Ranitidine is both an over-the-counter and a prescription medication used to treat conditions of the stomach, esophagus, and intestines. The over-the-counter form is used to treat heartburn, acid indigestion, and sour or upset stomach. The prescription form is used to treat ulcers, GERD, erosive esophagitis, and other conditions. This medication page refers to the prescription form of ranitidine. 

Ranitidine belongs to a group of drugs called H2 blockers. It works by decreasing the amount of acid produced in the stomach.

This medication comes in regular tablet, effervescent tablet, capsule, and syrup forms. Ranitidine is taken by mouth, up to 4 times a day. This medication is also available in an injectable form to be given directly into a vein (IV) or muscle (IM) by a healthcare professional. 

Common side effects of ranitidine include headache, diarrhea, and constipation.  Ranitidine can cause dizziness and drowsiness.  Do not drive or operate machinery until you know how ranitidine affects you.