HomeDrug ClassesHistamine-2 Antagonists

Histamine-2 Antagonists: Uses, Common Brands, and Safety Info

Histamine-2 antagonists, also known as H2 blockers, are medications used to reduce stomach acid production. They are commonly prescribed for conditions such as GERD, peptic ulcers, and gastritis. Popular brands include cimetidine, ranitidine, famotidine, and nizatidine. These medications are generally safe, but side effects can include headaches and digestive issues. Serious reactions are rare.

Histamine-2 Antagonists

Histamine-2 antagonists, also known as H2 blockers, are a class of medications commonly used to decrease stomach acid production. These drugs work by inhibiting the action of histamine on the receptors found in the stomach, which ultimately reduces the amount of acid secreted by the stomach lining. Histamine-2 antagonists are primarily indicated for the treatment and prevention of conditions such as gastroesophageal reflux disease (GERD), peptic ulcers, and gastritis.

Uses of Histamine-2 Antagonists

Histamine-2 antagonists are widely used for various gastrointestinal conditions due to their ability to reduce stomach acid secretion. They are effective in relieving symptoms such as heartburn, regurgitation, and indigestion associated with GERD. These medications are also prescribed to heal and prevent the recurrence of peptic ulcers, including those caused by the bacteria Helicobacter pylori. Additionally, histamine-2 antagonists may be used in the management of gastritis, both acute and chronic.

Common Brands

There are several commonly prescribed histamine-2 antagonists available in the market. Some of the popular brand names include:

Cimetidine (Tagamet)

Cimetidine is one of the oldest and most well-known histamine-2 antagonists. It is used to treat and prevent peptic ulcers, GERD, and hypersecretory conditions such as Zollinger-Ellison syndrome. Cimetidine is available both as prescription and over-the-counter (OTC) formulations.

Ranitidine (Zantac)

Ranitidine is another commonly prescribed histamine-2 antagonist. It provides relief from symptoms of excessive stomach acid and is used for the treatment of ulcers, GERD, and pathological hypersecretory conditions. Ranitidine is available in both oral and injectable forms.

Famotidine (Pepcid)

Famotidine is a potent histamine-2 antagonist and is commonly used for the short-term relief of GERD symptoms. It is also prescribed for the prevention and treatment of peptic ulcers. Famotidine is available as both prescription and OTC medications.

Nizatidine (Axid)

Nizatidine is a histamine-2 antagonist that is primarily used for the treatment and maintenance of stomach and intestinal ulcers. It is also prescribed to manage GERD symptoms and excess stomach acid production. Nizatidine is typically available in oral formulations.


Histamine-2 antagonists are generally considered safe and well-tolerated when used as directed. However, as with any medication, there are certain precautions and potential side effects to be aware of. Common side effects of these drugs may include headache, dizziness, constipation, diarrhea, and rash. Serious adverse reactions are rare but may include confusion, hallucinations, and severe allergic reactions