Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)

Non-steroidal anti-inflammatory drugs or NSAIDs are one of the most widely-used drugs due to their powerful analgesic effect and the fact that you can buy them over-the-counter.
Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)
María Vijande

Reviewed and approved by the pharmacist María Vijande.

Written by María Vijande

Last update: 27 May, 2022

Non-steroidal anti-inflammatory drugs are known by the acronym NSAIDs. These are drugs that, due to their mechanism of action, have several applications. For example, they can induce analgesia, lower fever and inflammation, and have an antiplatelet effect.

NSAIDs are one of the most prescribed drugs worldwide. Due to their analgesic effect, doctors prescribe them for the treatment of rheumatic pain and inflammatory and degenerative diseases. Moreover, doctors also prescribe them for migraines, toothaches, and for any inflammatory process.

Their use is widespread, even as self-medication. This is because they’re sold over-the-counter without medical supervision, with the potential risk of side effects.

Also, it’s important to note that no NSAID is better or safer than another. In this sense, you shouldn’t take one if you’re taking another prescription drug because the drugs can interact and cause problems.

The mechanism of action of non-steroidal anti-inflammatory drugs

A person taking NSAID.
NSAIDs work by blocking the production of substances that are involved in the inflammatory response.

Once the body absorbs non-steroidal anti-inflammatory drugs and they pass through the liver, they bind to a plasma protein called albumin.

This is important because, if the patient is hypoalbuminemic, the dose of the drug must be adjusted. This is because there’ll be more of the drug in the bloodstream that isn’t bound to proteins. Therefore, the effect will be greater.

Thus, the free drug fraction will trigger the effects of non-steroidal anti-inflammatory drugs. But how?

The mechanism of action of these drugs isn’t unique. Thus, they can trigger their effects in the following ways:

  • Inhibiting the cyclo-oxygenase (COX) enzyme. This is the main mechanism of action. The inhibition of this enzyme also inhibits the synthesis of prostaglandins, substances that act as mediators of inflammation.
  • Effects not mediated by prostaglandins, such as neutrophil inhibition in inflammation or the inhibition of proinflammatory mediators, such as nitric oxide induced by cytokines.
  • Apoptosis. Prostaglandins inhibit apoptosis and this could explain, at least in part, why certain NSAIDs are related to a reduced risk of some cancers.

The classification of NSAIDs

Non-steroidal anti-inflammatory drugs can be classified depending on whether they inhibit COX-2 or not. Therefore, both non-selective and COX-2 selective NSAIDs exist.

Here are some of the NSAIDs that belong to the non-selective group:

  • Salicylates. Acetylsalicylic acid or aspirin.
  • Pyrazolones. Metamizole.
  • Aminophenols. Acetaminophen or paracetamol.
  • Propionic acid derivatives. Ibuprofen.
  • Acetic acid derivatives. Indomethacin.
  • Enolic acid (oxicam) derivatives. Piroxicam
  • Anthranilic acid derivatives (fenamates). Meclofenamic acid.

Meloxicam, nimesulide, etodolac, and coxibs, such as celecoxib, are some COX-2 selective NSAIDs.

This article may interest you: The Common Classification of Painkillers

Pharmacokinetics of NSAIDs

The body rapidly absorbs these drugs. The main route of administration is oral. However, they can also be administered topically, intravenously, and rectally. Once absorbed, they reach a maximum blood concentration after between two and three hours.

Moreover, experts recommend patients to take NSAIDs along with food, since these drugs can damage the intestinal mucosa.

These drugs highly bind to the plasma protein albumin (at 95-99%). This is important because this strong bind to albumin can cause interactions with other drugs that also have this characteristic.

Also, the liver metabolizes them and some of them have active metabolites. Moreover, almost all of them have some degree of enterohepatic circulation. Once metabolized, they’re excreted by the kidneys. Thus, doctors must exercise caution in patients with kidney failure and adjust the doses.

You may like this article: Meloxicam – Everything You Need to Know

Side effects

A woman with a stomach ache.
The main side effects of NSAIDs are related to stomach discomfort, which is why patients should consume them with food.

All drugs can cause side effects after only one dose. Thus, it’s important to understand the risks and benefits of a drug before taking it.

Non-steroidal anti-inflammatory drugs produce gastrointestinal side effects. This can cause problems in the administration of these anti-inflammatory analgesics. In addition, they’re also nephrotoxic. This means that they can cause kidney problems.

The other common side effects of these drugs are:

Finally, it’s important to consult your doctor before taking any NSAIDs. Knowing its side effects and taking it as indicated is the best way to achieve therapeutic success.

All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.