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What is Prilosec (omeprazole)


Updated May 13, 2014

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

What is Prilosec (omeprazole)


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What Prilosec (omeprazole) Is Used For:

Prilosec is used to help treat gastric ulcers, duodenal ulcers, GERD and erosive esophagitis. Prilosec is also used to treat H. pylori (a common ulcer-causing bacteria). Over-the-counter Prilosec is also available for the treatment of frequent heartburn that occurs more than 2 times per week.

How Prilosec (omeprazole) Works:

Prilosec is a proton pump inhibitor, which helps block gastric cells that produce acid in the stomach. In GERD, ulcers and esophagitis, too much acid can be harmful to the lining of the esophagus, stomach or intestines. By reducing the amount of acid secreted into the stomach, Prilosec and other proton pump inhibitors can help minimize damage that occurs when acid levels are high.

How Prilosec (omeprazole) Is Taken:

Prilosec should be taken before meals. Capsules should be swallowed whole and not chewed. If you have swallowing difficulties, the contents of the Prilosec capsule may be mixed into applesauce or similar substances. Make sure that the pellets found within the capsule are not crushed or chewed when swallowing.

Usual doses include 20 mg once a day (sometimes may be given twice a day), 40 mg once a day, and 60 mg once a day. It is important that you follow your physician’s orders on dosing, as more Prilosec does not equal better results.

Side Effects of Prilosec:

The most common side effects of Prilosec are (listed in the order of prevalence):

  • headache
  • abdominal pain
  • nausea
  • diarrhea
  • vomiting
  • flatulence

Other side effects (listed in order of prevalence):

  • acid regurgitation
  • upper respiratory infection
  • constipation
  • dizziness
  • rash
  • weakness
  • back pain
  • cough

You should see a doctor immediately if you experience the following symptoms, which may be related to an allergic reaction. Symptoms in bold require emergency medical treatment:

  • rash, hives, or other skin reactions
  • difficulty breathing
  • wheezing
  • difficulty swallowing

Prilosec (omeprazole) and Interference With Other Medications:

You should consult your physician if you are taking any of the following medications as they can interact with Prilosec. As this list is incomplete, you should always contact your physician prior to starting a new medication. Your physician or pharmacist can run a check for interactions between your prescribed medications.

  • warfarin
  • ketoconazole
  • ampicillin
  • Valium
  • phenytoin
  • Antabuse
  • cyclosporine
  • Prograf
  • Plavix
  • Atazanavir

Before Taking Prilosec (omeprazole):

Before beginning Prilosec, you should consult your physician. Prilosec is not for acute symptoms (symptoms occurring right now) of heartburn. Rather, it is used for long-term resolution of symptoms.

If you have black stools or bright red blood in stools, you should seek medical attention rather than using Prilosec. If you are pregnant, planning to become pregnant or nursing a baby, you should consult your physician before taking Prilosec. Always have a doctor or pharmacist review you current medication list before starting a new medication.


AstraZeneca. (2008). Prilosec Prescribing Information. Accessed: June 12, 2010 from http://www.accessdata.fda.gov/drugsatfda_docs/label/2008/022056lbl.pdf

Medline Plus. (2010). Omeprazole. Accessed: June 12, 2010 from http://www.nlm.nih.gov/medlineplus/druginfo/meds/a693050.html

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