Prilosec OTC has exactly the same ingredients as the prescription version of the drug. Prilosec and the rest of the proton pump inhibitors (PPIs) work by shutting off the pumps that produce acid in the stomach. The prescription version of Prilosec was one of the most popular prescription drugs sold in the United States. It is used for a variety of stomach disorders including gastroesophageal reflux (GERD) and peptic ulcers. The dose of Prilosec used depends on the condition it is being used to treat. The prescription version is available as a 10 mg, 20 mg or 40 mg capsule. Prilosec OTC was approved for sale without a prescription in June 2003 and is only available as a 20 mg tablet.
Prilosec OTC is only used for heartburn (also known as GERD) and the directions on the container are for that condition only. The prescription version of Prilosec and Prilosec OTC are exactly the same in how they work. So, 20 mg of Prilosec OTC is the same as 20 mg of prescription Prilosec. Prescription Prilosec and the generic version (called omeprazole) are much more expensive than Prilosec OTC. A 28-day supply of Prilosec OTC 20 mg will cost about $20. A 28-day supply of omeprazole 20 mg capsules will cost about $90 and the prescription version will cost about $115. I usually advise people who pay for their prescriptions themselves to switch to the OTC product.
Can J Gastroenterol. 11(8):657-60, 1997 Nov-Dec.