CLINICAL
PHARMACOLOGY OF
GASTROINTESTINAL
AGENTS
Treatment of peptic ulcer
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Antimicrobial agents (tetracycline, bismuth subsalicylate, and
metronidazole) to eradicate H. pylori infection
Misoprostol (a prostaglandin analog) to inhibit gastric acid secretion and
increase carbonate and mucus production, to protect the stomach lining
Antacids to neutralize acid gastric contents by elevating the gastric pH, thus
protecting the mucosa and relieving pain
Avoidance of caffeine and alcohol to avoid stimulation of gastric acid
secretion
Anticholinergic drugs to inhibit the effect of the vagal nerve on acidsecreting cells
H2 blockers to reduce acid secretion
Sucralfate, mucosal protectant to form an acid-impermeable membrane that
adheres to the mucous membrane and also accelerates mucus production
Dietary therapy with small infrequent meals and avoidance of eating before
bedtime to neutralize gastric contents
Insertion of a nasogastric tube (in instances of gastrointestinal bleeding) for
gastric decompression and rest, and also to permit iced saline lavage that
may also contain norepinephrine
Gastroscopy to allow visualization of the bleeding site and coagulation by
laser or cautery to control bleeding
Surgery to repair perforation or treat unresponsiveness to conservative
treatment, and suspected malignancy.
Ranitidine (Ranitidin)
Forms of production: 0,15 g and 0,3 g tablets and ampoules with 2 ml of
2,5 % solution.
RECOMMENDATIONS OF
HELICOBACTER PYLORI ERADICATION
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omeprazole 20mg
amoxicillin 1000mg
clarithromycin 500mg, all twice daily for 7 days.
An alternative regimen with a similar eradication
rate of around 90% is:
• omeprazole 20mg
• clarithromycin 250mg
• metronidazole 400mg, again all twice daily for 7
days.
A typical quadruple therapy
a PPI twice a day
 bismuth 120 mg four times a day
 metronidazole 400 mg three times a day
 oxytetracycline 500 mg four times a day,
all for 7 days.
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Ulcers associated with NSAIDs
 omeprazole 20mg daily is preferable to ranitidine
150mg twice daily as the respective rates of healing
are 80% and 63%.
 H2RAs are slow to heal the ulcers if the offending drug
is not stopped and so, under these conditions, a PPI is
preferred.
 H pylori eradication is no more effective than
omeprazole alone to heal ulcers, but if the infection is
present, then eradication will reduce the rate of
relapse.
 H pylori is not associated with an increased risk of
ulcer with NSAIDs in the elderly but there is an
increased risk of bleeding.
Motilium
Form of production: 0,01 g tablets
LAXATIVES AND CATHARTICS
Indications for Use
• 1. To relieve constipation in pregnant women, elderly clients whose
abdominal and perineal muscles have become weak and atrophied,
children with megacolon, and clients receiving drugs that decrease
intestinal motility (eg, opioid analgesics, drugs with anticholinergic
effects)
• 2. To prevent straining at stool in clients with coronary artery disease
(eg, postmyocardial infarction), hypertension, cerebrovascular
disease, and hemorrhoids and other rectal conditions
• 3. To empty the bowel in preparation for bowel surgery or diagnostic
procedures (eg, colonoscopy, barium enema)
• 4. To accelerate elimination of potentially toxic substances from the
GI tract (eg, orally ingested drugs or toxic compounds)
• 5. To prevent absorption of intestinal ammonia in clients with hepatic
encephalopathy
• 6. To obtain a stool specimen for parasitologic examination
• 7. To accelerate excretion of parasites after anthelmintic drugs have
been administered
• 8. To reduce serum cholesterol levels (psyllium products)
Contraindications to Use
Laxatives and cathartics should not be
used in the presence of undiagnosed
abdominal pain. The danger is that the drugs
may cause an inflamed organ (eg, the
appendix) to rupture and spill GI contents
into the abdominal cavity with subsequent
peritonitis, a life-threatening condition. Oral
drugs also are contraindicated with intestinal
obstruction and fecal impaction.
Antidiarrheals
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Antidiarrheal drugs are indicated in the following
circumstances:
1. Severe or prolonged diarrhea (>2 to 3 days), to prevent severe
fluid and electrolyte loss
2. Relatively severe diarrhea in young children and older adults.
These groups are less able to adapt to fluid and electrolyte losses.
3. In chronic inflammatory diseases of the bowel (ulcerative colitis
and Crohn’s disease), to allow a more nearly normal lifestyle
4. In ileostomies or surgical excision of portions of the ileum, to
decrease fluidity and volume of stool
5. HIV/AIDS-associated diarrhea
6. When specific causes of diarrhea have been determined
Contraindications to Use
Contraindications to the use of antidiarrheal drugs
include diarrhea caused by toxic materials,
microorganisms that penetrate intestinal mucosa (eg,
pathogenic E. coli, Salmonella, Shigella), or antibioticassociated colitis. In these circumstances, antidiarrheal
agents that slow peristalsis may aggravate and prolong
diarrhea. Opiates (morphine, codeine) usually are
contraindicated in chronic diarrhea because of possible
opiate dependence. Difenoxin, diphenoxylate, and
loperamide are contraindicated in children younger than
2 years of age.
Chronic pancreatitis
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There is no cure for chronic pancreatitis. Once the pancreas is
damaged, then it is not able to return to normal function and there
is always the potential for further attacks. Treatment is, therefore,
directed towards preventing attacks, controlling the pain and
treating the complications.
Preventing symptoms worsening
Patients with chronic pancreatitis should avoid alcohol altogether. If
the pancreatitis is due to excess alcohol consumption, then this is
essential. If it is due to other causes, then it seems sensible to avoid
a substance which is capable of damaging the pancreas.
If an underlying cause has been identified then this should be
treated. Disorders of calcium metabolism and of fat metabolism will
be treated appropriately. Your doctor may recommend removal of
the gall bladder if pancreatitis is thought to be caused by gall
stones.
Chronic pancreatitis
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Preventing attacks
The long-standing principle has been to try and rest the pancreas.
This involves giving pancreatic supplements such as Creon (which
contain pancreatic enzymes in high concentration) together with
drugs which reduce acid secretion by the stomach. Patients should
also follow a low-fat diet.
These measures reduce the presence of fat in the duodenum,
reduce acid in the duodenum and reduce the need for pancreatic
enzyme secretion. These measures are very successful in about a
third of patients, moderately successful in a third and unhelpful in a
third.
Some eminent specialists have supported the use of antioxidants in
the treatment of chronic pancreatitis. These antioxidants include
selenium and vitamin C.
Chronic pancreatitis
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Control of pain
This is a very important aspect of the treatment of chronic
pancreatitis. Pancreatic pain varies in severity from mild
(controllable with simple analgesics such as paracetamol (eg
Panadol)) to severe (requiring morphine-like drugs for control).
In addition to the preventive measures listed above, the basic
principle is to use the drug lowest down the analgesic ladder which
controls the pain. Since the pain is often worse at night and since
both body and mind are at their lowest ebb in the early hours of the
morning, the lowest rung of the analgesic ladder may be pethidine
or morphine (eg MST continus tablets). Since the pain is chronic and
severe, there is a fine line between adequate analgesia and
addiction.