H2 histamine antagonist

The H2 histamine antagonists are medicines used for stomach or duodenal ulcers and also for gastro-oesophageal reflux (GOR). This family of medicines contains many compounds. They all have the suffix –tidinein their international non-proprietary name.

How do the H2 histamine antagonists work?

The H2 histamine antagonists can be administered orally or by injection. They block histamine H2 receptors which are found in the parietal cells (and therefore the cells of the wall) of the stomach. They reduce the acid secretions by these cells.

Do they have side effects?

H2 histamine antagonists are generally well tolerated. Side effects may, however, develop. These include bradycardia (abnormal slowing of heart rate) or endocrine problems: galactorrhoea and gynaecomastia (breast swelling in men), or even impotence. Muscle pains, fatigues, skin rashes and headaches are also occasionally reported.... Finally there are risks of therapeutic interactions with some oral anticoagulants , benzodiazepines, beta blockers (antihypertensive agents) and some antirejection drugs.

Sources:

• Merck Manual – 4^th edition ;
• Principles of Internal Medicine, ed. TR Harrison. Flammarion.