NSAIDs, or nonsteroidal anti-inflammatory drugs, are used to relieve pain, reduce fever, and fight inflammation. They’re among the most widely used medications in the world, available both over the counter and by prescription, and they treat everything from a simple headache to chronic arthritis.
How NSAIDs Work
Your body produces chemicals called prostaglandins whenever tissue is damaged or irritated. Prostaglandins trigger inflammation, pain, and fever as part of your immune response. NSAIDs work by blocking the enzymes (called COX-1 and COX-2) that your body needs to make prostaglandins. With fewer prostaglandins circulating, you get less swelling, less pain, and lower fever.
Most common NSAIDs, like ibuprofen and aspirin, block both COX-1 and COX-2 without distinction. That broad action is what makes them effective, but it’s also what causes some of their side effects, since COX-1 plays a protective role in the stomach lining. Prescription options like celecoxib (Celebrex) target COX-2 more selectively, which can reduce the risk of stomach problems.
Common Uses
The three core jobs of NSAIDs are reducing pain, lowering fever, and controlling inflammation. That makes them useful for a wide range of conditions:
- Arthritis: Both osteoarthritis and rheumatoid arthritis involve chronic joint inflammation. NSAIDs are a first-line treatment for managing the pain and stiffness of both conditions.
- Muscle and joint injuries: Sprains, strains, and tendinitis all involve swelling. NSAIDs help more than plain pain relievers here because they address the inflammation directly.
- Menstrual cramps: Prostaglandins drive the uterine contractions that cause period pain. Blocking their production is why ibuprofen works so well for cramps, often at doses of 400 mg every four hours as needed.
- Headaches and migraines: Over-the-counter ibuprofen or naproxen can effectively treat tension headaches and mild to moderate migraines.
- Fever: Any NSAID will lower a fever, making them a common choice during colds and the flu.
- Dental pain: NSAIDs are frequently recommended after dental procedures because of the combination of pain relief and inflammation control.
- Gout flares: Prescription-strength NSAIDs like indomethacin are often used to treat the intense inflammation of a gout attack.
There’s also growing evidence that regular NSAID use may have a preventive effect against colorectal cancer, though this isn’t a standard reason to take them given the risks of long-term use.
NSAIDs vs. Acetaminophen
Acetaminophen (Tylenol) relieves pain and reduces fever, but it does not treat inflammation. That’s the key difference. If you have a headache or a fever with no significant swelling, acetaminophen and NSAIDs work about equally well. But for conditions that involve inflammation, like a swollen ankle, arthritis flare, or menstrual cramps, NSAIDs are the better choice because they target the underlying swelling that acetaminophen simply can’t touch.
On the other hand, acetaminophen is easier on the stomach and doesn’t carry the cardiovascular warnings that NSAIDs do, so it’s sometimes the safer pick for people who need long-term pain management without an inflammatory component.
Common Over-the-Counter and Prescription NSAIDs
You likely already have an NSAID in your medicine cabinet. The most common over-the-counter options are:
- Ibuprofen (Advil, Motrin): Works quickly, typically taken every four to six hours. Good all-purpose choice for pain and inflammation.
- Naproxen sodium (Aleve): Lasts longer than ibuprofen, so you take it less frequently. Often preferred for sustained pain like arthritis or back pain.
- Aspirin (Bayer): The oldest NSAID, also used in low doses (81 mg) to reduce the risk of heart attack and stroke in certain people.
Prescription-strength NSAIDs include celecoxib (Celebrex), diclofenac (Voltaren, also available as a topical gel), indomethacin, and ketorolac (Toradol), which is one of the strongest NSAIDs and is typically used for short-term acute pain.
Side Effects and Risks
NSAIDs are safe for most people when used at recommended doses for short periods. But they do carry real risks, especially with prolonged use. The FDA requires all prescription NSAIDs (except aspirin) to carry a boxed warning about two categories of risk.
The first is gastrointestinal damage. Because NSAIDs block COX-1, which helps maintain the protective lining of your stomach, they can cause stomach ulcers and serious GI bleeding. This risk increases the longer you take them and is higher in older adults. Taking NSAIDs with food or using a COX-2 selective option like celecoxib can help reduce this risk.
The second is cardiovascular events. Non-aspirin NSAIDs can increase the risk of heart attack and stroke, particularly at higher doses or with long-term use. Over-the-counter NSAIDs also carry revised labeling to make these risks clearer to consumers. Aspirin is the exception here; low-dose aspirin is actually used to protect against cardiovascular events in some people.
NSAIDs can also affect kidney function. They reduce blood flow to the kidneys, which is usually harmless in healthy people taking normal doses but can become a problem if you’re dehydrated, have existing kidney issues, or take them frequently over a long period.
Who Should Avoid NSAIDs
Certain groups face higher risks. The FDA warns against NSAID use at 20 weeks of pregnancy or later because these drugs can cause kidney problems in the developing baby, leading to dangerously low amniotic fluid levels. After 30 weeks, the risk increases further because NSAIDs can cause premature closure of a blood vessel in the baby’s heart. The one exception is low-dose aspirin (81 mg), which is sometimes prescribed during pregnancy for specific conditions like preeclampsia prevention.
Children and teenagers should never take aspirin during a viral illness like the flu or chickenpox. Aspirin use during these infections is linked to Reye’s syndrome, a rare but potentially fatal condition that causes swelling in the liver and brain. Symptoms typically appear three to five days after the viral infection begins. Ibuprofen, however, is considered safe for children at appropriate doses.
People with a history of stomach ulcers, uncontrolled high blood pressure, heart failure, or chronic kidney disease should also use caution and may need to avoid NSAIDs entirely or use them only under close guidance. Some people with asthma experience worsened symptoms from NSAIDs, a reaction that affects roughly 10 to 20 percent of adults with asthma.
How Long You Can Safely Take Them
For occasional use, like a few days of ibuprofen for a pulled muscle or naproxen during your period, the risks are minimal for most healthy adults. The standard over-the-counter dose of ibuprofen for pain is 400 mg every four to six hours as needed. For chronic conditions like arthritis, prescription doses run higher, up to 3,200 mg of ibuprofen per day divided into multiple doses, but these regimens require medical oversight.
The general principle is to use the lowest effective dose for the shortest time necessary. If you find yourself reaching for ibuprofen or naproxen daily for more than a week or two, that’s worth a conversation with your doctor, both to manage the risks of the NSAID itself and to investigate what’s causing the ongoing pain.