514
`
`Gut, 1990,31,514-517
`
`Abolition by omeprazole of aspirin induced gastric
`mucosal injury in man
`
`T K Daneshmend, A G Stein, N K Bhaskar, C JHawkey
`
`Abstract
`This study investigates whether aspirin injury
`to the human gastric mucosa can be prevented
`by profound acid suppression with omepra(cid:173)
`zole, in a randomised, double blind, crossover
`design according to latin square. It was con(cid:173)
`cluded that profound acid suppression can
`prevent aspirin induced gastric mucosal injury
`in normal subjects. This approach may pre(cid:173)
`vent the development of peptic ulcers and their
`complications in patients taking aspirin and
`other non-steroidal anti-inflammatory drugs.
`
`bd for the last 48h; (c) omeprazole 20 mg each
`morning for seven days plus aspirin 900 mg bd
`for the last 48 h; and (d) omeprazole 40 mg bd for
`seven days plus aspirin 900 mg bd for the last
`48 h. The last doses of omeprazole and aspirin
`(or the corresponding placebo) were taken at
`0700 hand 07 30 h - that is, 120 and 90 minutes,
`respectively, before' measurement of gastric
`blood loss. Each of the above regimens was
`separated by a seven day washout period. The
`order of treatments was randomised according to
`a latin square design and the study conducted in
`double blind manner.
`
`Aspirin and non-steroidal anti-inflammatory
`drugs are strongly associated with peptic ulcer
`complications in the elderly in Britain. 1-5 Assum(cid:173)
`ing that
`the association may be causative, a
`number of approaches have tried to reduce the
`extent of damage caused by these agents. 6
`Although old people appear to be at greatest risk,
`it is difficult to evaluate possible therapeutic
`manoeuvres in this population. We have there(cid:173)
`fore investigated healthy adult volunteers whose
`acute responses appear to reflect those of older
`patients. 7 Our previous studies show that acid
`inhibition by ranitidine8 and famotidine9 results
`in a reduction in gastric mucosal damage, as
`quantified by the rate ofgastric mucosal bleeding
`and endoscopic appearance, but aspirin induced
`damage was not totally abolished.
`In the present study we have examined the
`hypothesis that gastric acid is necessary for the
`occurrence of aspirin induced gastric damage.
`To achieve virtual gastric anacidity we used
`omeprazole, an irreversible inhibitor of the
`proton pump in gastric parietal cells. 10
`
`Methods
`
`SUBJECTS
`(eight
`Sixteen healthy non-smoking adults
`men; age range 19-25 years) were studied. They
`took no regular medication, except the contra(cid:173)
`ceptive pill. All had normal biochemical and
`haematological
`values,
`including
`platelet
`count, prothrombin time and activated partial
`thromboplastin time. The study was approved
`by the Nottingham Medical School Ethical
`Committee and subjects gave written informed
`consent.
`
`STUDY DESIGN
`Gastric blood loss was measured in each subject
`on four occasions, at the end of each of the
`following regimens: (a) placebo omeprazole plus
`placebo aspirin, both for seven days; (b) placebo
`omeprazole for seven days plus aspirin 900 mg
`
`SAMPLE COLLECTION
`Gastric blood loss was determined after an
`overnight fast,
`the final doses being taken at
`0700 hand 07 30 h on the study day. At 0900 h
`each subject swallowed a 16 French gauge Salem
`sump orogastric tube. After aspiration of resting
`gastric juice, the stomach was rinsed three times
`with distilled water (not a glucose solution) as
`originally described by HunL 11 The first of three
`10 minute study periods then commenced. Half
`way during each period phenol red (2 mg in 15 ml
`water) was introduced through the orogastric
`tube and dispersed around the stomach. After
`nine minutes, distilled water 100 ml was intro(cid:173)
`duced, dispersed and then aspirated by 10
`minutes. After two more rinses a second 10
`minute study period started, and after
`two
`further rinses there was a third 10 minute study
`period. The subjects were recumbent on their
`left side to reduce pyloric loss of gastric contents,
`except when liquids were introduced into the
`stomach when a standard series of manoeuvres
`was performed in order
`to ensure maximal
`contact with the gastric mucosa.
`
`ASSA YS
`The pH of resting gastric JUIce and gastric
`washings was measured immediately after collec(cid:173)
`tion using a glass electrode (Corning). The
`volume of blood in gastric aspirates was quanti(cid:173)
`fied by the peroxidase activity of haemoglobin,
`using the orthotolidine reaction. II 12 Briefly,
`samples in citrate buffer were mixed with
`orthotolidine. The rate of development of a blue
`colour was determined on a spectrophotometer
`at 640 nmol between 30 and 60 sec after addition
`of hydrogen peroxide. This was compared with
`values from a standard curve constructed using
`the subjects own blood. Gastric blood loss was
`expressed as !J,l of blood/10 min period after
`correction for phenol red recovery. The median
`value from the three 10 minute periods was used
`for analysis. Phenol red concentration in gastric
`aspirates obtained during the study periods was
`
`University Department t::
`Therapeutics, University
`Hospital, Nottingham
`T K Daneshmend
`A G Stein
`N KBhaskar
`CJ Hawkey
`Correspondence to:
`Dr T K Daneshmend, Dept of
`Medicine, Royal Devon and
`Exeter Hospital, Wonford
`Barrack Road, Exeter
`EX25DW.
`Accepted for publication
`10 August 1989
`
`Page 1 Dr. Reddy's Exh. 1046
`
`

`

`Abolition by omeprazole ofaspirin induad gastric mucosal injury in man
`
`515
`
`TABLE Gastric mucosal blood loss, pH ofresting juice, pH ofgastric washings and phenol red recovery in 16 subjects after
`(a) placebo only, (b) aspirin 900 mg bd only, (c) aspirin 900 mg bd plus omi!prazole 20 mg mane, and (d) aspirin 900 mg bd plus
`Omi!prazole 40 mg bd
`
`Placebo
`
`Aspirin
`
`Aspirin plus
`Aspirin plus
`Omeprazole ZO mg mane Omeprazole 40 mg bd
`
`Gastric musocal blood loss 1'1/10 min
`geometric mean (95% CI)
`Initial pH median (lower-upper quartiles)
`Gastric aspirate pH median (lower-upper
`quartiles)
`Phenol red recovery (%) mean (SD)
`
`1-4 (0-8-2-4)
`3-IZ (Z-07-Z-93)
`
`16-1 (9-5-27-5)'
`3'IZ(Z'31-S'19)
`
`304 (1-4--S-Z)t
`6-01 (4-ZS-7-3Z)§
`
`2-43 (I-94--Z-S3)
`54·6 (I I -5)
`
`Z-Z6 (Z-II-Z'S8)
`57'6(9'7)
`
`3·07 (2-66--{,'SZ)
`6304 (13'1)
`
`2-4 (I- 3-4-4):j:
`6-60 (4'91-7-16)§
`
`6-65 (S'S9-6'88)§
`61·1 (11'0)
`
`'p<O'OI compared with placebo; tp<O'OI compared with aspirin alone; :j:p<O'OOI compared with aspirin plus omeprazole ZO mg/day,
`and NS compared with placebo; §p<O-OI compared with placebo.
`
`measured spectrophotometrically at 560 nmol,
`after adjustment of pH to 10·5 with sodium
`hydroxide.
`
`STATISTICAL METHODS
`Analysis of variance was used to assess the
`influence of aspirin and of omeprazole on gastric
`mucosal bleeding. To approximate to a normal
`distribution,
`these data were logarithmically
`transformed before computation and results
`given as geometric mean with 95% confidence
`limits. Phenol red recovery data were analysed in
`similar manner, but without logarithmic trans(cid:173)
`formation. Results are expressed as mean and
`standard deviation (SD). Friedman two way
`analysis of variance by ranks was used to assess
`the significance of changes in pH values and
`results expressed as medians and interquartile
`ranges.
`
`was slightly higher than placebo, this difference
`was not significant (p=0·07).
`The effects ofomeprazole on the pH of resting
`juice or of gastric washings are shown in the
`Table. The median initial pH was unaffected by
`aspirin (p=0'79), but
`increased significantly
`with omeprazole 20 mg/day and 40 mg bd
`(p=0'035 and p<O'OOl, respectively compared
`with placebo). The median initial pH was not
`significantly different between the two omepra(cid:173)
`zole dose regimens (p=0·4). The median pH of
`gastric washings is also given in the Table. The
`only notable difference was a lower pH with the
`lower omeprazole dose, while pH of washings
`remained at
`the initial value on the higher
`omeprazole dose, a difference which was signifi(cid:173)
`cant (p<O·Ol). Overall, the reduction in gastric
`mucosal bleeding rate was significantly corre(cid:173)
`lated with the pH of initial gastric aspirates
`(r=0'423, p<0·02).
`
`Results
`The rate of gastric mucosal bleeding after aspirin
`was over lO-fold greater than that after placebo
`(p<O'OOl) (Table and Figure). The value after
`aspirin plus omeprazole 20 mg/day was reduced
`significantly by 79% when compared with that
`after aspirin alone (p<O·Ol). Omeprazole 40 mg
`bd plus aspirin resulted in a gastric mucosal
`bleeding rate that was 85% less than after aspirin
`alone (p=O'OOl), and although the mean value
`
`Discussion
`Endoscopic observations implicating aspirin in
`the pathogenesis of iatrogenic gastric damage
`were made by Douthwaite ~nd Linton half a
`century ago. 13 The subsequent widespread use
`of
`aspirin
`and
`other
`non-steroidal
`anti(cid:173)
`inflammatory drugs has been implicated in
`peptic ulcer perforation rates
`in Britain.'
`Emergency admission because of bleeding from
`gastric and duodenal ulcers in the elderly is
`
`100
`
`90
`
`80
`
`70
`"E 60
`:i 50
`
`c::>
`
`_<:::
`
`40
`
`30
`
`20
`
`10
`
`0
`-c
`
`02
`
`co
`
`Placebo
`
`Aspirin
`
`Aspirin Ome 20 mg
`om
`Figure: Individual rates ofgastric mucosal blood loss (111110 min) in 16 normal adults on placebo, aspirin 900 mg bd only,
`aspirin 900 mg bd plus omi!prazole 20 mg each morning, and aspirin 900 mg bd plus Omi!prazole 40 mg bd.
`
`Aspiri~~me 40 mg
`
`Page 2 Dr. Reddy's Exh. 1046
`
`

`

`516
`
`Daneshmend, Stein, Bhaskar, Hawkey
`
`associated with aspirin and other non-steroidal
`anti-inflammatory drug use in our hospital popu(cid:173)
`lation. I .{ 14 Aspirin ingestion is associated with a
`relative risk of three, even for short periods of
`exposure. I 14 Moreover, aspirin can provoke
`gastric mucosal bleeding at doses of up to 75 mg
`taken daily for five days or less. IS It is evident that
`aspirin is probably responsible for a spectrum of
`damage, ranging from acute gastric erosions to
`peptic ulcer complications.
`In our present study aspirin induced gastric
`mucosal damage (as quantified by gastric mucosal
`blood loss) was abolished by omeprazole 40 mg
`bd, a dose that produces virtual anacidity. 16
`Quantification of gastric mucosal
`injury by
`measurement of gastric mucosal blood loss
`closely reflects direct endoscopic evidence of
`mucosal damage: we have previously shown
`gastric mucosal blood loss to correlate with the
`extent of petechial haemorrhage seen endo(cid:173)
`scopically.9 Our findings accord with a small
`endoscopic study recently reported in abstract
`form which showed prevention by omeprazole of
`gastric injury after a single aspirin dose. 17
`The dissociation constant (pKa) of aspirin
`is 3·5. Thus at the levels of intragastric pH
`achieved with omeprazole in our study, aspirin
`ionisation is virtually complete. In this form
`passive absorption of aspirin into the gastric
`mucosa does not occur. 18 In contrast, at normal
`almost
`entirely
`intragastric pH aspirin is
`unionised an4 able to diffuse passively into cells
`of the gastric epithelium where a neutral pH
`results in reionisation and intracellular trapping
`of salicylate in high concentrations. The conse(cid:173)
`quent topical toxicity of salicylates is well recog(cid:173)
`nised and results in impaired barrier function,
`reduced mucus and bicarbonate secretion, and
`capillary injury. 1920 The underlying metabolic
`changes are not firmly established, but in the
`presence ofacid aspirin may achieve intracellular
`levels sufficient
`to uncouple oxidative phos(cid:173)
`phorylation or
`interfere with carbohydrate
`metabolism.21 As most other non-steroidal anti(cid:173)
`inflammatory drugs are weak acids, similar con(cid:173)
`siderations are likely to apply although direct
`evidence is lacking.
`Apart from these specific benefits, acid inhibi(cid:173)
`tion may result in other non-specific advantages.
`Gastric acid enhances mucosal injury caused by a
`variety of stimuliII and damages the basal lamina
`resulting in impaired epithelial restitution. 23 In
`addition, the activity of pepsin is pH dependent
`and is inhibited at high pH. Whatever the
`mechanism,
`the observations presented here
`strongly support the hypothesis that gastric acid
`is crucial in the genesis of aspirin- (and possibly
`other non-steroidal anti-inflammatory drug-)
`related gastroduodenal injury. Our data show
`that the reduction in gastric mucosal bleeding
`rate bears a close relationship to the intragastric
`pH achieved with omeprazole. In this context, it
`is notable that patients with pernicious anaemia
`and resultant achlorhydria are resistant to aspirin
`injury compared with healthy controls. 24 Even
`with achlorhydria, however,
`there was slight
`injury, possibly because aspirin itself acted as a
`source of exogenous acid. 24
`It is possible, however, that oral omeprazole
`protects the gastric mucosa by additional acid
`
`independent mechanisms. In animals, omepra(cid:173)
`zole given by the oral route is much more
`effective than when given parenterally in pre(cid:173)
`venting aspirin induced gastric damage despite
`complete inhibition of gastric acid. 25 26 In addi(cid:173)
`tion, oral omeprazole protects against ethanol
`induced gastric damage if given between IS to 60
`minutes before ethanol, there being no effect
`evident 3·5 h after the dose. This protective
`effect of omeprazole is not mediated through
`gastric mucosal prostaglandins,27 changes in
`gastric mucosal blood flow, 28 or alterations in
`gastric mucosal bicarbonate secretion.29 It may
`be the result of a direct effect of omeprazole on
`the vascular endothelium,3° as omeprazole also
`protects human gastric epithelial cells in vitro
`from indomethacin induced damage. 31
`From these and previous data it is clear that
`aspirin remains injurious to the human gastric
`mucosa until pH values approaching neutrality
`are reached. Greater suppression of acid may be
`needed to protect the gastroduodenal mucosa
`against aspirin and other non-steroidal anti(cid:173)
`inflammatory drugs than is adequate for ulcer
`healing. Profound suppression of acid, however,
`may not be without risk. An increased incidence
`of enteric infection is recognised but
`this is
`nonetheless relatively uncommon. At neutral pH
`(however achieved) serum gastrin concentra(cid:173)
`tions are raised.32 Whether there is a real risk of
`gastric carcinoid tumours in man given omepra(cid:173)
`zole is much less clear. There is no evidence in
`man that the small rises in plasma gastrin seen
`antisecretory drugs32 produce
`with gastric
`any sustained hyperplastic change in entero(cid:173)
`chromaffin like cells. 33 For the frail elderly
`patient at high risk of developing aspirin or other
`non-steroidal anti-inflammatory drug associated
`ulceration, bleeding, perforation or death the
`benefits of profound acid suppression with
`omeprazole are likely to outweigh the risks of
`enterochromaffin like cell carcinoid tumour
`development. Although our study showed a
`statistically significant advantage of omeprazole
`40 mg bd over omeprazole 20 mg each morning
`in reducing gastric mucosal bleeding, the higher
`dose may not necessarily confer a clinical advan(cid:173)
`trial of this approach, using
`tage. A clinical
`omeprazole 20 mg once per day, would therefore
`be justified in patients at risk of gastric damage
`from aspirin and non-steroidal anti-inlammatory
`drugs. Recent prospective studies in patients
`have shown that ranitidine34 and misoprostop5
`attenuate the damaging effects of non-steroidal
`anti-inflammatory drugs on the upper gastro(cid:173)
`intestinal tract. Ranitidine, however, has a pre(cid:173)
`ferential protective effect on the duodenum but
`did not protect against drug induced gastric
`ulceration,34 while the converse was true of
`misoprostol.35 In this context, it is possible that
`omeprazole may possess an advantage (as yet
`untested) because of its more potent acid inhibit(cid:173)
`ing action and be capable of attenuating non(cid:173)
`steroidal
`anti-inflammatory
`drug
`induced
`damage in both stomach and duodenum.
`
`These data were presented to the British Society of Gastro(cid:173)
`enterology Autumn Meeting: Sheffield September 14-16, 1988.
`We thank Dr Keith Gillon and Astra Clinical Research Unit,
`Edinburgh, for supply of study medication and financial support.
`
`Page 3 Dr. Reddy's Exh. 1046
`
`

`

`Abolition by omeprazole ofaspirin inducedgastric mucosal injury in man
`
`517
`
`1 Coggan D, Langman MjS, Spiegelhalter D. Aspirin, para(cid:173)
`cetamol and haematemesis and melaena. Gut 1982; 23:
`340-3.
`2 Collier DS, Pain jA. Non-steroidal antiinflammatory drugs
`and peptic ulcer perforation. Gut 1985; 26: 359-63.
`3 Somerville KW, Faulkner G, Langman MjS. Non-steroidal
`anti-inflammatory drugs and bleeding peptic ulcer. Lancet
`1986; i: 462-4.
`4 Walt RP, Katchinski B, Faulkner G, Logan RFA, Langman
`MjS. Non-steroidal anti-inflammatory drugs and bleeding
`peptic ulcer. Lancet 1986; i: 489-92.
`5 Armstrong CP, Blower AL. Peptic ulcer complications and
`non-steroidal antiinflammatory drugs [Abstract]. Gut 1986;
`27: A609.
`6 Hawkey Cj, Prichard Pj, Somerville KH. Strategies for
`preventing aspirin-induced gastric bleeding. Scand J
`Gastroenterol1986; 21 [suppI125]: 170-3.
`7 johnson PC. Gastrointestinal consequences of treatment
`with drugs in elderly patients. Am Geriatr Soc 1982; 30:
`S52-5-57.
`Kitchingman GK, Prichard Pj, Daneshmend TK, Walt RP,
`Hawkey Cj. Human gastric mucosal bleeding induced by
`aspirin 300 mg and its prevention by ranitidine [Abstract].
`Gut 1988; 29: A711.
`9 Daneshmend TK, Prichard Pj, Bhaskar NK, Millns Pj,
`Hawkey Cj. The use of microbleeding and an ultra-thin
`endoscope
`to assess gastric mucosal protection by
`famotidine. Gastroenterology. 1989; 97: 944-9.
`10 Clissold SP, Campoli-Richards DM. Omeprazole: a pre(cid:173)
`liminary review of its pharmacodynamic and pharmaco(cid:173)
`kinetic properties, and therapeutic potential in peptic ulcer
`disease and Zollinger-Ellison syndrome. Drugs 1986; 32:
`15-47.
`~
`II Hunt jN. A procedure for measuring gastric bleeding caused
`by drugs. Dig Dis Sci 1977; 24: 525-8.
`12 Hawkey Cj, Simpson G, Somerville KW. Reduction by
`enprostil of aspirin-induced blood loss from human gastric
`mucosa. AmJ Med 1986; 81 [suppI2A]: 50-3.
`13 Douthwaite AH, Lintott GAM. Gastroscopic observations of
`the effects of aspirin and certain other substances on the
`stomach. Lancet 1938; ii: 1222-5.
`14 Prichard Pj, Somerville KW, Faulkner G, Langman MjS
`[Abstract]. Gut 1987; 28: AI40l.
`15 Prichard PJ, Kitchingman GK, Hawkey CJ. Gastric mucosal
`bleeding: what dose of aspirin is safe? [Abstract]. Gut 1987;
`28: A1401.
`16 Hetzel DJ, Shearman DJC. Omeprazole inhibition ofnoctur(cid:173)
`nal gastric secretion in patients with duodenal ulcer. Br J
`Clin Pharmacol1984; 18: 587-90.
`17 Bigard M-A, Isal J-P. Complete prevention by omeprazole
`of aspirin-induced gastric lesions
`in healthy subjects
`[Abstract]. Gut 1988; 29: A712.
`18 Flower RJ, Moncada S, Vane JR. Analgesic-antipyretics and
`anti-inflammatory agents: drugs employed in the treatment
`of gout. In: Gilman AG, Goodman LS, Rall TW, Murad F,
`eds. The Pharmacological basis of therapeutics. 7th ed. New
`York: Macmillan, 1985: 674-715.
`
`19 Davenport HW. Gastric mucosal haemorrhage in dogs. Effects
`of acid aspirin and alcohol. Gastroenterology 1969; 56: 439(cid:173)
`49.
`20 Hawkey CJ, Rampton DS. Prostaglandins and the gastro(cid:173)
`intestinal mucosa: are they important in its function, disease
`or treatment? Gastroenterology 1985; 89: 1161-88.
`21 Spenney JG, Marshall G. Uptake and intracellular concentra(cid:173)
`tion of salicylate and p-hydroxybenzoate in in-vitro fundic
`gastric mucosa. Gastroenterology 1883; 84: 1318.
`22 Morris GP, Wallace jL. The roles of ethanol and of acid in the
`production ofgastric mucosal erosions in rats. Virchows Arch
`(Cell Pathol) 1981; 32: 23-8.
`23 Black BA, Morris GP, Wallace jL. Effects of acid on the basal
`lamina of the rat stomach and duodenum. Virchows Arch
`(Cell Pathol) 1985; 50: 109-18.
`24 St John DJB, McDermott FT. Influence of achlorhydria on
`aspirin-induced occult gastrointestinal bleed loss: studies in
`pernicious anaemia. Br MedJ 1970; 2: 450-2.
`25 Mattsson H, Andersson K, Larsson H. Omeprazole provides
`protection against experimentally induced gastric mucosal
`lesions. EurJ Pharmacol1983; 91: 111-4.
`Isenberg JI, Johansson C. Oral omeprazole
`26 Kollberg B,
`protects gastric mucosa against ethanol. Gastroenterology
`1983; 84: 1212.
`27 Konturek SJ, Brzozowski T, Radecki T. Protective action of
`omeprazole, a benzimidazole derivative, on gastric mucosal
`damage by aspirin and ethanol in rats. Digestion 1983; 27:
`159-64.
`28 Mattsson H, Larsson H. Effect of omeprazole on gastric
`mucosal blood flow in the rat. ScandJ Gastroenterol1986; 21
`[suppI118]: 72-4.
`29 Mattson H, Carlsson K, Carlsson E. Omeprazole is devoid of
`effect on alkaline secretion in isolated guinea pig antral
`mucosa. In: Allen, Flemstrom, Garner, Silen, Turnbrg, eds.
`Mechanisms of mucosal protection in the upper gastrointestinal
`tract. New York: Raven Press, 1984: 141-6.
`30 Mattsson H. Protective effects of omeprazole in gastric
`mucosa. ScandJ Gastroenterol1986; 21 [suppI118]: 86-8.
`31 Romano M, Razandi M, Ivey KJ. Cimetidine and omeprazole
`directly protect human gastric epithelial cells in vitro.
`Gastroenterology 1987; 92: 1599.
`32 Lanzon-Miller S, Pounder RE, Hamilton MR, et ai. Twenty(cid:173)
`four-hour intragastric acidity and plasma gastrin concentra(cid:173)
`tion in healthy subjects and patients with duodenal or gastric
`ulcer or pernicious anaemia. Aliment Pharmacol Ther 1987;
`1: 225-37.
`33 Lamberts R, Creutzfeldt W, Stockmann F, Jacubaschke U,
`Mass S, Brunner G. Long-term omeprazole treatment in
`man: effects on gastric endocrine cell populations. Digestion
`1988; 39: 126-35.
`34 EhsanullahRSB,PageMC, TildesleyG, Wood JR. Prevention
`of gastroduodenal damage induced by non-steroidal anti(cid:173)
`inflammatory drugs: controlled trial ofranitidine. Br MedJ
`1988; 297: 1017-21.
`35 Graham DY, Agrawal NM, Roth SH. Prevention of NSAID(cid:173)
`induced gastric ulcer with misoprostol: multicentre, double(cid:173)
`blind, placebo-controlled trial. Lancet 1988; ii: 1277-80.
`
`Page 4 Dr. Reddy's Exh. 1046
`
`