Mechanisms of gastroduodenal protection by sucralfate

Article Abstract:

Sucralfate is a substance consisting of aluminum and sulfated sucrose, a chemically modified form of the common sugar. Sucralfate is very effective in both preventing and healing ulcers. It was originally thought that sucralfate acted primarily by providing a physical barrier that prevented the strong acid and powerful enzymes in the stomach juice from attacking the stomach wall. However, as more data accumulates, it becomes clear that sucralfate exerts a number of significant effects, and its precise role in the healing of a stomach ulcer is not certain. In one sense, however, it is not surprising that the mode of action of sucralfate is poorly understood, since researchers do not agree how a normal stomach avoids simply digesting itself under normal circumstances. It is recognized, however, that an important part of the stomach's protection is the mucus layer. On one side of the mucus layer is the stomach acid; on the other side are the cells lining the stomach. These cells secrete bicarbonate, which neutralizes stomach acid. The mucus provides a viscous barrier that prevents the bicarbonate from being swept away too quickly, thereby maintaining a more hospitable environment for the stomach cells. Sucralfate increases the viscosity of the stomach mucus; at the same time, sucralfate also increases the rate of bicarbonate production. Sucralfate also alters the chemical structure of the mucus produced by the stomach cells, making them less permeable by substances dissolved in water, including stomach acid. However, the actions of sucralfate also include stimulating blood flow in the stomach, which is presumably important for healing. Sucralfate increases the secretion of somatostatin, a hormone important for the protection of the stomach. Sucralfate has been shown to increase the production of compounds called prostaglandins. These substances may be of little consequence for the protection of the stomach. However, they may play a key role in the processes of healing damaged stomach tissues. Continuing research is likely to yield more insight into the mode of action of sucralfate. However, until more is known about the protection of the stomach under healthy conditions, it is unlikely that sucralfate will be completely understood. (Consumer Summary produced by Reliance Medical Information, Inc.)

Gastric mucosa

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Role of acid milieu in the gastroprotective and ulcer-healing activity of sucralfate

Article Abstract:

Sucralfate is a medication used in the treatment of peptic ulcers. Little is known, however, on the physiological mechanisms by which sucralfate works. It seems, however, that at least part of the action of sucralfate results from its adhering to the ulcer lesion itself and providing a protective barrier. Unlike some ulcer medications, sucralfate does not inhibit the secretion of stomach acid, nor does it neutralize stomach acid. Indeed, there is some suggestion that stomach acid may be necessary for sucralfate to work. Sucralfate is a chemical salt of aluminum ions and a sulfate-containing derivative of the sugar sucrose. Sucralfate is not ionized at neutral pH, but in strongly acidic conditions it ionizes; it is thought that the ions released by sucralfate are important for protecting the injured stomach lining. A study was conducted to determine the effects of acidity on the effectiveness of sucralfate in healing different types of stomach ulcers. The ulcers were experimentally induced in laboratory rats using conditions such as stress and alcohol administration. Samples of sucralfate were adjusted to pH 2.0 (very acidic) or ph 5.0 (mildly acidic) or pH 7.0 (neutral). When these samples were used to treat the experimental ulcers, it was found that in all cases, regardless of the cause of the ulcer, the more acidic sucralfate was more effective in treating the ulcer. In the case of the alcohol-induced ulcers, the most acidic sucralfate was eight times more protective and provided protection that lasted four times longer than the mildly acidic sample. The neutral sucralfate did not protect the stomach. These results indicate that the action of sucralfate is strongly dependent upon the acidity of the stomach for its protective action. (Consumer Summary produced by Reliance Medical Information, Inc.)

Models, Composition, Gastric acid

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Acid secretory responses and parietal cell sensitivity following duodenal ulcer healing with omeprazole, sucralfate, and Maalox

Article Abstract:

Duodenal ulcers result from the erosive action of stomach acids and powerful enzymes on the wall of the duodenum, the first segment of the small intestine. The physiological details of ulcer formation, as well as the healing effects of various anti-ulcer treatments, remain poorly understood. A study was conducted to examined the physiological responses of the stomach after treatment with three different types of anti-ulcer treatment. Using a long tube, researchers sampled stomach fluid from 21 patients with duodenal ulcers to determine the rate at which stomach acid was being secreted. They then injected the patients with a low dose of the hormone gastrin to observe the response of increased stomach acid secretion. After these baseline measurements were established, the patients were treated with omeprazole, sucralfate, or Maalox. Omeprazole works by inhibiting acid secretion, sucralfate works by providing a protective barrier for the ulcer, and Maalox works as an antacid, neutralizing the acid in the stomach. After the ulcers healed, the same measurements were repeated to determine the effects the different treatments had on the physiological responses of the stomach. It was found that after treatment with sucralfate, the constant acid secretion of the stomach was relatively unchanged, but the increase in stomach acid production in response to low-dose hormone treatment was reduced. Treatment with omeprazole, on the other hand, resulted in a decrease in the basal acid secretion of the stomach, that is, there was a decrease in the constant secretion of acid in the absence of any stimulation. Treatment with the antacid Maalox did not change any of the physiological measures of acid secretion. (Consumer Summary produced by Reliance Medical Information, Inc.)

Drug therapy, Omeprazole, Maalox (Medication), Parietal cells

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