Pharmacology · Class
Nonsteroidal anti-inflammatory drugs (NSAIDs) !
Drugs that ease pain, fever and inflammation by cutting prostaglandin production. The group includes aspirin and the coxibs.
Updated 2026-11-01
What they are
Analgesic, antipyretic and anti-inflammatory drugs that inhibit the cyclooxygenases (COX-1 and COX-2). They split into nonselective agents such as ibuprofen and COX-2-selective agents (coxibs) such as celecoxib.
Mechanism of action
COX enzymes turn arachidonic acid from cell membranes into prostaglandin H2, the precursor of prostaglandins, prostacyclin and thromboxane A2. By blocking the channel through which arachidonic acid enters the enzyme, NSAIDs lower the prostaglandins that sensitize nociceptors, raise the hypothalamic set point and amplify inflammation. Most bind reversibly; aspirin acetylates the enzyme irreversibly.
Target: Cyclooxygenase 1 and 2 (COX-1/COX-2, prostaglandin H synthase)
Drugs in this class
- Acetylsalicylic acidAn NSAID that permanently blocks platelet cyclooxygenase: at low doses it prevents clots in the heart and brain; at…Cyclooxygenase 1 and 2 (COX-1/COX-2)
- IbuprofenA widely used NSAID for pain, fever and inflammation. It reversibly blocks both cyclooxygenases.Cyclooxygenase 1 and 2 (COX-1/COX-2)
- CelecoxibA COX-2-selective NSAID (a coxib): it eases pain and inflammation with less stomach damage, but does not protect…Cyclooxygenase 2 (COX-2)
- IndometacinA potent non-selective NSAID used for acute gout and to close the ductus arteriosus in premature babies; headache and…Cyclooxygenase 1 and 2 (COX-1/COX-2)
- DiclofenacA widely used NSAID for joint pain and inflammation. It is almost as COX-2 selective as celecoxib and can harm the…Cyclooxygenase 2 (COX-2), also acting on COX-1
- KetorolacAn injectable NSAID with near-opioid pain relief for severe acute pain. Total use does not exceed 5 days because of…Cyclooxygenase 1 and 2 (COX-1/COX-2)
- NaproxenA long-acting non-selective NSAID used in arthritis, acute gout and dysmenorrhoea. It can interfere with the…Cyclooxygenase 1 and 2 (COX-1/COX-2)
- MeloxicamAn oxicam NSAID that favours COX-2 at usual doses and is given once a day. It is used in osteoarthritis and rheumatoid…Cyclooxygenase 2 (COX-2), also acting on COX-1
- PiroxicamAn oxicam NSAID with a very long half-life, for osteoarthritis and rheumatoid arthritis. It takes days to stabilise…Cyclooxygenase 1 and 2 (COX-1/COX-2)
Others in the class
- naproxen
- diclofenac
- ketorolac
- indometacin
- meloxicam
- etoricoxib
Test yourself
Think of the answer, then tap the question to see it.
Why can NSAIDs precipitate acute kidney injury in a hypovolemic patient?
In hypovolemia the kidney relies on prostaglandins to dilate the afferent arteriole and maintain glomerular filtration. Blocking them constricts the arteriole and filtration falls.
Which structural difference in COX-2 do coxibs exploit to be selective?
In COX-2 a valine takes the place of an isoleucine of COX-1, opening a side pocket where the coxib's sulfonamide or sulfone group fits.
Why do coxibs increase the risk of thrombotic events?
They reduce endothelial prostacyclin (antiplatelet and vasodilating, largely COX-2 dependent) without blocking platelet thromboxane A2, which depends on COX-1. The balance tips toward thrombosis.
Which NSAID inhibits COX irreversibly, and what does that mean for platelets?
Aspirin. Because the anucleate platelet cannot make new COX-1, thromboxane A2 production stays blocked for the platelet's whole life, about 7 to 10 days.
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Pain Relievers | Analgesics | Painkillers | MedlinePlus (MedlinePlus (U.S. National Library of Medicine), 2025); Ibuprofen: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2023); eEML - Electronic Essential Medicines List (World Health Organization, 2025).
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Representative model, for educational purposes only.