H2-receptor antagonists

H2-receptor antagonists are a class of medications used to treat conditions that cause excess stomach acid. These include peptic ulcers, gastroesophageal reflux disease (GERD), and Zollinger-Ellison syndrome. By blocking the H2 receptors on the gastric parietal cells in the stomach, these drugs decrease the production of stomach acid.

Mechanism of Action

H2-receptor antagonists work by selectively blocking the histamine H2 receptors on the surface of the gastric parietal cells. Histamine is a chemical that stimulates these cells to produce acid. By blocking the action of histamine, H2-receptor antagonists reduce the volume and concentration of stomach acid, providing relief from symptoms and allowing healing of ulcers and inflammation.

Common H2-Receptor Antagonists

Some of the most commonly prescribed H2-receptor antagonists include:

• Cimetidine
• Ranitidine
• Famotidine
• Nizatidine

Each of these medications has a slightly different chemical structure, but they all work in a similar manner to reduce stomach acid.

Indications

H2-receptor antagonists are indicated for the treatment of:

• Peptic ulcer disease (PUD)
• Gastroesophageal reflux disease (GERD)
• Zollinger-Ellison syndrome, a condition where a tumor causes the stomach to produce too much acid
• Conditions requiring reduced gastric acid secretion

Side Effects

While generally well-tolerated, H2-receptor antagonists can cause side effects in some individuals. Common side effects include:

• Headaches
• Dizziness
• Diarrhea or constipation
• Fatigue
• Muscle pain

Rare but serious side effects can include:

• Confusion (especially in elderly patients)
• Arrhythmias
• Agranulocytosis (a severe decrease in white blood cells)

Drug Interactions

H2-receptor antagonists can interact with other medications, altering their absorption or effectiveness. For example, they can decrease the absorption of drugs that require an acidic environment, such as ketoconazole or itraconazole. It is important to consult a healthcare provider about potential drug interactions.

Conclusion

H2-receptor antagonists are an important class of medications for managing conditions associated with excess stomach acid. They offer relief from symptoms and promote healing of the gastrointestinal tract. However, like all medications, they must be used under the guidance of a healthcare professional to minimize side effects and interactions with other drugs.