either 1 week or 1 month of PPI + bedtime H2RA . CONCLUSIONS The combination of H2RA and PPI therapy reduced NAB only with the introduction of therapy . Because of H2RA tolerance , there is no difference in acid suppression between PPI twice daily and PPI twice daily + H2RA after 1 week of combination therapy BACKGROUND Barrett ’s oesophagus , columnar metaplasia of the epithelium , is a premalignant condition with a 50–100-fold increased risk of cancer . The condition is caused by chronic gastro-oesophageal reflux . Regression of metaplasia may decrease the cancer risk . AIMS To determine whether elimination of acid gastro-oesophageal reflux induces a regression of metaplastic epithelium . METHODS Sixty eight patients with acid reflux and proven Barrett ’s oesophagus were included in a prospect i ve , r and omised , double blind study with parallel groups , and were treated with profound acid secretion suppression with omeprazole 40 mg twice daily , or with mild acid secretion suppression with ranitidine 150 mg twice daily , for 24 months . Endoscopy was performed at 0 , 3 , 9 , 15 , and 24 months with measurement of length and surface area of Barrett ’s oesophagus ; pH-metry was performed at 0 and 3 months . Per protocol analysis was performed on 26 patients treated with omeprazole , and 27 patients treated with ranitidine . RESULTS Omeprazole  reduced reflux to 0.1 % , ranitidine to 9.4 % per 24 hours . Symptoms were ameliorated in both groups . There was a small , but statistically significant regression of Barrett ’s oesophagus in the omeprazole group , both in length and in area . No change was observed in the ranitidine group . The difference between the regression in the omeprazole and ranitidine group was statistically significant for the area of Barrett ’s oesophagus ( p=0.02 ) , and showed a trend in the same direction for the length of Barrett ’s oesophagus ( p=0.06 ) . CONCLUSIONS Profound suppression of acid secretion , leading to elimination of acid reflux , induces partial regression of Barrett ’s oesophagus Symptomatic patients with endoscopically verified reflux oesophagitis were r and omised to a double blind trial in which they received either omeprazole ( 20 mg once daily ) or cimetidine ( 400 mg four times daily ) for four , and if necessary , eight weeks . In an ' intention to treat ' analysis , oesophagitis was found to have healed after four weeks in 77 of 137 ( 56 % ) in the omeprazole group and in 34 of 133 ( 26 % ) in the cimetidine group ( p less than 0.001 ) . By eight weeks these values were 71 % and 35 % respectively ; p less than 0.001 . Histological assessment s were available for 73 % of the patients . At entry , 63 % ( 66 of 104 ) in the omeprazole group and 60 % ( 56 of 94 ) in the cimetidine group ( ns ) had abnormal histology . After the study , the proportions of patients who initially had had abnormal histology but who then progressed to normal were 67 % ( 44 of 66 : omeprazole ) and 48 % ( 27 of 56 : cimetidine ) respectively ( p less than 0.001 ) . All patients had reflux symptoms at entry . After four weeks , 46 % in the omeprazole group and 22 % ( p less than 0.001 ) in the cimetidine group were asymptomatic . Diary cards completed for the first two weeks showed that patients treated with omeprazole experienced fewer reflux symptoms by day and night and used fewer antacids .  Omeprazole , 20 mg once a day for four to eight weeks , healed a greater proportion of patients with reflux oesophagitis than cimetidine , 1.6 g per day , assessed endoscopically and histologically , and relieved more patients ' symptoms BACKGROUND & AIMS Proton pump inhibitors administered twice daily do not provide complete nocturnal acid suppression .  Acid breakthrough , or decrease in intragastric pH to < 4 for an hour or longer , occurs in three quarters of normal subjects and patients at night . We compared the effect of a third dose of omeprazole at bedtime with that of a dose of ranitidine at bedtime on residual nocturnal acid secretion in patients receiving omeprazole twice daily . METHODS Twelve volunteers underwent overnight intragastric pH monitoring after 7 days of treatment with omeprazole  , 20 mg twice daily , followed by different treatment supplements at bedtime : placebo ; additional omeprazole , 20 mg ; ranitidine , 150 mg ; and ranitidine , 300 mg . RESULTS Additional omeprazole at bedtime reduced the percentage of time with intragastric pH of < 4 from 48 % to 31 % ( P < 0.005 ) compared with omeprazole twice daily with placebo at bedtime . Ranitidine at bedtime reduced this parameter more , 5 % with 150 mg and 6 % with 300 mg ( P < 0.01 vs. omeprazole twice daily plus bedtime ) . Results for percentage of time with intragastric pH <3 were similar . Eleven subjects had acid breakthrough with placebo at bedtime ; 7 with omeprazole at bedtime ( P = NS ) ; 4 with ranitidine , 150 mg at bedtime ; and 3 with ranitidine , 300 mg at bedtime ( P < 0 . 05 , ranitidine vs. placebo ) . CONCLUSIONS Bedtime ranitidine is more effective than bedtime omeprazole on residual nocturnal acid secretion in patients receiving omeprazole twice daily . This finding suggests that fasting breakthrough nocturnal acid secretion in patients receiving omeprazole twice daily is most likely histamine related In some patients , proton pump inhibitors do not abolish nocturnal gastric acidity and additional evening antisecretory medication may be required . In 16 subjects with chronic heartburn , 24-hr gastric and esophageal pH were measured at baseline and again after six days of 20 mg omeprazole alone at 08:00 hr followed by placebo , 75 mg ranitidine , or 20 mg omeprazole at 22:00 hr . Integrated acidity was calculated from the cumulative , time-weighted mean acid concentrations ( derived from pH values for each second ) . Baseline integrated gastric acidity increased progressively over 24 hr , whereas integrated esophageal acidity increased only until 22:00 hr . Morning omeprazole nearly abolished 24-hr esophageal acidity and significantly decreased overall gastric acidity but did not abolish nocturnal gastric acidity . Adding evening ranitidine or omeprazole nearly eliminated the nocturnal increase in gastric acidity . Integrated acidity was more sensitive than time pH < 4 in assessing gastric and esophageal acidity as well as their inhibition by omeprazole and ranitidine . In conclusion , integrated acidity provides novel information regarding the synergy of omeprazole plus ranitidine . Adding low-dose ranitidine helps control nocturnal gastric acidity that can occur with conventional omeprazole administration . Although the heartburn patients in the present study had nocturnal gastric acidity without accompanying nocturnal esophageal acid reflux , other patients who do have nocturnal esophageal reflux might profit from addition of bedtime ranitidine or another gastric antisecretory agent Objectives : We aim ed to determine if nocturnal acid breakthrough occurs in children receiving proton pump inhibitors for reflux esophagitis , and to compare the healing of esophagitis in children with nocturnal acid breakthrough receiving  proton pump inhibitors ± ranitidine . Methods : This is a prospect i ve , double-blind study . Endoscopic and histologic esophagitis were scored 0 - 4 and 0 - 3 , respectively . Patients were treated with a proton pump inhibitor twice daily and esophagogastric pH monitoring was performed at week 3 . Patients with nocturnal acid breakthrough were r and omized . One group received ranitidine and the other received placebo at bedtime in addition to proton pump inhibitor therapy . Endoscopy was performed on all patients ( with pH monitoring on patients with nocturnal acid breakthrough ) during the 17th week of therapy . Results : We enrolled 18 patients , ages 1 to 13 years ( mean = 10.3 years ) . Mean baseline endoscopic and histologic scores were 3.1 + /− 1.4 and 1.8 + /− 0.7 , respectively . Mean dose of proton pump inhibitor was 1.3 mg/kg + /− 0.6 . Nocturnal acid breakthrough was documented in 16/18 ( 89 % ) patients . Seven patients received ranitidine and 9 received  placebo . The reflux index improved : mean of 14.3 at baseline , 2.0 at week 3 ( P = 0.0001 ) , and 5.1 at week 17 ( P = 0.09 ) . Nocturnal acid breakthrough persisted in 9/12 ( 75 % ) patients , 3 of whom received ranitidine at bedtime . Esophagitis improved in all patients following therapy : mean endoscopy and histology scores were 1.6 + /− 1.8 ( P = 0.0020 ) and 0.8 + /− 0.9 ( P = 0.0013 ) , respectively . Symptoms significantly improved from a mean score of 2.0 at baseline to 0.4 at week 17 ( P = 0.0001 ) . Conclusions : Nocturnal acid breakthrough is common in pediatric patients treated with proton pump inhibitors .  Reflux index remains normal in spite of nocturnal acid breakthrough . Symptoms and esophagitis continued to improve during therapy in spite of nocturnal acid breakthrough . There appears to be no additional benefit to supplementation with ranitidine at bedtime Proton pump inhibitors taken twice daily before meals ( proton pump inhibitor b.d . AC ) effectively controls daytime gastric pH ; however , nocturnal gastric acid breakthrough ( NAB ) occurs in more than 75 % of patients . Adding an H2‐blocker at bedtime decreases NAB in normal subjects . The efficacy of this regimen has not been evaluated in GERD patients . The aim of this study was to assess 
    Output:
    
The results show that additional bedtime H2RAs can decrease the prevalence rate of nocturnal gastric acid breakthrough .