Generic Name: ranitidine (ra NI ti deen)
Brand Names: Zantac
Medically reviewed by Drugs.com. Last updated on Jun 8, 2018.
What is Zantac?
Zantac (ranitidine) belongs to a group of drugs called histamine-2 blockers. Ranitidine 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 is also used to treat gastroesophageal reflux disease (GERD) and other conditions in which acid backs up from the stomach into the esophagus, causing heartburn.
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 help 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.
Before using Zantac
Do not use Zantac if you are allergic to ranitidine.
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.
Ask a doctor or pharmacist if it is safe for you to take this medicine if you have:
liver disease; or
porphyria (a genetic enzyme disorder that causes symptoms affecting the skin or nervous system).
Ranitidine is not expected to be harmful to an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant during treatment. Ranitidine passes into breast milk. Do not take Zantac without telling your doctor if you are breast-feeding a baby.
Using ranitidine 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.
Zantac effervescent tablets contain phenylalanine. Talk to your doctor before using this form of ranitidine if you have phenylketonuria (PKU).
How should I take Zantac?
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 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 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 liquid medicine 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 medicine can affect the results of certain medical tests. Tell any doctor who treats you that you are using this medicine.
Store at room temperature away from moisture, heat, and light.
What happens if I miss a dose?
Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.
What happens if I overdose?
Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.
Overdose symptoms may include lack of coordination, feeling light-headed, or fainting.
What should I avoid?
Avoid drinking alcohol. It can increase the risk of damage to your stomach.
Zantac side effects
Stop using this medicine and get emergency medical help if you have any of these signs of an allergic reaction to Zantac: hives; difficult 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:
stomach pain, loss of appetite;
dark urine, jaundice (yellowing of the skin or eyes);
fever, chills, cough with mucus, chest pain, feeling short of breath;
fast or slow heart rate;
easy bruising or bleeding; or
problems with your skin or hair.
Less common Zantac side effects may include:
headache (may be severe);
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.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
What other drugs will affect Zantac?
Before taking Zantac, tell your doctor if you are taking triazolam (Halcion). You may not be able to use this medicine, or you may need dosage adjustments or special tests during treatment.
There may be other drugs that can interact with ranitidine. Tell your doctor about all medications you use. This includes prescription, over-the-counter, vitamin, and herbal products. Do not start a new medication without telling your doctor.
Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
Copyright 1996-2019 Cerner Multum, Inc. Version: 8.01 DDC.
More about Zantac (ranitidine)
- Side Effects
- During Pregnancy or Breastfeeding
- Dosage Information
- Patient Tips
- Drug Images
- Drug Interactions
- Compare Alternatives
- Support Group
- En Español
- 28 Reviews
- Generic Availability
- Drug class: H2 antagonists
- FDA Alerts (10)