Identify the mechanism of action of the drug classes that ar

Identify the mechanism of action of the drug classes that are used to treat acid-peptic disease.

Solution

The most common causes of peptic ulcers include the infection caused by the bacterium Helicobacter pylori or H. Pylori, medications that disturb the gastric mucosa, psychological pressures and irregular food habits that result in improper acid secretions that damages gastric mucosa.

The peptic ulcer disease (PUD) caused by H. pylori is treated by a combination of two different antibiotics and one antacid. The drugs include clarithromycin, metronidazole or amoxicillin and a proton pump inhibitor such as omeprazole or pantoprazole.

Some of the Drugs used in the treatment of acid-peptic by reducing the gastric acid secretion:

(I). Histamine H₂ receptor antagonists (Eg: ranitidine, nizatidine, famotidine, cimetidine)

(II). Proton pump inhibitors (Eg: omeprazole, pantoprazole, lansoprazole, rabeprazole)

(III). Anticholinergic drugs (Eg: pirenzapine, propanthezine)

Histamine H₂ receptor antagonists: These drugs act as competitive inhibitors of histamine for the H2 receptors. They can also inhibit the histamine, gastrin and acetylcholine (ACh) stimulated acid secretion by the parietal cells. All of them are well absorbed through oral route.

Diarrhoea and dizziness are occasionally reported. IV administration of H2 antagonists may cause dysrhythmias.

Proton pump inhibitors: These drugs act by the irreversible inhibition of H+/K+ ATPase pump (proton pump), which is the final step in the pathway of acid secretion. They inhibit the secretion of gastric acid from the basal cells and also food stimulated acid secretion.

These drugs are generally given through oral route, and can also be given intravenously.

As these drugs are degraded at low pH conditions, they are administered as enteric coated capsules. The unwanted affects rarely reported that include headache, diarrhoea, dizziness, rashes, mental confusion, muscle pain, gynecomastia, impotence and joint pains. .

Anticholinergic drugs: Selective M1 receptor antagonists (pirenzapine) are used in the treatment of peptic ulcer and acid reflux. They can reduce the gastric acid secretion up to 40 to 50% without noticeable side effects at therapeutic doses.