omeprazole (Prilosec, Zegerid) - drug class, medical uses, medication side effects, and drug interactions by MedicineNet.com

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Pharmacy Author: Omudhome Ogbru, PharmD
Medical and Pharmacy Editor: Jay W. Marks, MD

GENERIC NAME: omeprazole, omeprazole/sodium bicarbonate

BRAND NAME: Prilosec, Zegerid

DRUG CLASS AND MECHANISM: Omeprazole is in a class of drugs called proton pump inhibitors (PPI) that block the production of acid by the stomach. Other drugs in the class 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. By blocking the enzyme, the production of acid is decreased, and this allows the stomach and esophagus to heal. Zegerid contains omeprazole and an antacid (sodium bicarbonate). The FDA approved omeprazole in September 1989.

GENERIC AVAILABLE: Yes (Prilosec)

PRESCRIPTION: Yes; No (Prilosec OTC, Zegerid OTC)

PREPARATIONS: Capsules: 10, 20 and 40 mg. Tablets: 20 mg (Prilosec OTC). Powder for oral suspension: 20 and 40 mg

STORAGE: Capsules should be stored at 15 to 30 C (59 to 86 F) and tablets at 20 to 25 C (68 to 77 F). They should be kept away from moisture and light.

PRESCRIBED FOR: Omeprazole is used for treating acid-induced inflammation and ulcers of the stomach and duodenum; gastroesophageal reflux disease (GERD); erosive esophagitis, heartburn; prevention of upper gastrointestinal bleeding in critically ill patients; and Zollinger-Ellison Syndrome. It also is used in combination with antibiotics for eradicating H. pylori infection of the stomach.

DOSING: 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.

DRUG INTERACTIONS: 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.