NSAIDs for Arthritis: Stomach, Heart, and Kidney Risks

Nonsteroidal anti-inflammatory drugs, commonly called NSAIDs, remain one of the most widely used and effective treatments for arthritis pain and inflammation. Major professional guidelines strongly recommend both oral and topical NSAIDs for osteoarthritis of the knee, hip, and hand, and they play a supporting role in managing rheumatoid arthritis while slower-acting therapies take effect. But the story doesn’t end at “take ibuprofen and you’ll feel better.” The risk profile of these drugs varies dramatically depending on which NSAID you use, how long you use it, and what other health conditions you’re living with.

How NSAIDs Tame Arthritis Pain

NSAIDs work by blocking the production of prostaglandins, signaling molecules your body makes in response to tissue damage or inflammation. They do this by inhibiting cyclooxygenase enzymes, which come in two main forms.¹ COX-1 is active throughout the body and plays protective roles in your stomach lining, kidneys, and blood clotting. COX-2 ramps up at sites of inflammation and drives pain and swelling. Traditional NSAIDs like ibuprofen and naproxen block both enzymes. Selective COX-2 inhibitors like celecoxib were designed to target only the inflammation-driving enzyme, sparing the stomach-protecting one. That distinction matters enormously for side effects, as we’ll see.

What the Evidence Shows for Osteoarthritis

The strongest evidence for NSAIDs in arthritis comes from osteoarthritis, the wear-and-tear form that affects millions of people. A large network meta-analysis published in the BMJ compared dozens of pain treatments for knee and hip osteoarthritis and found that several NSAIDs cleared a high bar for meaningful pain relief. Diclofenac at higher doses, etoricoxib, and rofecoxib (now withdrawn from the market) all showed robust evidence of clinically important improvement over placebo, with over 99 percent probability of exceeding that threshold.² About three-quarters of all oral NSAID regimens tested showed statistically better results than placebo for both pain and physical function.

Multiple international guidelines have landed in the same place. The American College of Rheumatology and the Arthritis Foundation strongly recommend oral NSAIDs for osteoarthritis of the hand, hip, and knee, alongside exercise and weight loss for people who are overweight.³ The OARSI guidelines are similarly enthusiastic about topical NSAIDs for knee osteoarthritis, giving them their highest recommendation level.⁴ However, OARSI explicitly recommends against any oral NSAID for people with cardiovascular disease or frailty, a reminder that the answer to “should I take an NSAID” is always personal.

NSAIDs in Rheumatoid Arthritis and Gout

In rheumatoid arthritis, NSAIDs play a different role. They aren’t disease-modifying; they don’t slow joint destruction or alter the immune system’s attack on the joints. Instead, they’re used as a bridge, controlling pain and inflammation while disease-modifying antirheumatic drugs (DMARDs) take weeks or months to kick in.⁵ The goal is typically to use the lowest effective dose for the shortest time needed. Naproxen at full dose has shown improvement in pain, physical function, and the number of painful joints compared to placebo in this population.

For acute gout flares, NSAIDs are a standard first-line option. A Cochrane review found that people taking NSAIDs were roughly two and a half times more likely to achieve a 50 percent reduction in pain within 24 hours compared to placebo.⁶ The relief tends to come quickly, often within the first day.⁷ Most gout treatment guidelines consider NSAIDs, colchicine, and corticosteroids roughly interchangeable for acute flares, with the choice often coming down to the patient’s other health conditions.

Topical NSAIDs and When They Make Sense

If you have knee osteoarthritis, there’s a good chance your doctor will suggest a topical NSAID gel or cream before an oral one. The reasoning is straightforward: topical formulations deliver the drug directly to the joint area and produce much lower blood levels, which reduces the risk of stomach, heart, and kidney problems. A meta-analysis of eight randomized trials involving about 2,100 patients found that topical and oral NSAIDs had similar effectiveness for osteoarthritis pain relief and stiffness improvement.⁸

Every major guideline strongly recommends topical NSAIDs for knee osteoarthritis.⁹ There are limits, though. Topical NSAIDs aren’t recommended for hip osteoarthritis because the joint sits too deep beneath muscle and fat for a cream to reach it effectively. And while some guidelines conditionally recommend topical NSAIDs for hand osteoarthritis, the practical reality of rubbing gel onto multiple small finger joints throughout the day can be inconvenient, especially for people whose hand arthritis limits their grip and dexterity.

The Stomach Problem

The most well-known risk of NSAIDs is gastrointestinal damage. These drugs can cause anything from mild heartburn to peptic ulcers and life-threatening bleeding or perforation.¹⁰ Among people who use NSAIDs regularly, the rate of ulcers and ulcer complications runs about 2 to 4 percent per year. In the United States alone, NSAID-related ulcer complications have been estimated to cause over 100,000 hospitalizations and more than 16,000 deaths annually.¹¹

The GI bleeding risk isn’t uniform across all NSAIDs, though, and the differences are striking. A systematic review and meta-analysis found that celecoxib carried the lowest risk of GI bleeding among commonly used NSAIDs. Among the nonselective options, ibuprofen had the lowest significant risk, while ketorolac, a powerful NSAID sometimes given in hospital settings, had the highest risk by a wide margin.¹² Piroxicam and meloxicam also showed elevated risks. If you’re going to use an NSAID long-term, the specific one you choose matters.

Protecting Your Stomach While Using NSAIDs

For people who need a long-term NSAID, doctors often prescribe a proton pump inhibitor (PPI) alongside it. A Cochrane review of 11 trials with over 7,000 participants found that PPIs reduced the development of new ulcers by roughly 70 percent compared to placebo.¹³ PPIs also likely reduce ulcer complications, though the evidence is less precise on that point. An earlier analysis found that combining a COX-2 inhibitor with a PPI offered the greatest overall reduction in upper GI complications, more than either strategy alone.¹⁴

The OARSI guidelines formalize this: for people with gastrointestinal risk factors who need oral NSAID therapy, COX-2 inhibitors are preferred, and combining a traditional NSAID with a PPI is considered an acceptable alternative.¹⁵ Risk factors for GI complications include being over 65, having a prior ulcer history, using corticosteroids or blood thinners at the same time, and heavy alcohol use.

Cardiovascular Risks and the Rofecoxib Story

The cardiovascular safety of NSAIDs became a major public health concern after rofecoxib (Vioxx), a selective COX-2 inhibitor, was pulled from the market in 2004 due to increased heart attack rates in clinical trials. Since then, it has become clear that cardiovascular risk is not limited to COX-2 inhibitors. It’s a class-wide effect, though the size of that risk varies between individual drugs.¹⁶

Diclofenac appears to carry the highest cardiovascular risk among commonly used NSAIDs, with meta-analyses showing a significantly increased risk of vascular events compared to placebo. Naproxen has generally appeared safer from a cardiovascular standpoint; pooled analyses have not found a significant increase in vascular events with naproxen use. Ibuprofen falls somewhere in between, and large trials have found its cardiovascular risk to be at least comparable to celecoxib’s.¹⁷ This is relevant because many people assume that switching from a COX-2 inhibitor to a traditional NSAID eliminates heart risk. It doesn’t.

What NSAIDs Do to Your Kidneys

Prostaglandins help maintain blood flow to the kidneys, so blocking their production with NSAIDs can create problems. The most common kidney-related effect is acute kidney injury, which happens when reduced blood flow to the kidneys causes a temporary drop in their filtering capacity. The good news is that NSAID-related acute kidney injury is usually reversible once you stop the drug.¹⁸ The people most vulnerable are those whose kidneys already depend heavily on prostaglandin-driven blood flow to compensate for other problems, including people with heart failure, liver disease, or existing kidney disease, and those taking multiple medications.

Beyond acute injury, NSAIDs affect fluid and electrolyte balance. They cause the body to retain sodium and water, which can worsen swelling, raise blood pressure, and aggravate heart failure. They can also raise potassium levels, a concern for people already taking certain blood pressure medications. Blood pressure may rise by roughly 3 to 6 mmHg, and NSAIDs can blunt the effectiveness of common antihypertensive drugs, particularly ACE inhibitors, ARBs, and diuretics.¹⁹ For someone whose blood pressure is well controlled on medication, adding a daily NSAID can quietly undo that control.

NSAIDs and Cartilage Health

A question that naturally follows from long-term NSAID use in osteoarthritis is whether these drugs are just masking pain while the joint continues to deteriorate, or whether they might actually affect the cartilage itself. The answer depends on which NSAID you’re taking. A systematic review found that NSAIDs don’t appear to harm healthy, mature cartilage cells, but they can interfere with the process of cartilage repair and the incorporation of transplanted tissue.²⁰

More intriguing is an observational study that compared users of traditional NSAIDs with users of COX-2 inhibitors and found they had opposite effects on cartilage. People taking conventional NSAIDs had roughly three times the odds of developing new cartilage defects in the knee and greater cartilage volume loss over time, while COX-2 inhibitor users actually had decreased cartilage defect development.²¹ This is a single observational study, so it’s not definitive, but it adds another dimension to the choice between NSAID types and raises the possibility that controlling inflammation in the joint may itself protect cartilage.

The Aspirin Interaction You Should Know About

Many people with arthritis are also taking low-dose aspirin to protect their heart. This creates a specific drug interaction that is underappreciated. Nonselective NSAIDs like ibuprofen compete with aspirin for the same binding site on the COX-1 enzyme. If the NSAID gets there first, it can block aspirin from doing its antiplatelet job, effectively canceling out the heart protection aspirin is supposed to provide.²² The interaction varies by which NSAID you’re taking, the doses involved, and the timing. Ibuprofen is the most commonly cited culprit. The FDA has previously recommended that if you need both, you take aspirin at least 30 minutes before or eight hours after ibuprofen to give aspirin time to bind without competition. Celecoxib, because it doesn’t significantly block COX-1, doesn’t have this problem.

Retrospective data underscores the stakes. Among aspirin users, hospitalization rates for combined heart attack and GI events were substantially higher for nearly every NSAID compared to acetaminophen alone.²³ If you’re on aspirin for your heart, your choice of arthritis painkiller deserves a careful conversation with your doctor.

How NSAIDs Compare to Other Painkillers

A systematic review and meta-analysis comparing the major analgesic classes for osteoarthritis found that pain reduction was fairly similar across the board: acetaminophen reduced pain by about 33 percent, oral NSAIDs by about 34 percent, COX-2 inhibitors by about 37 percent, topical NSAIDs by about 41 percent, and opioids by about 35 percent.²⁴ The numbers are surprisingly close. What separates the classes is not raw painkilling power but safety, tolerability, and appropriateness for different patients. Opioids carry addiction and sedation risks. Acetaminophen is gentler on the stomach but doesn’t address inflammation. NSAIDs hit both pain and inflammation but bring their organ-specific risks. Topical NSAIDs stand out for offering similar efficacy with far fewer systemic concerns, which is why guidelines increasingly push them as a first choice for knee arthritis.

Who Should Be Especially Cautious

Older adults face a compounding of nearly every NSAID risk. Kidney function naturally declines with age. Cardiovascular disease becomes more common. The stomach lining is more vulnerable. And older people are more likely to be taking multiple medications that interact with NSAIDs, including blood thinners, blood pressure drugs, and diuretics.²⁵ This is why guidelines for people with frailty or cardiovascular comorbidities recommend against oral NSAIDs entirely, pushing instead toward topical formulations, non-drug approaches, or carefully monitored alternatives.

Genetics also influence how you process these drugs. The CYP2C9 enzyme metabolizes several common NSAIDs, and inherited variations in this enzyme can slow drug clearance, meaning the drug stays in your system longer at higher levels than intended. This raises the risk of GI bleeding and other side effects. Pharmacogenomic guidelines now recommend dose adjustments based on CYP2C9 genotype for some NSAIDs, though in practice this testing is still far from routine.²⁶

The Over-the-Counter Knowledge Gap

A striking problem is that many people using NSAIDs for arthritis don’t realize they’re taking a drug with serious risks, partly because ibuprofen and naproxen are available without a prescription. A survey of 400 patients in a rheumatology clinic found that about 69 percent were using over-the-counter NSAIDs. Nearly two-thirds of those users said they relied only on the bottle label to determine their dose, and about 13 percent were taking OTC NSAIDs without any dose determination or professional consultation at all.²⁷ OTC NSAID labels typically recommend short-term use, yet many arthritis patients take them daily for months or years. Meanwhile, they may not mention the NSAID use to their doctor, who might be unaware of the interaction with prescribed medications or the cumulative organ risk.

This is especially important because some people end up “stacking” NSAIDs without realizing it. They might take a prescription celecoxib for arthritis and then pop ibuprofen for a headache, unintentionally doubling their NSAID exposure. If you’re using any NSAID regularly, keeping your full medication list visible to every prescriber is one of the simplest protective steps you can take.

Why One NSAID Might Work When Another Doesn’t

Clinicians have long noticed that a patient who doesn’t respond to one NSAID may do well on a different one, even within the same chemical class. Clinical trial data bears this out: discontinuation rates due to lack of efficacy are several times higher than discontinuation due to side effects, suggesting many patients cycle through options before finding their fit.²⁸ The reasons for this individual variability aren’t fully understood, but they likely involve differences in drug metabolism, the specific inflammatory pathways dominating in each person’s joints, and how each drug distributes into joint tissue. The practical takeaway is that failing on one NSAID doesn’t mean NSAIDs as a class won’t work for you. Guidelines generally suggest trying two or three different NSAIDs before concluding the class is ineffective.

Genetic variation in drug-metabolizing enzymes like CYP2C9 likely plays a role here too. Someone who metabolizes a particular NSAID unusually fast may get inadequate pain relief at standard doses, while someone who metabolizes it slowly may get better relief but at the cost of more side effects.²⁹ As pharmacogenomic testing becomes more accessible, this guesswork may eventually give way to more personalized prescribing, but for now, trial and error remains the norm.