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Prevacid, like Prilosec, fights acid secretion by blocking the final step. This so-called proton pump is prescribed for the short-term treatment of duodenal ulcer, inflammation of the esophagus due to acid splashback, and for rare conditions of abnormal acidity such as Zollinger-Ellison syndrome.

It is a delayed-release capsule that is extremely effective in reducing stomach acid. Prevacid should not be prescribed as maintenance therapy to keep ulcers from coming back.

Side Effects and Interactions

Prevacid is well tolerated and side effects are uncommon. Diarrhea, stomach ache, and nausea have been reported.

Less common were muscle weakness, rash, chest pain, constipation, gallstones, changes in blood sugar, and elevated liver enzymes. Report any symptoms or suspected reactions to your physician promptly.

Prevacid interacts with very few drugs, but some other prescription medications require acidity for absorption. Prevacid can interfere with such medicines, which include Nizoral, ampicillin, iron supplements, and Lanoxin, among others.

Vitamin B12 also requires an acid environment for absorption, and long-term use of Prevacid could result in low B12 reserves. This may have consequences for the nerves and blood. Please discuss this with your doctor.

The asthma drug theophylline also may be affected by Prevacid.

People taking acid-suppressing drugs such as Prevacid should not take enteric-coated peppermint oil. The enteric coating is designed to keep the oil from being absorbed until it reaches the more alkaline lower intestine. But when there is very little stomach acid, the enteric coating may dissolve prematurely, releasing the oil into the stomach.

Be sure to check with your pharmacist and physician about potential interactions before taking any other medication or herb in combination with Prevacid.

Special Precautions

Animal studies have shown that Prevacid is associated with a dose-related increase in stomach cancers. It is not known whether this risk also applies to humans.

In addition, because it is so effective at reducing stomach acid concentrations, patients taking this medicine have higher levels of certain microorganisms in their stomachs than would normally survive there. Scientists do not yet know whether these bacteria have negative long-term consequences.

Regular supplementation with vitamins C and E might in theory provide protection against nitrosamines produced by the bacteria.

Taking the Medicine

Prevacid should be taken before meals. These delayed-release capsules should not be opened, crushed or chewed.

If Carafate is needed, it should be taken at least 30 minutes before Prevacid.

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About the Author
Joe Graedon is a pharmacologist who has dedicated his career to making drug information understandable to consumers. His best-selling book, The People’s Pharmacy, was published in 1976 and led to a syndicated newspaper column, syndicated public radio show and web site. In 2006, Long Island University awarded him an honorary doctorate as “one of the country's leading drug experts for the consumer.” .
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I have a friend who takes prevacid. He is anemic and has low testosterone. Could this the side effects of the prevacid?

My Grandson 10.5 Years of age has just been put on Prevacid. He is to take it at night before he goes to bed. No mention of after a meal by his Dr. This child also has Asthma and has been taking allergy shots -every 4 weeks, using Nasonex, and an inhaler daily. When necessary he also uses a steroid inhaler. This child has always had a problem with his stomach. Has never eaten much at a time, but he does eat often. Is Prevacid used in children this age on a regular basis? Could any of his Asthma medicine affect his stomach?

I have been taking Prevacid 30 mg for 12 years. About 3 years ago I developed Peripheral Neuropathy in my right foot. Both my internist & I believe it was caused by the Prevacid not allowing the body to absorb Vitamin B-12. I went off Prevacid & tried many other brands only to find that they did not work. I am back on Prevacid & get monthly shots of Vitamin B-12.

Diarrhea is a side effect of Prevacid. Although I have taken Prevacid for 5 years, daily sudden diarrhea has been a new condition in the last year. I need a recommendation for how and when to take this medication so this problem can be minimized.

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