Prilosec (omeprazole) is one of the most widely used heartburn medications in the United States. But a growing body of research links long-term use of Prilosec and other proton pump inhibitors (PPIs) to a higher risk of stomach cancer. The attorneys at Wisner Baum represent people who took Prilosec in lawsuits against AstraZeneca, the drug's manufacturer, alleging that long-term use of omeprazole can cause gastric cancer, and that the company failed to warn patients and their doctors of the risk.
If you or someone in your family was diagnosed with stomach cancer after taking Prilosec, you may qualify for a lawsuit against the manufacturer. Wisner Baum is filing these claims nationwide. Call (310) 207-3233 or contact us for a free, confidential case evaluation.
What Is Prilosec (Omeprazole)?
Prilosec is a proton pump inhibitor (PPI), a class of drugs that sharply reduce the amount of acid the stomach produces. Its active ingredient is omeprazole. Introduced in 1989, Prilosec was the first PPI and became one of the best-selling drugs in the world. AstraZeneca developed omeprazole through a joint venture with Merck and marketed prescription Prilosec, while Procter & Gamble sells the drug over the counter as Prilosec OTC.
Doctors recommend Prilosec for GERD (gastroesophageal reflux disease, or chronic acid reflux), heartburn, and ulcers. It is available both by prescription and over the counter, in delayed-release capsules and tablets.
According to court filings, Merck earned at least $12 billion from Prilosec and Nexium sales between 2002 and 2014 through its partnership with AstraZeneca. The companies that made and marketed Prilosec — including AstraZeneca and Procter & Gamble — are the focus of the emerging Prilosec stomach cancer litigation.
Prilosec and Stomach Cancer: The Evidence
Like all PPIs, Prilosec works by shutting down acid production in the stomach. The problem, Prilosec lawsuits allege, is what happens when people use the drug long term. When acid stays suppressed, the body produces more of a hormone called gastrin, leading to a condition known as hypergastrinemia (chronically elevated gastrin). Gastrin is a growth-promoting hormone, and researchers have long recognized that sustained high levels can overstimulate certain stomach cells (called ECL cells), driving them to multiply and, over time, potentially undergo cancerous changes. Studies cited in PPI litigation show that omeprazole — the drug in Prilosec — can raise serum gastrin two- to sixfold in most patients on long-term therapy.
Scientists have described a second pathway as well: because PPIs strip away the stomach's protective acid, bacteria can overgrow in the stomach and produce nitrosamines, which are known cancer-causing compounds.
Concerns about omeprazole are not new. Prilosec lawsuits allege long-term omeprazole use produced stomach tumors in laboratory animals decades ago, and researchers warned early on that omeprazole was accepted for human use despite having induced cancer in the target organ of animal studies.
Prilosec lawsuits also point to “rebound acid hypersecretion.” When a patient stops taking the drug, acid production can surge back above normal, bringing back the very symptoms the drug was meant to treat. Lawsuits allege this creates a “dependence loop” that pushes patients into long-term use, and it is long-term use that is tied to the increased cancer risk.
Medical Research Linking Prilosec and Gastric Cancer
A substantial body of peer-reviewed research has examined the connection between long-term PPI use and stomach cancer:
- A 2006 study published in the journal Gut found that people who used PPIs for more than three years had roughly triple the risk of non-cardia gastric cancer compared to users of older H2-blocker heartburn drugs.
- A 2017 nationwide Swedish study published in BMJ Open reported that long-term “maintenance” PPI users had about three times the risk of a gastric cancer diagnosis.
- A 2018 study in Gut found that among patients who had undergone H. pylori eradication therapy, the risk of gastric cancer was more than eight times higher in those who continued daily PPI use for three or more years compared to non-users.
- A 2025 review in BMJ Open Gastroenterology found that 20 of 21 meta-analyses reported elevated gastric cancer risk. The authors concluded the evidence was “quite convincing for a potential causal association.”
Why Are People Filing Prilosec Lawsuits?
According to plaintiffs' attorneys, the drug's manufacturers knew or should have known that long-term Prilosec use was associated with gastric cancer, based on animal studies, case reports, and published research, yet failed to warn patients and their doctors.
A central allegation involves the failure of Prilosec's warning label. Prilosec lawsuits allege that:
- Neither the prescription Prilosec label nor the over-the-counter Prilosec OTC label warns that long-term use may be associated with developing stomach cancer.
- The labels fail to warn about “rebound acid hypersecretion” — the rebound surge of stomach acid that can occur when the drug is stopped, which lawsuits allege can trap patients in long-term use tied to cancer risk.
Prilosec stomach cancer lawsuits allege failure to warn, design defect, negligence, fraudulent concealment, breach of warranty, and in some cases, wrongful death. Complaints further allege that safer alternative treatments for acid reflux were available.
AstraZeneca and PPI Kidney Injury Lawsuits
This is not the first time that Prilosec and its manufacturer have faced lawsuits. However, it is important to understand the difference between the emerging stomach cancer lawsuits and earlier litigation alleging kidney injuries.
In earlier litigation, patients alleged that Prilosec and Nexium caused kidney injuries such as chronic kidney disease. The lawsuits were consolidated into a federal multidistrict litigation (MDL) in New Jersey. In October 2023, AstraZeneca agreed to pay $425 million to resolve thousands of those kidney claims involving Prilosec and Nexium.
That litigation involved a different injury — kidney damage, not stomach cancer — and it is largely resolved. The Prilosec stomach cancer lawsuits are separate, newer, and built on different scientific evidence. It is important to understand that earlier kidney settlements do not predict outcomes in stomach cancer cases. What the previous kidney litigation does demonstrate, however, is that PPI injury claims have driven a major resolution (though AstraZeneca admitted no wrongdoing and denied the allegations).
Diagnosed with stomach cancer after taking Prilosec? Call (310) 207-3233 or contact us for a free, confidential case review.
Do I Qualify for a Prilosec Stomach Cancer Lawsuit?
You may be eligible to pursue a Prilosec stomach cancer lawsuit if the following generally apply to you or a family member:
- Took Prilosec (omeprazole) or generic omeprazole — by prescription or over the counter (Prilosec OTC).
- Used the drug for a meaningful period, often about a year or longer.
- Was diagnosed with stomach or gastric cancer (such as gastric adenocarcinoma).
- Received the diagnosis within the deadline (statute of limitations) that applies in your state.
Both prescription Prilosec and over-the-counter Prilosec OTC use may qualify for a lawsuit. The only way to know whether you have a case is to have an attorney review your specific history — a free case review can tell you where you stand at no cost or obligation.
Compensation in a Prilosec Lawsuit
While no outcome can be guaranteed, plaintiffs in cases like these may be able to recover compensation for medical and cancer-treatment costs, lost wages and earning capacity, physical pain and emotional distress, and — in wrongful death cases — funeral expenses and a family's loss of their loved one's companionship. Where the evidence supports it, punitive damages may also be available in cases alleging the manufacturers acted recklessly. The value of any individual claim depends on that person's specific circumstances.
Is There a Deadline to File a Prilosec Lawsuit?
Yes. Pursuing a Prilosec lawsuit starts with a free consultation, followed by gathering your pharmacy and medical records and filing an individual claim. Each state sets a statute of limitations — a strict deadline to file, often just a few years from the date of diagnosis or from when the injury was reasonably linked to the drug. Once that deadline passes, the right to sue can be lost. Because these deadlines can be shorter than people expect, it is important to speak with an attorney as soon as you are able.
Why Choose Wisner Baum for Your Prilosec Stomach Cancer Claim
Wisner Baum has represented people harmed by dangerous drugs and defective products since 1985. The firm has earned more than $4 billion in verdicts and settlements for thousands of clients nationwide.
Our trial record includes landmark results against major manufacturers. In the Roundup litigation, managing partner R. Brent Wisner served as co-lead trial counsel in Pilliod v. Monsanto, where a California jury returned a $2.055 billion verdict (later reduced by the court). Wisner, along with attorney and partner, Monique Alarcon, filed one of the first PPI stomach cancer cases, putting a proven trial-ready team behind this emerging litigation.
Wisner Baum handles these cases on a contingency-fee basis: if we do not win your case, you do not owe us any attorney's fees.
Free Prilosec Lawsuit Case Evaluation
If you or someone in your family was diagnosed with gastric cancer or stomach cancer after taking Prilosec, you may be entitled to compensation. The pharmaceutical attorneys at Wisner Baum are reviewing these claims now. Call (310) 207-3233 or contact us for a free, confidential case evaluation online. There are no attorneys’ fees unless we win your case.
