Drug Uses Ranitidine is used to treat certain conditions that cause your body to make too much stomach acid (e.g., Zollinger-Ellison syndrome). It might also be used to treat ulcers of the small intestine that have not responded to other treatment. Usage Following the dosage instructions of your doctor is the best way to use any medication. If you are unsure or do not remember the instructions then you may read the medicine label for more detailed information. You may choose to take Ranitidine with a meal or without one. Drug Class and Mechanism Ranitidine is categorized as an H2-receptor blocker. It blocks the action of histamine in the stomach. Thus the amount of acid the stomach makes gets reduced. This in turn reduces heartburn and heals irritation of the esophagus, and to heal ulcers of the stomach or intestines. Missed Dose Despite your best attempts at remembering, if you still miss out on a dose, then take it as soon as you remember about it. But keep in mind that you will have to adjust your next dose by spacing it out by 4 to 5 hours. If this is not possible, then the best thing to do would be to skip the missed dose and continue with your normal dosage schedule. Never try to compensate for the missed dose by taking a double dose together. It may cause adverse effects. Storage Store Ranitidine between 68 and 77 degrees F (20 and 25 degrees C). You may also store it between 59 and 86 degrees F (15 and 30 degrees C) for a limited time. Always keep it in a cool dark place that is not directly exposed to sources of heat or moisture and sunlight. Protect it from kids and pets.