Painkillers and Your Stomach: How NSAIDs Cause Gastritis, Ulcers and Bleeding

Your knee has been aching on the stairs for months, so you keep a strip of aceclofenac in your handbag. Or your lower back flares after a long day on the two-wheeler, and the chemist hands you a diclofenac tablet “with a gastric cover”. It works, so you take another one tomorrow, and the day after. Then one morning you notice a burning feeling high in your stomach, a sour taste in the mouth, or stools that look unusually dark.

Common painkillers such as ibuprofen, diclofenac, aceclofenac and naproxen belong to a group called NSAIDs (non-steroidal anti-inflammatory drugs). They are useful medicines, but they are also one of the most frequent reasons for gastritis, stomach ulcers and bleeding from the gut. This guide explains how they affect the stomach, who is most at risk, the warning signs to watch for, safer habits, and why finding the real cause of your pain is the best protection of all.

How do painkillers damage the stomach?

Your stomach makes strong acid every day, yet it does not digest itself. The lining is protected by mucus, bicarbonate and a healthy blood supply, much of it controlled by natural chemicals called prostaglandins.

NSAIDs ease pain and swelling by blocking enzymes called COX-1 and COX-2, which make prostaglandins. Blocking COX-2 calms inflammation in a sore joint. Blocking COX-1, however, also lowers the protective prostaglandins in the stomach. The lining becomes thinner and more easily injured by acid. The tablet can also irritate the surface directly as it dissolves.

The key point many people miss: most of the damage comes from the medicine in your bloodstream, not just contact with the stomach wall. So a diclofenac injection, a suppository or a coated tablet can still harm the stomach. Gels rubbed on the skin put far less medicine into the blood and are generally gentler.

Gastritis, ulcer and bleeding: what is the difference?

• Gastritis is irritation and inflammation of the stomach lining. It can cause burning, nausea and a feeling of fullness, or no symptoms at all.
• An ulcer is an open sore that goes deeper into the wall of the stomach (gastric ulcer) or the first part of the small intestine (duodenal ulcer).
• Bleeding happens when an ulcer erodes into a blood vessel. It may be slow, causing tiredness and anaemia over weeks, or sudden and heavy.
• Perforation, a hole through the stomach wall, is rare but causes sudden, severe abdominal pain and is a surgical emergency.

Another common cause of ulcers is infection with H. pylori, a stomach bacterium that is widespread in India. When H. pylori and regular NSAID use come together, the risk of an ulcer adds up.

Who is at higher risk of painkiller ulcers?

Anyone can develop gastritis from NSAIDs. Some people are far more vulnerable, often those who need pain relief most, such as older adults with knee osteoarthritis or long-standing lower back pain.

If you take steroids for asthma, a skin problem or arthritis, you can read more about their own effects in our guide to steroid side effects. If you have had a heart attack or stroke and take blood thinners, as many people do after a stroke, please check with your doctor before taking any over-the-counter painkiller.

NSAIDs can also raise blood pressure and strain the kidneys, so people with diabetes or kidney concerns need extra care.

Warning signs that painkillers are hurting your stomach

Many people notice nothing at first. When symptoms do appear, they may include:

• Burning or gnawing pain in the upper abdomen, between the ribs, sometimes worse at night or on an empty stomach
• Acidity, heartburn, sour burps or nausea that began after starting painkillers
• Bloating, feeling full after a few mouthfuls, or loss of appetite
• Unusual tiredness, breathlessness on stairs or pale skin, which can point to slow blood loss and anaemia
• Black, sticky, tar-like stools or vomit that looks like blood or coffee grounds (these are emergencies)

Iron tablets can darken stools too, but never assume. Older adults may have no pain at all before a bleed, so “my stomach feels fine” is not proof of safety.

How doctors check and treat NSAID gastritis and ulcers

Your doctor will ask which painkillers you take, how often, for how long, and whether you also use blood thinners, steroids or alcohol. Common tests include:

• Complete blood count to look for anaemia from hidden blood loss, and iron studies if needed.
• H. pylori testing by breath test, stool test or a biopsy during endoscopy.
• Upper GI endoscopy by a gastroenterologist, when symptoms are persistent, there are warning signs, or you are older with new symptoms. It shows gastritis or ulcers directly, and bleeding vessels can often be treated during the same procedure.
• Kidney and liver function tests, since these organs also matter when choosing safer pain relief.

Treatment usually means reviewing the painkiller with your doctor, a course of acid-reducing medicine such as a proton pump inhibitor (for example omeprazole or pantoprazole), and H. pylori treatment if it is found. Most uncomplicated ulcers heal over several weeks; a bleeding ulcer needs hospital care. For stomach symptoms that do not settle, a gastroenterologist is the right specialist.

Safer habits if you need pain relief

• Never self-medicate for weeks. A few days for a sprain is one thing. If you need painkillers most days for more than a week or two, see a doctor about the cause.
• Take with food, but do not rely on it. Food and a glass of water reduce surface irritation. They do not block the effect on the stomach’s protective chemicals.
• Ask about stomach protection. If you are in a higher-risk group and your doctor feels an NSAID is still needed, they may add an acid-reducing tablet, choose a different painkiller, or use the lowest dose for the shortest time. Your doctor weighs this against your heart and kidney risks.
• Read the label. Many cold, fever and “body pain” combinations sold in India contain an NSAID. Taking one of these on top of your usual tablet doubles the dose without you realising.
• Avoid mixing with alcohol, and tell every doctor and pharmacist about your blood thinners or steroids.
• Do not stop prescribed medicines on your own. Low-dose aspirin for the heart, arthritis medicines from a rheumatologist, or steroids for a medical condition should only be changed by the doctor who prescribed them.
• Ask about gentler options. For some people paracetamol, a topical gel, heat, ice or a short spell of guided exercise is enough. Paracetamol is easier on the stomach but has its own daily limit for the liver, so follow your doctor’s dose, especially if you drink alcohol or have a fatty liver.

Why finding the cause of your pain matters most

A painkiller switches off a signal. It does not repair a worn knee, a strained back muscle or an irritated nerve. When people take tablets for months, it is usually because nobody has found, or treated, what is driving the pain. We explain this in more depth in living with chronic pain: why painkillers are not the answer.

Very often there is a treatable reason behind daily pain. It may be low vitamin D or B12, an underactive thyroid, poor sleep (see sleep and chronic pain), extra body weight loading the joints, as explained in weight and joint pain, or uric acid crystals as in gout. Pain in several joints may need to be sorted into osteoarthritis or rheumatoid arthritis. Stress and low mood can also turn up the volume of pain, as described in chronic pain and the mind.

For back pain, international low back pain treatment guidelines favour staying active and exercise over long-term tablets.

How Dr Heal can help

If stomach trouble has made you nervous about painkillers, our role is to look at the pain behind the tablets and to work with your physician or gastroenterologist where needed:

1. Find where the pain comes from. Our pain specialists take a detailed history, including every tablet you take, and examine your joints, spine, muscles and nerves.
2. Test under one roof. Our in-house laboratory and radiology, described on our facilities page, can check blood count, kidney and liver function, sugar, thyroid and vitamin levels, alongside X-rays or scans when needed. A 24-hour pharmacy is on site.
3. Treat the source without steroids. For joint, back and nerve pain, we may suggest a regenerative injection prepared by Dr Heal Pharma that contains no steroids, painkillers or antibiotics, aimed at helping the tissue heal rather than masking it. Read about regenerative medicine, our joint pain treatment and back pain treatment.
4. Support the whole body. Through functional medicine and clinical nutrition, we look at diet, weight, sleep and stress. Our guide to diet and arthritis pain is a good starting point.
5. Rehabilitate and refer. Guided exercise helps reduce the need for tablets over time. If endoscopy or specialist stomach care is needed, we help coordinate with the right gastroenterologist.

You can see all our services on the treatments page.

Frequently asked questions

Can one or two painkillers cause a stomach ulcer?

It is uncommon, but even a short course can cause gastritis in sensitive people, and a bleed can occur in someone already at high risk. The risk rises with higher doses, longer use and the risk factors listed above.

Does taking a painkiller after food protect my stomach?

Partly. Food reduces direct irritation and nausea, but NSAIDs still lower the stomach’s protective chemicals once absorbed. It is not full protection, so ask your doctor whether you need an acid-reducing tablet.

Is a diclofenac injection safer for the stomach than a tablet?

Not really. Injected NSAIDs reach the stomach lining through the bloodstream and can still cause gastritis or ulcers. Gels applied to the skin put much less medicine into the blood.

Is paracetamol safer than ibuprofen for the stomach?

Paracetamol is generally much gentler on the stomach, but it does not reduce inflammation in the same way and has a daily limit to protect the liver. Your doctor can advise the right dose for you.

I take aspirin for my heart and get acidity. Should I stop it?

No, do not stop it on your own. Low-dose aspirin protects many people from heart attack and stroke. Speak to the doctor who prescribed it; they may add stomach protection or test for H. pylori.

Where can I get help for pain that needs daily painkillers in Bengaluru?

Dr Heal Pain Cure Hospital sees patients with long-standing joint, back and nerve pain at its HSR Layout and Banashankari branches. Both are open 24 hours, with an in-house laboratory, radiology and pharmacy, and patients come from all over Karnataka.

This article is for general information and is not a substitute for a medical consultation. Please see a doctor for advice about your own symptoms, and do not stop any prescribed medicine without speaking to your doctor.