Nonsteroidal anti-inflammatory drugs are medications that relieve or reduce pain. The best-known examples of this group of drugs are aspirin and ibuprofen.
Nonsteroidal anti-inflammatory drugs (NSAIDs) also come under the wider definition of non-opioid analgesic. This means they are a separate type of painkiller from opioid drugs such as morphine that are typically used for more severe types of pain.
NSAIDs are usually taken for less severe types of pain that result from various problems involving aches and pains. They are a different group of drugs to those used to treat nerve pains or migraines.
This article will explain what NSAIDs do, how they work, and what they are for.
Contents of this article:
Fast facts on NSAIDs
The following are selected summary points about NSAIDs - further detail is on offer in the article.
- Many NSAIDs are available over the counter - they are generally safe as long as they are used according to the labels, but they can have side effects
- NSAIDs may be preferable for cramps, aches and pains, or pain problems involving fever or swelling
- There are risks in regularly taking NSAIDs over a long period, and so patients should seek medical advice for long-term pain complaints
- Whether there is an alternative to NSAIDs depends on the reason for taking them - other options can include changes to work routines, more physical activity, and psychological help
- Headaches can become a problem for which it is helpful to seek medical advice, and for which alternatives to taking NSAIDs too often can be important.
What are NSAIDs?
In American English, "NSAIDs" is pronounced in two syllables. The first syllable for "N" and the second for "AIDs" but beginning with an "S." The pronunciation in full is "En-sAIDs." In U.K. English, three syllables are used - "En-Ess-AIDs."
Heat, swelling, and fever can be linked to some of the pains treated with NSAIDs.
Heat, redness, swelling, and pain are noticeable signs of inflammation. Inflammation is the immune system's response to infection and injury.
The body receives pain signals from nerve receptors when inflammation occurs. These signals result from complex responses and interactions between cells and chemicals in the body.
Anti-inflammatory drugs reduce pain partly by reducing inflammation. People can use these drugs to relieve symptoms of pain, stiffness, swelling, and fever.
The painkilling action of NSAIDs reduces the direct effect of inflammation on pain-nerve stimulation and sensitivity, but also the indirect effect of inflammatory heat and swelling.
How do NSAIDs work?
NSAIDs are a broad group of drugs from a number of different classes. While they all act in a similar way, NSAIDs do not have similar chemical structures. Their classification as painkillers lies in them all having a nonsteroidal effect against inflammation, and the following three clinical effects in common:
- They reduce high temperature and fever
- They reduce inflammation
- They reduce pain
NSAIDs work by hindering the formation of compounds known as prostaglandins. Prostaglandins play an important role in the body's inflammatory response.
These compounds produce chemical signals that calling up the immune system's inflammatory responses. Reducing the amount of prostaglandins that are produced by tissue damage, in turn, reduces inflammation.
NSAIDs block an enzyme called cyclooxygenase, also known as COX or Cox. The COX enzyme helps the reactions that produce prostaglandins.
Blocking COX also inhibits the function of platelets, cells in the blood that clot to help prevent bleeding. This function gives NSAIDs their anticlotting property.
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What do NSAIDs treat?
NSAIDs are used for a broad variety of reasons, including the following problems involving short- or long-term pain:
Headache is one pain for which NSAIDs are an option.
- Backache - particularly long-term pain in the lower back
- Cold or flu
- Period pains
- Joint or bone injuries, sprains, and strains
- Muscle or joint complaints
NSAIDs may be used for three broad symptom areas associated with a long list of potential conditions:
- High temperature or fever
While aspirin can be considered a different kind of drug when it is used at low doses, it can also be used to prevent certain conditions. Aspirin is used against the artery disease that can lead to heart attack or stroke. It may also be used to reduce the risk of some types of colorectal cancer.
Headache and lower back pain are two of the more common reasons for using NSAIDs. If these problems become long-term issues, patients should consider the safety of using NSAIDs.
Using NSAIDs for cold and flu
It has been widespread practice for over a hundred years to take NSAIDs for pain and fever brought on by the common cold.
However, these drugs do not kill the virus or improve the course of the illness. NSAIDs simply relieve some of the symptoms, including fever.
A systematic review of the best available evidence for treating a common cold with NSAIDs shows that they produce significant results against headache, ear pain, and muscle and joint pain.
Precautions for using NSAIDs
How the body responds to NSAIDs varies from person to person, and some people will experience side effects. High doses and long-term use also make some side effects more likely.
NSAIDs also interact with some other drugs, and people with certain conditions should not use them. Alcohol does not have an interaction with these particular painkillers, although drinking excessive amounts while using NSAIDs can irritate the gut.
Patients should always read the label before taking painkillers.
People using other medications should let their pharmacist or doctor know. Taking more than one kind of NSAID can also have adverse effects.
Patients should always follow the label for the particular NSAID they are using as NSAIDs form a broad group of different drugs that can have different effects.
A precaution that applies to all NSAIDS is not to take them while also taking anticlotting drugs - for example, while using aspirin (itself also an NSAID), or warfarin.
Children under 16 years of age and people over 65 may need to avoid taking NSAIDS. Other people who should avoid these drugs or take them with medical guidance include people with:
- An allergy to NSAIDs
- Asthma (this can be worsened by the drugs in a proportion of cases)
- Pregnancy or breastfeeding
- Heart disease
Side effects of NSAIDs and long-term safety
Aside from the precautions mentioned above, taking NSAIDs can have side effects.
Serious side effects are less common than mild ones, and the likelihood of any side effect varies between people. Anyone is more likely to suffer problems if the drugs are used in high doses or over a long term.
Drugs taken on prescription generally have a greater risk as well as a greater painkilling power than NSAIDs that are available over the counter.
The less severe side effects experienced by some people include indigestion and other gut complaints, headaches, dizziness, and drowsiness.
Adverse events rarely associated with NSAIDs include problems with fluid retention, the kidneys, liver, or the heart and circulation.
Rarely, the risk of heart attack and stroke is slightly increased by taking NSAIDs, although taking low-dose aspirin is not included in this risk.
Peptic ulcers and gastrointestinal bleeding
Long-term or high-dose use of NSAIDs could also lead to ulcers developing in the gut known as peptic ulcers. Peptic ulcers form because the action of NSAIDs blocking the COX enzyme has an undesirable effect in addition to the main beneficial one.
Long-term NSAID use can leave the stomach vulnerable to damage caused by digestive acid.
Blocking COX is beneficial for inhibiting the production of prostaglandins as they mediate inflammation. However, prostaglandins also act as protectors of the stomach lining by helping the stomach walls produce mucous that defends them from stomach acid.
NSAIDs are readily available without prescription and used widely. This means that the risk of NSAIDs causing peptic ulcers is as important as the other major cause of these lesions in the stomach or small intestine, the bacteria Helicobacter pylori.
One potential complication of ulcers is that they can start to bleed. NSAID drugs have an anticlotting effect that can promote bleeding.
People who take NSAIDs for a long time, at high doses, or both should consult their doctor about ulcer prevention. One option is to take separate drugs that reduce acid production in the stomach. Using a different type of painkiller is another option.
People at risk of getting peptic ulcer disease could use a non-NSAID painkiller - acetaminophen is one preference. This is listed by the American College of Gastroenterology in its consumer health guide because acetaminophen is not associated with the risk of ulcers in the stomach or small intestine.
Acetaminophen is not always suitable, however, and presents its own risks, including potential liver problems, especially if taken with alcohol.