Prilosec vs. Zantac

  • Medical Editor: John P. Cunha, DO, FACOEP
    John P. Cunha, DO, FACOEP

    John P. Cunha, DO, FACOEP

    John P. Cunha, DO, is a U.S. board-certified Emergency Medicine Physician. Dr. Cunha's educational background includes a BS in Biology from Rutgers, the State University of New Jersey, and a DO from the Kansas City University of Medicine and Biosciences in Kansas City, MO. He completed residency training in Emergency Medicine at Newark Beth Israel Medical Center in Newark, New Jersey.

What are the differences between Prilosec and Zantac?

  • Prilosec (omeprazole) and Zantac (ranitidine) are for the treatment of conditions such as ulcers and gastroesophageal reflux disease (GERD) caused by stomach acid. Both drugs work in different ways to reduce stomach acid.
  • Prilosec and Zantac are both available over-the-counter (OTC).
  • Prilosec is a proton pump inhibitor (PPI) that blocks the production of acid by the stomach. Zantac works differently. It is an H2 (histamine-2) blocker that inhibits the action of histamine on the cells, thus reducing the production of acid by the stomach.
  • Common side effects of Prilosec and Zantac that are similar include diarrhea, headache, nausea, and vomiting.
  • Side effects of Prilosec that are different from Zantac include rash and dizziness.
  • Side effects of Zantac that are different from Prilosec include constipation, fatigue, and insomnia.

What are Prilosec and Zantac?

Prilosec (omeprazole) is in a class of drugs called proton pump inhibitors (PPIs) that block the production of acid by the stomach. Other PPIs include lansoprazole (Prevacid), rabeprazole (Aciphex), pantoprazole (Protonix), and esomeprazole (Nexium). Proton pump inhibitors are used for the treatment of conditions such as ulcers, gastroesophageal reflux disease (GERD) and the Zollinger-Ellison syndrome, which are all caused by stomach acid. Omeprazole, like other proton-pump inhibitors, blocks the enzyme in the wall of the stomach that produces acid so the production of acid is decreased, allowing the stomach and esophagus to heal.

Zantac (ranitidine) is in a class of drugs called H2 (histamine-2) blockers that blocks the production of acid by acid-producing cells in the stomach. Other H2 blockers include cimetidine (Tagamet), nizatidine (Axid), and famotidine (Pepcid). Histamine is a naturally-occurring chemical that stimulates cells in the stomach (parietal cells) to produce acid. H2-blockers inhibit the action of histamine on the cells, thus reducing the production of acid by the stomach, which helps prevent and heal acid-induced inflammation and ulcers.

What are the side effects of Prilosec and Zantac?

Prilosec

Omeprazole like other PPIs is well-tolerated. The most common side effects are:

Other important side effects include:

Each packet of Zegerid powder for oral suspension contains 460 mg of sodium and each capsule contains 304 mg of sodium. This should be taken into consideration in patients who need a sodium restricted diet.

Proton pump inhibitors may increase the risk of Clostridium difficile infection. High doses and long-term use (1 year or longer) may increase the risk of osteoporosis-related fractures of the hip, wrist, or spine. Prolonged use also reduces absorption of vitamin B12 (cyanocobalamin).

Long-term use of PPIs has also been associated with low levels of magnesium (hypomagnesemia). Analysis of patients taking PPIs for long periods of time showed an increased risk of heart attacks.

Therefore, it is important to use the lowest doses and shortest duration of treatment necessary for the condition being treated.

Zantac

Minor side effects occur and these are:

Other important, but rare, side effects include:

What is the dosage of Prilosec vs. Zantac?

Prilosec

For ulcers, GERD, erosive esophagitis and eradication of H. pylori the recommended dose for adults is 20-40 mg daily. Ulcer healing usually occurs within 4-8 weeks.
H. pylori infections are treated for 10-28 days.

The usual dose for prevention of upper gastrointestinal bleeding in critically ill patients is 40 mg daily for 14 days.

Prilosec OTC is used for treating heartburn for up to two weeks, and the usual dose is 20 mg daily.

For the management of Zollinger-Ellison Syndrome the starting dose for adults is 60 mg daily, and the dose is adjusted based on either the response of symptoms or the actual measurement of acid production. Doses greater than 80 mg should be divided. Doses up to 120 mg three times a day have been used in the treatment of Zollinger-Ellison Syndrome.

For maximal efficacy, omeprazole tablets should be taken before meals, swallowed whole and should not be crushed, chewed or opened.

Zantac

Ranitidine may be taken with or without food.

  • Usual oral doses for treating ulcers and GERD are 150 mg twice daily or 300 mg at bedtime. The maintenance dose is 150 mg daily.
  • Erosive esophagitis is treated with 150 mg 4 times daily.
  • Zollinger Ellison syndrome may be treated with as much as 6 g daily.
  • Heartburn is treated with 75 mg or 150 mg once or twice daily 30-60 minutes before consuming meals or beverages that cause heartburn.

Self-medication should not last longer than 2 weeks unless advised by a physician.

What drugs interact with Prilosec and Zantac?

Prilosec

Omeprazole potentially can increase the concentrations in blood of diazepam (Valium), warfarin (Coumadin), and phenytoin (Dilantin) by decreasing the elimination of these drugs by the liver.

The absorption of certain drugs may be affected by stomach acidity. Therefore, omeprazole as well as other PPIs reduce the absorption and concentration in blood of ketoconazole (Nizoral) and increase the absorption and concentration in blood of digoxin (Lanoxin). This may reduce the effectiveness of ketoconazole or increase digoxin toxicity.

Through unknown mechanisms, omeprazole may increase blood levels of saquinavir and reduce blood levels of nelfinavir and atazanavir, drugs that are used for treating patients with infection caused by the human immunodeficiency virus (HIV). Accordingly, the dose of saquinavir may need to be reduced to avoid toxicity, and the doses of nelfinavir and atazanavir may need to be increased to maintain efficacy.

Clopidogrel (Plavix) is converted to its active form by enzymes in the liver. Omeprazole reduces the activity of these enzymes and potentially can reduce the activity of clopidogrel. Omeprazole should not be used with clopidogrel.

Omeprazole increases the concentration of cilostazol (Pletal). The dose of cilostazol should be reduced from 100 mg twice daily to 50 mg twice daily when given with omeprazole.

Omeprazole may increase blood levels of methotrexate (Rheumatrex, Trexall) and tacrolimus (Prograf).

Zantac

Ranitidine, like other drugs that reduce stomach acid, may interfere with the absorption of drugs that require acid for adequate absorption. Examples include iron salts (for example iron sulphate), itraconazole (Sporanox), and ketoconazole (Nizoral, Extina, Xolegel, Kuric).

Are Prilosec and Zantac safe to use while pregnant or breastfeeding?

Prilosec

Use of omeprazole in pregnant women has not been adequately evaluated. Omeprazole should be used during pregnancy only if the benefits justify the unknown risks.
Omeprazole is excreted in breast milk and potentially could cause adverse effects in the infant.

Zantac

There are no adequate studies of ranitidine in pregnant women. Available evidence suggests that there is little risk when used during pregnancy.

Ranitidine is secreted into human breast milk and may pose a potential risk to the infant.

Summary

Prilosec (omeprazole) and Zantac (ranitidine) are for the treatment of conditions such as ulcers and gastroesophageal reflux disease (GERD) caused by stomach acid. Both drugs work in different ways to reduce stomach acid; one is a proton-pump inhibitor and the other is an H2 blocker.

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Medically Reviewed on 11/1/2017
References
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