A Textbook of Clinical Pharmacology and Therapeutics

• With regard to drug therapy, several drugs (see below) are
  effective. Documented duodenal or gastric ulcerations
  should be treated with an H 2 -blocker or proton-pump
  inhibitor.


• Test for the presence of H. pyloriby using the urease CLO
  test or antral biopsy at endoscopy.


• All suspected gastric ulcers should be endoscoped and
  biopsied to exclude malignancy, with repeat endoscopy
  following treatment, to confirm healing and for repeat
  biopsy.


• The current recommendation in relation to H. pyloriis
  summarized above. DRUGS USED TO TREAT PEPTIC ULCERATION BY
  REDUCING ACIDITY

ANTACIDS

Use and adverse effects

Antacids have a number of actions which include neutralizing

gastric acid and thus relieving associated pain and nausea,

reducing delivery of acid into the duodenum following a

meal, and inactivation of the proteolytic enzyme pepsin by

raising the gastric pH above 4–5. In addition, it is thought that

antacid may increase lower oesophageal sphincter tone and

reduce oesophageal pressure.

A number of preparations are available and the choice will

depend on the patient’s preference, often determined by the

effect on bowel habit (see Table 34.2).

In general terms, antacids should be taken approximately

one hour before or after food, as this maximizes the contact

time with stomach acid and allows the antacid to coat the

stomach in the absence of food.

Drug interactions

Magnesium and aluminium salts can bind other drugs in the

stomach, reducing the rate and extent of absorption of anti-

bacterial agents such as erythromycin,ciprofloxacin,isoni-

azid,norfloxacin,ofloxacin,pivampicillin,rifampicinand

most tetracyclines, as well as other drugs such as phenytoin,

itraconazole, ketoconazole, chloroquine, hydroxychloro-

quine, phenothiazines, ironandpenicillamine. They increase

the excretion of aspirin(in alkaline urine).

H 2 -RECEPTOR ANTAGONISTS

H 2 -receptors stimulate gastric acid secretion and are also

present in human heart, blood vessels and uterus (and pro-

bably brain). There are a number of competitive H 2 -receptor

antagonists in clinical use, which include cimetidineand

ranitidine. The uses of these are similar and will be con-

sidered together in this section. Because each drug is so

widely prescribed, separate sections on their individual

adverse effects, pharmacokinetics and interactions are given

below, followed by a brief consideration of the choice

between them.

Use

1. H 2 -receptor angonists are effective in healing both gastric
   and duodenal ulcers. A four-week course is usually

PEPTICULCERATION 249

Key points

General management of peptic ulceration

• Stop smoking.


• Avoid ulcerogenic drugs (e.g. NSAIDs, alcohol,
  glucocorticosteroids).


• Reduce caffeine intake.


• Diet should be healthy (avoid obesity, and foods that
  give rise to symptoms).


• Test for the presence of H. pylori.

The choice of regimen used to eradicate H. pylori is
based on achieving a balance between efficacy, adverse effects,
compliance and cost. Most regimens include a combination
of acid suppression and effective doses of two antibiotics.
A typical regime for eradication of H. pyloriis shown in
Table 34.1.
Eradication should be confirmed, preferably by urea breath
test at a minimum of four weeks post-treatment.

Non-steroidal anti-inflammatory
drug-associated ulcer

NSAID-related ulcers will usually heal if the NSAID is with-
drawn and a proton-pump inhibitor is prescribed for four
weeks. If the NSAID has to be restarted (preferably after heal-
ing), H 2 -receptor antagonists or proton-pump inhibitors or
misoprostol(see below) should be co-prescribed. If H. pyloriis
present it should be eradicated.

Key points

Ulcer-healing drugs

Reduction of acidity:

• antacids;


• H 2 -blockers;


• proton-pump inhibitors;


• muscarinic blockers (pirenzapine).
  Mucosal protection:


• misoprostol (also reduces gastric acid secretion);


• bismuth chelate (also toxic to H. pylori);


• sucralfate;


• carbenoxolone (rarely prescribed).

Table 34.1:Typical triple therapy Helicobacter pylorieradication regime

Lansoprazole 30 mg bd

Amoxicillina 1 g bd all for 1 week

Clarithromycin 500 mg bd

aMetronidazole 400 mg bd if patient is allergic to penicillin.

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