Prevacid vs Prilosec: Similarities and Differences

By Zina Semenovskaya, MD
Medically reviewed checkmarkMedically reviewed
July 12, 2022

Gastroesophageal reflux disease (GERD) affects about 20% of people in the United States.

It’s more than just heartburn or acid reflux after one meal.

GERD is a chronic, painful digestive condition that leads to health complications over time.

Prevacid and Prilosec are two medications commonly used to treat symptoms of GERD.

In this article, we’ll explore the similarities and differences between these medications, as well as common side effects, drug interactions, and important warnings to be aware of.

Prevacid vs Prilosec

Prevacid (the brand name for lansoprazole) and Prilosec (the brand name for omeprazole) are available over the counter or, if a higher dosage is needed, with a prescription.


Prevacid and Prilosec are  both proton pump inhibitors (PPIs).

They work to reduce symptoms of GERD and acid reflux by blocking how much acid the stomach produces. 

The U.S. Food and Drug Administration (FDA) has approved these medications for the same uses:

  • Gastroesophageal reflux disease (GERD)
  • Esophagitis
  • Zollinger-Ellison syndrome
  • Systemic mastocytosis
  • Duodenal and gastric ulcers


Prevacid and Prilosec have many similarities.

  • Drug class: Prevacid and Prilosec are proton pump inhibitors. They work similarly to decrease acid in the stomach.
  • Conditions treated: Both are approved for treating the same conditions, as above.
  • Time to take effect: Prevacid takes effect around 1-3 hours after it is taken, with rapid absorption after the medicine leaves the stomach. Prilosec is rapidly absorbed as well. Prilosec may take 1-4 days before the full effect is achieved, and Prevacid may take up to 4 days.
  • Length of treatment: Prevacid is typically prescribed or recommended for 10 days or up to 12 weeks, although some patients may prescribed longer courses. Prilosec is typically prescribed or recommended for 10 days or up to eight weeks, although it may be used longer in some cases.


Although Prevacid and Prilosec are similar in many ways, they have a few differences:

  • Dosages: Follow dosing instructions for the medication you are taking. Prevacid is typically 15-30 milligrams (mg), one or two times per day. Prilosec is typically 20-40 mg, one or two times per day.
  • Forms: Prilosec is available as a pill or a powder. Prevacid is available as an extended-release tablet, a dissolving tablet, and a liquid.

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Common Side Effects

Prevacid and Prilosec can each  cause some side effects, as listed below.



Drug Interactions

Prevacid and Prilosec also both have potential drug interactions, as noted below.


  • Calcium carbonate
  • Iron salts
  • Itraconazole
  • Ketoconazole
  • Atazanavir
  • Ampicillin
  • Warfarin
  • Sucralfate
  • Red yeast rice
  • St. John’s wort
  • Loop/thiazide diuretics
  • H2 blockers or other antacid medications
  • Methotrexate


  • Ampicillin
  • Calcium carbonate
  • Vitamin B12
  • Cyclosporine
  • Diazepam
  • Digoxin
  • Disulfiram
  • Flurazepam
  • Gefitinib
  • Indinavir
  • Iron salts
  • Ketoconazole
  • Phenytoin
  • Triazolam
  • Warfarin
  • Citalopram
  • Methotrexate
  • Plavix
  • St. John’s wort

Is Prevacid or Prilosec More Effective?

Prevacid and Prilosec are equally effective for the conditions they are approved to treat. 

A double-blind study of 3,510 patients compared the two drugs’ effectiveness for heartburn relief.

Prevacid was slightly more effective at relieving severe heartburn symptoms, but at the end of eight weeks, both medications performed the same.

Additionally, a meta-analysis of different PPIs found that all are comparable, and taking the right dose matters more than which medication you take for the effectiveness of a treatment. 

A healthcare provider can help determine which medication might work best for your health and medical needs.


Because Prevacid and Prilosec are in the same drug class, they have similar warnings.

Taking either one for a prolonged period of time can result in potentially serious health conditions, including:

  • Clostridium difficile diarrhea
  • Bone fracture
  • Cutaneous lupus erythematosus
  • Systemic lupus erythematosus
  • Vitamin B12 deficiency
  • Acute interstitial nephritis (a serious kidney condition)
  • Serious magnesium deficiency 

Both drugs may increase the risk of false-positive results when testing for neuroendocrine tumors.

Women who are pregnant or breastfeeding should speak with their healthcare provider before taking Prevacid or Prilosec.

People who have osteoporosis should not take these drugs, as they increase the risk of serious bone fractures.

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How K Health Can Help

Did you know you can get affordable primary care with the K Health app? Download K Health to check your symptoms, explore conditions and treatments, and if needed text with a healthcare provider in minutes. K Health’s AI-powered app is based on 20 years of clinical data.

Frequently Asked Questions

Which is better Prilosec or Prevacid?
Prilosec and Prevacid are equally effective for the conditions they treat. A medical provider can determine which medication is best for your health needs.
Is Prevacid and Prilosec the same thing?
Prevacid and Prilosec are in the same category of drugs. They are both proton pump inhibitors (PPIs) and have similar side effects, but they are not the same drug, and cannot be used interchangeably.
What is the safest drug for acid reflux?
Prevacid and Prilosec are considered safe treatments for GERD, acid reflux, and heartburn. However, certain medical conditions or medication interactions make them an unsafe choice for you. A healthcare provider can help determine the safest choice for your acid reflux treatment.

K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.

Zina Semenovskaya, MD

Dr. Semenovskaya specializes in emergency medicine, and received her medical degree from Weill Cornell Medical College. She is currently the medical director at Remote Emergency Medicine Consulting, LLC and splits her time working clinically as an emergency medicine attending in California and Alaska. She is the first of our doctors to be fluent in Russian.

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