Omeprazole is an acid reducer available in over-the-counter (OTC) medicines that treat frequent heartburn (i.e., symptoms occur two or more days a week). It may be written as omeprazole or omeprazole magnesium, but it is the same active ingredient. Omeprazole is part of a group of acid reducers called proton pump inhibitors, or PPIs. It can be the only ingredient in heartburn medicines that provide long-lasting relief of symptoms, or it can be found in medicines that contain an additional active ingredient that helps with the absorption of omeprazole.

Omeprazole is approved by the U.S. Food and Drug Administration (FDA) and is safe and effective when used according to the Drug Facts label. OTC medicines containing omeprazole are not intended to provide immediate relief of heartburn symptoms. They should be taken every day for 14 days. While some people experience relief of symptoms within 24 hours, it may take one to four days for the medicine to take full effect.

  • You are taking the blood-thinning drug warfarin.
  • You are using an antifungal or anti-yeast medicine.
  • You are taking the anxiety medicine diazepam.
  • You are taking the heart medicine digoxin.
  • You are taking the immune system medicine tacrolimus.
  • You are taking the HIV infection medicine atazanavir.
  • You have had heartburn for more than three months.
  • Your heartburn is accompanied by lightheadedness, sweating, or dizziness.
  • You are experiencing chest or shoulder pain with shortness of breath; sweating; pain spreading to your arms, neck, or shoulders; or lightheadedness.
  • You have frequent chest pain, wheezing, unexplained weight loss, nausea or vomiting, or stomach pain.
  • You are pregnant or breastfeeding.
  • You are allergic to omeprazole.
  • You have trouble or pain swallowing food, are vomiting with blood, or have bloody or black stools.
  • Talk to a healthcare provider before giving an OTC medicine containing omeprazole to a child or adolescent under the age of 18.
  • Click here for more information on giving OTCs to children.
  • Your heartburn continues or gets worse.
  • You need to take the product for more than 14 days.
  • You need to take more than one course of treatment every four months.
  • You take too much. Immediately contact a healthcare provider or the poison control national helpline at 800.222.1222.