What Are NSAIDs?

Nonsteroidal Anti-Inflammatory Drugs are among the most commonly used medications in the world. They relieve pain, reduce fever, and fight inflammation without the use of steroids.

Mechanism

Inhibit cyclooxygenase enzymes (COX-1 and COX-2), blocking production of prostaglandins that cause pain, inflammation, and fever.

Common Uses

Pain relief, fever reduction, arthritis (osteo and rheumatoid), menstrual cramps, headaches, musculoskeletal injuries, post-operative pain.

Key Risks

GI ulcers and bleeding, kidney function decline, cardiovascular events with long-term use, fluid retention, interactions with anticoagulants.

Examples

Ibuprofen (Advil), naproxen (Aleve), meloxicam (Mobic), aspirin, celecoxib (Celebrex — COX-2 selective).

How NSAIDs Work

When tissue is injured or irritated, the body produces prostaglandins — lipid compounds that sensitize pain receptors, cause blood vessel dilation leading to redness and swelling, and raise body temperature. Prostaglandins are synthesized by two enzymes: COX-1 and COX-2.

Traditional NSAIDs (ibuprofen, naproxen, aspirin) block both COX-1 and COX-2. COX-2 inhibition is responsible for the anti-inflammatory, analgesic, and antipyretic effects. COX-1 inhibition, however, also reduces the protective prostaglandins that line the stomach — which is why GI irritation and ulcers are significant risks with regular NSAID use.

COX-2 selective inhibitors like celecoxib were developed to reduce GI side effects by sparing COX-1. However, COX-2 selective NSAIDs carry a higher cardiovascular risk. Aspirin is unique: at low doses it irreversibly inhibits COX-1 in platelets, preventing clot formation — which is why it is used for cardiovascular protection, not primarily for pain relief.

Drugs in This Class

Ibuprofen

Advil, Motrin, Nuprin

Bayer, Ecotrin, Bufferin

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Common Side Effects Across the Class

Stomach upset, nausea, heartburn

Stomach ulcers (with prolonged use)

Fluid retention and edema

Elevated blood pressure

Headache and dizziness

Kidney function changes

Increased bleeding time

Rash or skin reactions (rare)

Important Interactions & Warnings

Warfarin and anticoagulants — NSAIDs impair platelet function and can displace warfarin from protein binding, significantly increasing bleeding risk throughout the body.
ACE inhibitors and ARBs — NSAIDs can blunt blood pressure control and worsen kidney function when combined with these antihypertensives, especially in older adults or those with existing kidney disease.
Corticosteroids — Combining NSAIDs with steroids dramatically increases the risk of GI ulceration and bleeding. Use a proton pump inhibitor as a protective measure if this combination is unavoidable.
Avoid in third trimester of pregnancy — NSAIDs can cause premature closure of the fetal ductus arteriosus and are contraindicated late in pregnancy.
Kidney disease or reduced kidney function — NSAIDs reduce blood flow to the kidneys. Use with extreme caution or avoid entirely in patients with chronic kidney disease.
Peptic ulcer disease — Active ulcers are a contraindication. A PPI should be co-prescribed if long-term NSAID use is necessary in high-risk patients.

Frequently Asked Questions

What is the difference between ibuprofen and naproxen?

Both are non-selective COX inhibitors with similar efficacy. The main difference is duration: ibuprofen lasts about 4–6 hours, while naproxen lasts 8–12 hours, making naproxen more convenient for all-day relief. Naproxen may have a slightly more favorable cardiovascular profile. Both carry GI risks with regular use.

Can I take an NSAID and acetaminophen together?

Yes — they work through completely different mechanisms, so they can generally be combined safely. NSAIDs reduce inflammation via COX inhibition; acetaminophen acts centrally on pain and temperature pathways. Alternating or combining them can improve pain control. However, always follow labeling instructions and consult your pharmacist or provider.

Are NSAIDs safe for long-term use?

Long-term NSAID use carries meaningful risks: GI ulcers, kidney injury, cardiovascular events (heart attack, stroke), and fluid retention. If chronic use is necessary, it should be under medical supervision with the lowest effective amount for the shortest necessary time, along with GI protection (typically a PPI).

Why is aspirin different from other NSAIDs?

Aspirin permanently inactivates COX-1 in platelets (platelets have no nucleus and cannot make new enzymes), creating an antiplatelet effect that lasts the full 7–10 day life of the platelet. This makes low-dose aspirin valuable for cardiovascular protection. Other NSAIDs produce reversible COX inhibition and do not provide the same durable antiplatelet effect.