Examples

H2 blockers (also sometimes referred to as acid reducers or H2 receptor antagonists) are available in nonprescription and prescription forms. Prescription forms are stronger than the nonprescription forms.

H2 blockers are usually taken by mouth, although some can also be given as an injection. Two doses (morning and evening) are generally recommended to control both daytime and nighttime symptoms. Doctors sometimes recommend a single dose, taken at bedtime, for people who have difficulty remembering to take their medicines.

How It Works

H2 blockers reduce the production of stomach acid. This makes the stomach juices less acidic so that any stomach juice that gets into the esophagus is less irritating. This relieves symptoms and allows the esophagus to heal.

Why It Is Used

H2 blockers are used to treat the symptoms of gastroesophageal reflux disease (GERD). They may be prescribed for your symptoms without any diagnostic testing if your symptoms indicate GERD.

• H2 blockers may be used together with antacids.
• Nonprescription H2 blockers may be used for up to 2 weeks for short-term symptom relief. But if you have been using nonprescription medicines to treat your symptoms for longer than 2 weeks, talk to your doctor. If you have GERD, the stomach acid could be causing damage to your esophagus. Your doctor can help you find the right treatment.
• Prescription H2 blockers may be used on a long-term basis to relieve persistent GERD symptoms.

How Well It Works

All of the H2 blockers in this class are about equally effective. ¹

H2 blockers completely relieve mild GERD symptoms in about 6 out of 10 people. And H2 blockers heal the damage done to the esophagus by GERD (esophagitis) in about 8 out of 10 people with mild GERD. ²

The ability of H2 blockers to help a person's symptoms depends on how severe inflammation is in the esophagus and on how strong the medicine is (nonprescription or prescription strength). H2 blockers are not as effective as proton pump inhibitors in treating moderate to severe cases of GERD that have caused inflammation or wearing away (erosion) of the lining of the esophagus (esophagitis).

Side Effects

H2 blockers have been in use since the late 1960s. H2 blockers are well-studied and are considered very safe.

Minimal side effects occur with use of H2 blockers. Side effects may include:

• Headache.
• Dizziness.
• Diarrhea.
• Constipation.
• Nausea.
• Vomiting.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

Depending on the severity of your symptoms, medicines may need to be taken every day or only occasionally when GERD symptoms occur. Long-term-often lifelong-drug treatment is usually needed for GERD symptoms that are more severe, because symptoms tend to return when drug treatment is stopped. Surgery is the only other effective option to prevent GERD symptoms from recurring.

Treatment of inflammation in the esophagus (esophagitis) with H2 blockers usually lasts 8 to 12 weeks. If H2 blockers do not help relieve the symptoms, the doctor may recommend using a proton pump inhibitor (acid blocker) instead.

Some prescription H2 blockers are available in a generic form. This may make them a more cost-effective alternative for some people. Ask your doctor about whether using a generic form of one of these drugs is right for you.

Lifestyle changes and antacids are usually tried first to treat pregnant women who have GERD. If you are pregnant and think you need something stronger, ranitidine and cimetidine are the H2 blockers that have been studied the most. They seem to be safe during pregnancy. It is still a good idea to talk to your doctor about what medicines are safe to use during pregnancy.

Complete the new medication information form (PDF)(What is a PDF document?) to help you understand this medication.

Citations

1. Katzka DA, Rustgi AK (2000). Gastroesophageal reflux disease and Barrett's esophagus. Medical Clinics of North America, 84(5): 1137–1161.

2. Vaezi MF (2007). Esophageal disorders. In DC Dale, DD Federman, eds., ACP Medicine, section 4, chap. 1. New York: WebMD.