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Zantac is the brand name for ranitidine, a medication that reduces acid production in the stomach. It is used to help prevent or treat conditions caused by excessive amounts of acid, such as ulcers in the small intestine or stomach. Zantac also helps treat gastroesophageal reflux, a condition in which stomach acid backs up into the esophagus, producing inflammation and heartburn. Zantac acts by blocking the action of histamine at histamine H2-receptors located on the surface of the stomach cells that produce acid. It is available over-the-counter or by prescription. Zantac is generally very safe but may produce side effects with long-term use.

Is This an Emergency?

If you are experiencing serious medical symptoms, seek emergency treatment immediately.

Risk of Pneumonia

Long-term use of Zantac may increase the likelihood of developing pneumonia. A study reported in the September 2011 issue of “World Journal of Methodology” analyzed the combined results of several previously published studies. It found that long-term use of medications that block histamine H2-receptors -- called H2 blockers -- slightly increased the chances of having pneumonia. People taking H2 blockers were about 1.2 times more likely to develop pneumonia than people not taking these medications. The increased risk may be due to overgrowth of bacteria that would normally be killed by stomach acid. These bacteria then travel to the lungs to cause pneumonia. Chest pain, shortness of breath, coughing and a fever are typical symptoms of pneumonia.

  • Long-term use of Zantac may increase the likelihood of developing pneumonia.
  • The increased risk may be due to overgrowth of bacteria that would normally be killed by stomach acid.

Low Magnesium

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Using Zantac for a prolonged time may lead to low levels of magnesium. A study published in the November 2015 issue of the “American Journal of Kidney Diseases” found that people taking H2 blockers were about 2 times more likely to have low blood magnesium levels than people not taking these medications. The low levels are likely due to decreased absorption of magnesium from the digestive tract because of the reduced acidity. Low magnesium levels can produce muscle cramps, tremors, anxiety, irregular heart rhythms and seizures.

  • Using Zantac for a prolonged time may lead to low levels of magnesium.
  • The low levels are likely due to decreased absorption of magnesium from the digestive tract because of the reduced acidity.

Male Infertility

Long-term use of Zantac may reduce fertility in men. A study published in the December 2014 issue of the “Turkish Journal of Medical Sciences” noted that infertile men were almost 3 times more likely to be taking Zantac than men with normal fertility 1. On the other hand, an earlier study reported that Zantac did not affect sperm. Because of these opposite results, a review article published in “Basic and Clinical Pharmacology and Toxicology” in August 2015 concluded that it remains unclear whether Zantac affects sperm and male fertility 4. The article did note that cimetidine, an older H2 blocker that has been more thoroughly studied, does seem to reduce the number of sperm and their ability to move.

Other Side Effects

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Zantac can be accompanied by a number of serious, but rare, side effects. Because of their rarity, they are not well studied and it is unclear whether they occur with long-term or short-term use.

Warnings and Precautions

Sometimes chest pain caused by a heart problem is mistaken for heartburn and treated with Zantac. Before taking Zantac, talk to your doctor about your symptoms. Seek prompt medical care if you develop chest pain that is not your typical heartburn pain, especially if it is a pressure or heavy feeling, extends into the left arm or neck or is accompanied by nausea, sweating or dizziness.

Discuss all medications and supplements with your doctor before starting Zantac, as Zantac can interact with many of these. Limit or avoid all alcohol while taking Zantac, as Zantac can increase blood levels of alcohol, causing you to become drunk quickly and increasing your chances of developing alcohol-related disorders such as liver disease. Kidney or liver disease can reduce your body's ability to excrete Zantac, causing the drug to accumulate. If you have one of these disorders, ask your doctor whether you should take a lower than normal dose of Zantac. Avoid Zantac if you have a rare blood disease called acute intermittent porphyria, as Zantac may trigger a porphyria attack.

Reviewed by: Mary D. Daley, MD

  • Sometimes chest pain caused by a heart problem is mistaken for heartburn and treated with Zantac.
  • If you have one of these disorders, ask your doctor whether you should take a lower than normal dose of Zantac.
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