Difference between Prilosec and Prevacid

Updated on February 15, 2018

A lot of arguments have been made about the difference between Prilosec and Prevacid. These medications are both potent treatments for heartburn, acid reflux, and other bacterial infections of the stomach. Although they come from the same family of proton pump inhibitors, one must consider a few differences before deciding to take these drugs.



Prilosec, sold under the generic name omeprazole, is a proton pump inhibitor which prevents the release of acid from the stomach. It is an effective treatment primarily for GERD (gastroesophageal reflux disease), where the backflow of acid from the stomach results in heartburn. It is also indicated for peptic ulcer and Zollinger-Ellison syndrome. Prilosec can be taken orally or intravenously and can be bought over the counter or with a prescription. It comes in the form of a 2.5mg suspension, a 10mg suspension, and 10, 20, or 40mg delayed-release capsules. Omeprazole has a rapid absorption. The most prevalent side effects of Prilosec are a headache, vomiting, nausea, and constipation. Omeprazole has been known to have a poorer percentage of bioavailability compared to Lansoprazole, which is at 30-40%.

Prevacid is a brand name for lansoprazole, a proton pump inhibitor that blocks acid production from the stomach. It is used to treat disorders such as GERD, esophagitis, Zollinger-Ellison Syndrome, and heartburns that occur two or more days a week. Prevacid is also indicated for stomach ulcers secondary to long-term NSAID use. It is an over-the-counter medication which comes as an oral suspension, orally disintegrating tablet, delayed release capsule, injectable solution, and sprinkles. The frequent side effects of Prevacid include a headache, nausea, abdominal pain, and diarrhea. Lansoprazole has a bioavailability at 80%.

Prilosec vs Prevacid

So what’s the difference between Prilosec and Prevacid? Technically, there are more similarities than differences between these two types of drugs. They both treat the same conditions and come from the same family of proton pump inhibitors. They can both be bought over the counter or with a prescription. However, they are different in their active ingredient – Prilosec containing omeprazole and Prevacid containing lansoprazole.

With regard to effectivity, both Prevacid and Prilosec inhibit acid production in the stomach significantly. However, Prevacid has been proven to be more potent over long-term use, specifically for acid reflux. Its bioavailability is also better at 80% compared to Prilosec’s 30-40%. But Prevacid is more expensive than Prilosec, costing about $38 a month. Prilosec costs approximately $10 monthly.

Comparison Chart

Active ingredient is omeprazoleActive ingredient is lansoprazole
Less potent in treating acid refluxMore effective in treating long-term acid reflux
Less absorption and bioavailabilityFaster absorption and better bioavailability
More affordableMore expensive
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