NSAIDs like ibuprofen and aspirin are the most common medications that cause gastritis, but they’re far from the only ones. Corticosteroids, blood thinners, iron supplements, certain cancer drugs, and even proton pump inhibitors (the very drugs used to treat stomach problems) can all inflame or damage the stomach lining. The risk depends on which drug you’re taking, how long you’ve been on it, and whether you’re combining multiple offenders.
NSAIDs: The Most Common Culprit
Nonsteroidal anti-inflammatory drugs are responsible for the majority of drug-induced gastritis cases. This group includes over-the-counter staples like ibuprofen (Advil, Motrin), naproxen (Aleve), and aspirin. These drugs work by blocking enzymes called COX-1 and COX-2, which reduces pain and inflammation. The problem is that COX-1 also helps maintain the stomach’s protective mucus barrier. When both enzymes are suppressed simultaneously, the stomach lining loses its defense system and becomes vulnerable to acid damage.
Short-term use for occasional pain rarely causes problems. The risk climbs significantly when you take NSAIDs regularly for weeks or months. In one study of patients on daily low-dose aspirin (just 100 mg), nearly 43% showed signs of gastric mucosal injury on endoscopy, including erosions, hemorrhagic gastritis, or ulcers. That’s a striking number for a dose many people take without a second thought.
Selective COX-2 inhibitors like celecoxib (Celebrex) were designed to spare the stomach by targeting only COX-2. A large trial published in the New England Journal of Medicine involving over 24,000 patients confirmed that celecoxib caused significantly fewer gastrointestinal events than either ibuprofen or naproxen. It’s a safer option for the stomach, though not risk-free.
Corticosteroids Multiply the Risk
Oral corticosteroids like prednisone are widely prescribed for inflammatory conditions, autoimmune diseases, and allergic reactions. On their own, their risk to the stomach is modest. One large study found that corticosteroid users who weren’t also taking NSAIDs had essentially no increased risk of peptic ulcer disease compared to non-users.
The danger spikes when corticosteroids are combined with NSAIDs. People taking both drugs together face a risk of peptic ulcer disease roughly 15 times greater than people taking neither. That’s not a small increase. If you’re on a corticosteroid and also reaching for ibuprofen or naproxen for pain relief, that combination deserves a conversation with your prescriber.
Iron Supplements
Oral iron tablets, commonly prescribed for anemia, can directly irritate and inflame the stomach lining. The mechanism is straightforward: when iron changes from one chemical state to another inside the stomach, it generates a reaction that damages the surface cells. This is sometimes called “iron pill gastritis,” and it’s underdiagnosed because the symptoms (nausea, stomach pain, bloating) overlap with the side effects people already expect from iron.
The damage shows up as visible erosions and dark deposits of iron in the stomach tissue on biopsy. Taking iron with food can reduce the irritation, though it also reduces absorption. If iron pills cause persistent stomach symptoms, liquid formulations or lower doses taken every other day are alternatives worth discussing.
Blood Thinners and Anticoagulants
Anticoagulants are among the most commonly prescribed drugs worldwide, and they carry their own gastric risks. While they don’t damage the stomach lining in the same direct way NSAIDs do, they can worsen bleeding from any existing irritation or erosion. For someone whose stomach lining is already compromised, even mildly, adding a blood thinner turns a minor problem into a potentially serious one. This is especially relevant for people on combination therapy with aspirin and another anticoagulant.
Cancer Treatments
Chemotherapy drugs target rapidly dividing cells, and the cells lining your stomach and intestines divide faster than almost any other tissue in the body. That makes the gut a prime casualty of cancer treatment. Drugs like 5-fluorouracil, irinotecan, and platinum-based agents (cisplatin, for example) all cause direct damage to the stomach and intestinal lining.
The injury follows a predictable pattern. These drugs kill the stem cells deep in the stomach lining that normally replenish the surface. Without that renewal, the protective barrier breaks down, ulcers can form, bacteria can invade the damaged tissue, and inflammation cascades. This is part of what oncologists call mucositis, and it’s one of the most common dose-limiting side effects of chemotherapy. Newer immunotherapy drugs called immune checkpoint inhibitors can also trigger gastritis through a different pathway, by essentially turning the immune system against the stomach lining.
Bisphosphonates for Osteoporosis
Bisphosphonates like alendronate (Fosamax) are prescribed to prevent bone fractures in people with osteoporosis. These pills can cause severe irritation to the upper digestive tract, particularly the esophagus and stomach, if they aren’t taken correctly. The FDA label for alendronate carries specific instructions that exist entirely to minimize this risk: take the tablet first thing in the morning with a full glass of plain water (6 to 8 ounces), at least 30 minutes before any food, drink, or other medication, and do not lie down for at least 30 minutes afterward.
These aren’t casual suggestions. People who lie down after taking the pill, swallow it with too little water, or take it at bedtime have a significantly higher rate of esophageal and gastric injury. If you develop new stomach pain, heartburn, or difficulty swallowing while on a bisphosphonate, those symptoms shouldn’t be ignored.
Proton Pump Inhibitors: A Paradox
PPIs like omeprazole (Prilosec) and pantoprazole are the go-to treatment for acid reflux and gastritis itself. So it may seem contradictory that long-term PPI use can cause structural changes to the stomach lining. With prolonged use over months or years, PPIs can lead to alterations in the gastric mucosa that are visible on biopsy. These changes are generally mild, but they place PPIs on the list of drugs that can affect stomach tissue, particularly when taken indefinitely without a clear ongoing need.
How Symptoms Typically Develop
Drug-induced gastritis doesn’t always announce itself dramatically. Symptoms often build gradually, especially with medications taken long-term. The most common signs include upper stomach pain or burning, a persistent feeling of fullness, nausea, bloating, heartburn, loss of appetite, and belching. Some people experience vomiting. In more serious cases, erosions in the stomach lining can bleed, showing up as dark or tarry stools, vomiting material that looks like coffee grounds, or unexplained anemia.
With NSAIDs, stomach damage can be present even without noticeable symptoms. Many people have significant erosions discovered incidentally during an endoscopy done for other reasons. This is one reason why protective strategies matter for high-risk patients, not just those who feel something is wrong.
Reducing Your Risk
If you need to stay on an NSAID long-term, current guidelines recommend adding a daily proton pump inhibitor if you have risk factors for stomach complications. Those risk factors include a history of stomach ulcers or GI bleeding, being over 65, taking high doses of NSAIDs, or combining NSAIDs with corticosteroids or blood thinners. For people who’ve had a bleeding ulcer and must continue anti-inflammatory treatment, the recommended approach is a COX-2 selective drug at the lowest effective dose combined with a daily PPI.
Beyond medication adjustments, practical steps help. Take NSAIDs with food when possible. Use the lowest dose for the shortest time that controls your symptoms. If you’re on iron supplements, spacing doses further apart or switching formulations can reduce stomach irritation. And if you’re on a bisphosphonate, following the specific dosing instructions precisely is the single most effective way to protect your stomach and esophagus.