Ranitidine

Ranitidine, sold under the brand name Zantac among others, is a medication used to decrease stomach acid production. It is used in the treatment of peptic ulcer disease, gastroesophageal reflux disease, and Zollinger–Ellison syndrome. It can be given by mouth, injection into a muscle, or injection into a vein. In September 2019, the probable carcinogen N-nitrosodimethylamine (NDMA) was discovered in ranitidine products from a number of manufacturers, resulting in recalls. In April 2020, ranitidine was withdrawn from the United States market and suspended in the European Union and Australia due to these concerns. A reformulated ranitidine was approved in Australia in October 2024, and in the United States in November 2025. Common side effects include headaches, and pain or burning sensation if given by injection. Serious side effects may include cancer, liver problems, a slow heart rate, pneumonia, and the potential of masking stomach cancer. It is also linked to an increased risk of Clostridioides difficile colitis. Ranitidine is an H2 histamine receptor antagonist that works by blocking histamine, thus decreasing the amount of acid released by cells of the stomach. Ranitidine was discovered in England in 1976 and came into commercial use in 1981. It is on the World Health Organization's List of Essential Medicines.