Zantac (ranitidine) belongs to a group of drugs called histamine-2 blockers. Zantac works by reducing the amount of acid your stomach produces. Zantac is used to treat and prevent ulcers in the stomach and intestines. It also treats conditions in which the stomach produces too much acid, such as Zollinger-Ellison syndrome. Zantac also treats gastroesophageal reflux disease (GERD) and other conditions in which acid backs up from the stomach into the esophagus, causing heartburn. Zantac may also be used for other purposes not listed in this medication guide.

The health and medical information provided here is for general purposes only and is not a substitute for the expertise and judgment of your physician, or other health care professional. It should not be understood to indicate that the use of this medicine is safe, appropriate or effective for you. Always consult your health care professional before using this, or any other, drug.

Using Zantac may increase your risk of developing pneumonia. Symptoms of pneumonia include chest pain, fever, feeling short of breath, and coughing up green or yellow mucus. Talk with your doctor about your specific risk of developing pneumonia.
Do not use Zantac if you are allergic to ranitidine.
Ask a doctor or pharmacist if it is safe for you to take this medicine if you have kidney disease, liver disease, or porphyria.
Heartburn is often confused with the first symptoms of a heart attack. Seek emergency medical attention if you have chest pain or heavy feeling, pain spreading to the arm or shoulder, nausea, sweating, and a general ill feeling.
Zantac granules and effervescent tablets must be dissolved in water before you take them. Your doctor may recommend an antacid to help relieve pain. Carefully follow your doctor`s directions about the type of antacid to use, and when to use it. Avoid drinking alcohol. It can increase the risk of damage to your stomach. It may take up to 8 weeks of using Zantac before your ulcer heals. For best results, keep using the medication as directed. Talk with your doctor if your symptoms do not improve after 6 weeks of treatment.

Stop using Zantac and get emergency medical help if you have any of these signs of an allergic reaction to Zantac: hives; difficulty breathing; swelling of your face, lips, tongue, or throat. Stop taking Zantac and call your doctor at once if you have a serious side effect such as:
chest pain, fever, feeling short of breath, coughing up green or yellow mucus;
easy bruising or bleeding, unusual weakness;
fast or slow heart rate;
problems with your vision;
fever, sore throat, and headache with a severe blistering, peeling, and red skin rash; or
nausea, stomach pain, low fever, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes).
Less serious Zantac side effects may include:
headache (may be severe);
drowsiness, dizziness;
sleep problems (insomnia);
decreased sex drive, impotence, or difficulty having an orgasm; or
swollen or tender breasts (in men);
nausea, vomiting, stomach pain; or
diarrhea or constipation.

Take Zantac exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended.
Your doctor may recommend an antacid to help relieve pain. Carefully follow your doctor`s directions about the type of antacid to use, and when to use it.
Do not crush, chew, or break the Zantac effervescent tablet, and do not allow it to dissolve on your tongue. The 25-milligram effervescent tablet must be dissolved in at least 1 teaspoon of water before swallowing. The150-milligram effervescent tablet should be dissolved in 6 to 8 ounces of water.
Allow the Zantac effervescent tablet to dissolve completely in the water, and then drink the entire mixture. If you are giving this medicine to a child, you may draw the liquid mixture into a medicine dropper and empty the dropper into the child`s mouth.
Zantac granules should be mixed with 6 to 8 ounces of water before drinking.
Measure Zantac liquid with a special dose-measuring spoon or cup, not a regular table spoon. If you do not have a dose-measuring device, ask your pharmacist for one.
It may take up to 8 weeks before your ulcer heals. Keep using the medication as directed and tell your doctor if your symptoms do not improve after 6 weeks of treatment.
This medication can cause unusual results with certain medical tests. Tell any doctor who treats you that you are using Zantac.
Store Zantac at room temperature away from moisture, heat, and light.