Several gastrointestinal disorders can be treated with H2 blockers. These include:

• Peptic ulcers. H2 blockers can treat two types of peptic ulcers, duodenal ulcers and gastric ulcers. They can also prevent recurrence of duodenal ulcers. H2 blockers may be used with other medications (e.g., antibiotics) to treat peptic ulcers caused by the bacteria Helicobacter pylori and to get rid of this bacteria.
  
  

  

• Gastroesophageal reflux disease (GERD). H2 blockers are typically used to treat this condition only when other lifestyle modifications, dietary changes and other medications (e.g., antacids) fail to relieve symptoms. H2 blockers provide short-term relief by raising the pH level in the stomach. Inflammation of the esophagus (esophagitis) caused by GERD may also be treated with H2 blockers.
  
  
• Hypersecretory states (states in which a bodily secretion is produced in excess). H2 blockers can be effective in treating conditions such as Zollinger-Ellison syndrome if the more powerful acid suppressant drugs (proton-pump inhibitors) are not effective or advisable. However, higher doses of H2 blockers may be required when treating a peptic ulcer. Such higher dosage levels may increase the risk of side effects associated with H2 blockers.
  
  
• Stress ulcers. H2 blockers are used to inhibit the formation of stress ulcers, a sudden form of gastritis with ulcers and hemorrhaging (sudden, uncontrollable bleeding) that may occur following burns, shock, trauma or critical illness.

Other conditions treated with these drugs include heartburn, acid indigestion and sour stomach. Patients usually use over-the-counter strengths of H2 blockers for these milder conditions.