What are NSAIDs?

NSAID stands for Non-Steroidal Anti Inflammatory Drug.  NSAIDs is usually pronounced EN-seds. They also go by the acronyms NSAIAs (non-steroidal anti-inflmmatory agents/analgesics) or NSAIMs (non-steroidal anti-inflammatory medicines). It’s a large group of common medications available under a variety of brand names.  There are a large number of different NSAIDs falling into a number of different groups.  Many are available without prescriptions, with aspirin, ibuprofen and naproxen being some of the most common.  Others are only available with a prescription.

NSAIDs are generally considered safe, but as much as 30% of people using them experience some side effects.  They don’t have many of the same adverse reactions of steroids, though.  And unlike many other painkillers, NSAIDs are not narcotic, virtually eliminating the risk of addiction (or drowsiness, based on your use of the word “narcotic”).

For more about the side effects of NSAIDs: NSAIDs Side Effects

The Three Characteristics of NSAIDs

All NSAIDs have these three basic features, to one degree or another.

Analgesic – This means that these medications have pain-relieving qualities, which is probably their most common use.  Over-the-counter NSAIDs are most often marketed as painkillers.

Anti-pyretic – Anti-pyretic drugs are those that reduce fever. NSAIDs reduce fever by interfering with a group of hormones (prostaglandins), which cause the body’s temperature to rise and result in a fever.

Anti-inflammatory – Along with fever, prostaglandins trigger inflammation or swelling. By interfering with the hormones triggering swelling, NSAIDs are able to reduce the painful swelling of a number of conditions and injuries.

How to Take NSAIDs

Most NSAIDs are taken orally in pill form. The dosage for NSAIDs varies based on the specific drug and the condition it is treating. Due to their tendency to cause stomach problems, NSAIDs should always be taken with food or a full glass of water. Taking antacids at the same time can also help alleviate some of the stomach problems. Pills are generally prescribed for widespread or internal pain (such as headaches).

They are also available as s a topical cream directly applied to a sore or injured part of the body. Researchers are uncertain whether these NSAIDs are actually more helpful in joint or muscle pain, but in one study patients did report significant improvement in their knee pain. The scientists in charge of the experiment aren’t sure whether the drugs are actually more effective, or if it’s the placebo effect at work.

How NSAIDs Work

Though there are a wide variety of NSAIDs, and their individual mechanisms can vary, they generally work in the same way. The drug stops the action of cyclooxygenase (COX), which is a key step in producing the prostaglandins mentioned earlier. No COX, no prostaglandins, and no fever or inflammation.  Obviously, this is an over-simplified version of the drug’s complex action, though.

This same action, however, also contributes to many of the more common side effects of NSAIDs. COX and prostaglandins are normal parts of a healthy body, the section on NSAID side effects for more details.

Different Groups of NSAIDs

Though their actions are similar, not all NSAIDs are the same. Many have very different chemical structures from other drugs with similar effects.  The functional  differences might include the following:

Tolerability – If someone is taking NSAIDs repeatedly, they may develop a tolerance to the drug and no longer benefit from it. As tolerance goes up, many people take more of the medication, which could lead to increased side effects or even over-dose. Doctors may instead choose to move to a different class of medication with similar effects.

Elimination half-life – Different NSAIDs take different amounts of time to process.  This is generally referred to as “half-life” or the amount of time it takes for the body to process and remove half of the medication. A longer half-life generally means longer effects, both positive and negative.

The groups of NSAIDs include:

  • Salicylates
  • Proprionic acid derivatives
  • Acetic acid derivatives
  • Enolic acid (Oxicam) derivatives
  • Fenamic acid derivatives (Fenamates)
  • Selective COX-2 Inhibitors (Coxibs)

Click here for more information about the Families of NSAIDs.


Though many of its uses are similar to NSAIDs, paracetamol (also called acetaminophen) is not an NSAID. This drug is the active ingredient in many commercial, over-the-counter painkillers, but its function is very different from NSAIDs.

Paracetamol reduces pain by effectively raising the body’s pain threshold, making it an analgesic.  It also affects the brain directly to reduce fever, which makes it an anti-pyretic.

However, paracetamol does not have any significant anti-inflammatory action, nor does it share the chemical features of NSAIDs.  Nor does it cause the stomach problems common with NSAIDs, which is often used in marketing the medication as an alternative painkiller.

NSAIDs for Animals

NSAIDs are often proscribed to animals for various kinds of pain. It is important to consult a veterinarian before administering any of these medications to animals, however, as they may have different effects on non-humans than humans taking the same medication. Not all NSAIDs are healthy for animals, and some are dangerous in certain doses. Just like with humans, it’s important to only administer medications according to the advice and instructions of a medical professional.


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