Nonsteroidal anti-inflammatory drugs ( NSAID) are members of a therapeutic drug class which Analgesic, decreases inflammation, Antipyretic, and Antithrombotic. Side effects depend on the specific drug, its dose and duration of use, but largely include an increased risk of Stomach ulcers, heart attack, and kidney disease. Well-known nonsteroidal anti-inflammatory drugs include aspirin, ibuprofen, diclofenac, and naproxen, all of which are available over the counter (OTC). Paracetamol (acetaminophen) is generally not considered an NSAID because it has only minor anti-inflammatory activity.
The term nonsteroidal, common from around 1960, distinguishes these drugs from corticosteroids, another class of anti-inflammatory drugs, which during the 1950s had acquired a bad reputation due to overuse and side-effect problems after their introduction in 1948.
Nonsteroidal anti-inflammatory drugs work by inhibiting the activity of cyclooxygenase (the COX-1 and COX-2 isozyme). In cells, these enzymes are involved in the synthesis of key biological mediators, namely , which are involved in inflammation, and , which are involved in Coagulation.
There are two general types of NSAIDs available: non-selective and COX-2 selective. Most NSAIDs are non-selective, and inhibit the activity of both COX-1 and COX-2. These NSAIDs, while reducing inflammation, also inhibit platelet aggregation and increase the risk of gastrointestinal ulcers and bleeds. COX-2 selective inhibitors have fewer gastrointestinal side effects, but promote thrombosis, and some of these agents substantially increase the risk of heart attack. As a result, certain COX-2 selective inhibitors—such as rofecoxib—are no longer used due to the high risk of undiagnosed vascular disease. These differential effects are due to the different roles and tissue localisations of each COX isoenzyme. By inhibiting physiological COX activity, NSAIDs may cause deleterious effects on kidney function, and, perhaps as a result of water and sodium retention and decreases in renal blood flow, may lead to heart problems.
An estimated 10–20% of people taking NSAIDs experience indigestion. In the 1990s, high doses of prescription NSAIDs were associated with serious upper gastrointestinal adverse events, including bleeding.
There is an argument over the benefits and risks of NSAIDs for treating chronic musculoskeletal pain. Each drug has a benefit-risk profile, and balancing the risk of no treatment with the competing potential risks of various therapies should be considered. For people over the age of 65 years old, the balance between the benefits of pain-relief medications such as NSAIDs and the potential for adverse effects has not been well determined.
Side effects are dose-dependent, and in many cases, severe enough to pose the risk of ulcer perforation, upper gastrointestinal bleeding, and death, limiting the use of NSAID therapy. An estimated 10–20% of NSAID patients experience dyspepsia, and NSAID-associated upper gastrointestinal adverse events are estimated to result in 103,000 hospitalizations and 16,500 deaths per year in the United States, and represent 43% of drug-related emergency visits. Many of these events are avoidable; a review of physician visits and prescriptions estimated that unnecessary prescriptions for NSAIDs were written in 42% of visits.
Aspirin should not be taken by people who have salicylate intolerance or a more generalized drug intolerance to NSAIDs, and caution should be exercised in those with asthma or NSAID-precipitated bronchospasm. Owing to its effect on the stomach lining, manufacturers recommend people with , mild diabetes, or gastritis seek medical advice before using aspirin. Use of aspirin during dengue fever is not recommended owing to increased bleeding tendency. People with kidney disease, hyperuricemia, or gout should not take aspirin because it inhibits the ability of the kidneys to excrete uric acid, and thus may exacerbate these conditions.
Rofecoxib (Vioxx) was shown to produce significantly fewer gastrointestinal adverse drug reactions (ADRs) compared with naproxen. The study, the VIGOR trial, raised the issue of the cardiovascular safety of the coxibs (COX-2 inhibitors). A statistically significant increase in the incidence of myocardial infarctions was observed in patients on rofecoxib. Further data, from the APPROVe trial, showed a statistically significant relative risk of cardiovascular events of 1.97 versus placebo—which caused a worldwide withdrawal of rofecoxib in October 2004.
NSAIDs, aside from (low-dose) aspirin, are associated with a doubled risk of heart failure in people without a history of cardiac disease. In people with such a history, use of NSAIDs (aside from low-dose aspirin) was associated with a more than 10-fold increase in heart failure. If this link is proven causal, researchers estimate that NSAIDs would be responsible for up to 20 percent of hospital admissions for congestive heart failure. In people with heart failure, NSAIDs increase mortality risk (hazard ratio) by approximately 1.2–1.3 for naproxen and ibuprofen, 1.7 for rofecoxib and celecoxib, and 2.1 for diclofenac.
In July 2015, the US Food and Drug Administration (FDA) toughened warnings of increased heart attack and stroke risk associated with nonsteroidal anti-inflammatory drugs (NSAIDs) other than aspirin.
According to a study published in 2011, men who use NSAIDs regularly are at significantly increased risk of erectile dysfunction. The study was observational and not controlled, with a low original participation rate, potential participation bias, and other uncontrolled factors. The authors warned against drawing any conclusions regarding cause.
Common gastrointestinal side effects include:
Clinical NSAID ulcers are related to the systemic effects of NSAID administration. Such damage occurs irrespective of the route of administration of the NSAID (e.g., oral, rectal, or parenteral) and can occur even in people who have achlorhydria.Textbook of Gastroenterology, Tadataka Yamada, 2008, Ch.40, Peptic Ulcer Disease, page 941
Ulceration risk increases with therapy duration and with higher doses. To minimize GI side effects, it is prudent to use the lowest effective dose for the shortest period—a practice that studies show is often not followed. Over 50% of patients on long term NSAID treatments of 6 or more months, sustained some mucosal damage to their small intestine.
The risk and rate of gastric adverse effects are different depending on the type of NSAID medication a person is taking. Indomethacin, ketoprofen, and piroxicam use appears to lead to the highest rate of gastric adverse effects, while ibuprofen (lower doses) and diclofenac appear to have lower rates.
Certain NSAIDs, such as aspirin, have been sold in enteric coating formulations that manufacturers claim reduce the incidence of gastrointestinal ADRs. Similarly, some believe that rectal formulations may reduce gastrointestinal ADRs. However, consistent with the systemic mechanism of such ADRs, and in clinical practice, these formulations have not demonstrated a reduced risk of GI ulceration.
Numerous "gastro-protective" drugs have been developed to prevent gastrointestinal toxicity in people who need to take NSAIDs regularly. Gastric adverse effects may be reduced by taking medications that suppress acid production such as proton pump inhibitors (e.g.: omeprazole and esomeprazole), or by treatment with a drug that mimics prostaglandin to restore the lining of the GI tract (e.g.: a prostaglandin analog misoprostol). Diarrhea is a common side effect of misoprostol; however, higher doses of misoprostol have been shown to reduce the risk of a person having a complication related to a gastric ulcer while taking NSAIDs. While these techniques may be effective, they are expensive for maintenance therapy.
Hydrogen sulfide NSAID hybrids have been studied as a way of trying to reduce the gastric ulceration/bleeding side effects of NSAIDs. This is motivated by the fact that hydrogen sulfide is known to impact the gastrointestinal system, with either a pro-inflammatory or anti-inflammatory effect depending on the dose. Early results in rats and rabbits have been promising.
Common ADRs associated with altered kidney function include:
These agents may also cause kidney impairment, especially in combination with other nephrotoxic agents. Kidney failure is especially a risk if the patient is also concomitantly taking an ACE inhibitor (which removes angiotensin II's vasoconstriction of the efferent arteriole) and a diuretic (which drops plasma volume, and thereby RPF)—the so-called "triple whammy" effect.
Nonsteroidal anti-inflammatory drugs in combination with excessive use of phenacetin or paracetamol (acetaminophen) may lead to analgesic nephropathy.
Benoxaprofen, since withdrawn due to its hepatotoxicity, was the most photoactive NSAID observed. The mechanism of photosensitivity, responsible for the high photoactivity of the 2-arylpropionic acids, is the ready decarboxylation of the carboxylic acid functional group. The specific absorbance characteristics of the different chromophore 2-aryl substituents, affects the decarboxylation mechanism.
In contrast, paracetamol (acetaminophen) is regarded as being safe and well tolerated during pregnancy, but a study released in 2010, indicated that there may be associated male infertility in the unborn. Doses should be taken as prescribed, due to risk of liver toxicity with overdoses.
In France, the country's health agency contraindicates the use of NSAIDs, including aspirin, after the sixth month of pregnancy.
In October 2020, the US Food and Drug Administration (FDA) required the prescribing information to be updated for all nonsteroidal anti-inflammatory medications, to describe the risk of kidney problems in unborn babies which can then lead to low amniotic fluid levels, as a result of the use of NSAIDs. The FDA recommends avoiding the use of NSAIDs by pregnant women at 20 weeks or later in pregnancy.
There is moderate evidence that they delay bone healing. Their overall effect on soft-tissue healing is unclear.
Common adverse drug reactions (ADR), other than those listed above, include: raised liver enzymes, headache, dizziness. Uncommon ADRs include an hyperkalaemia, confusion, bronchospasm, and rash. Ibuprofen may also rarely cause irritable bowel syndrome symptoms. NSAIDs are also implicated in some cases of Stevens–Johnson syndrome.
Most NSAIDs penetrate poorly into the central nervous system (CNS). However, the COX enzymes are expressed constitutively in some areas of the CNS, meaning that even limited penetration may cause adverse effects such as somnolence and dizziness.
Nonsteroidal anti-inflammatory drugs may increase the risk of bleeding in patients with Dengue fever For this reason, NSAIDs are only available with a prescription in India.
In very rare cases, ibuprofen can cause aseptic meningitis.
allergy to NSAIDs might exist. While many allergies are specific to one NSAID, up to 1 in 5 people may have unpredictable cross-reactive allergic responses to other NSAIDs.
Nonsteroidal anti-inflammatory drugs cause decreased ability to form blood clots, which can increase the risk of bleeding when combined with other drugs that also decrease blood clotting, such as warfarin.
Nonsteroidal anti-inflammatory drugs may aggravate hypertension (high blood pressure) and thereby antagonize the effect of antihypertensives, such as .
Nonsteroidal anti-inflammatory drugs may interfere and reduce effectiveness of SSRI antidepressants through inhibiting TNFα and IFNγ, both of which are cytokine derivatives. NSAIDs, when used in combination with SSRIs, increase the risk of adverse gastrointestinal effects. NSAIDs, when used in combination with SSRIs, increase the risk of internal bleeding and brain hemorrhages.
Various widely used NSAIDs enhance endocannabinoid signaling by blocking the anandamide-degrading membrane enzyme fatty acid amide hydrolase (FAAH).
Nonsteroidal anti-inflammatory drugs may reduce the effectiveness of . An In vitro study on cultured bacteria found that adding NSAIDs to antibiotics reduced their effectiveness by around 20%.
The concomitant use of NSAIDs with alcohol and/or tobacco products significantly increases the already elevated risk of during NSAID therapy.
COX-1 is a constitutively expressed enzyme with a "house-keeping" role in regulating many normal physiological processes. One of these is in the stomach lining, where prostaglandins serve a protective role, preventing the stomach mucosa from being eroded by its own acid. COX-2 is an enzyme facultatively expressed in inflammation, and it is inhibition of COX-2 that produces the desirable effects of NSAIDs.
When nonselective COX-1/COX-2 inhibitors (such as aspirin, ibuprofen, and naproxen) lower stomach prostaglandin levels, ulcers of the stomach or duodenum and internal bleeding can result. The discovery of COX-2 led to research to the development of selective COX-2 inhibiting drugs that do not cause gastric problems characteristic of older NSAIDs.
Nonsteroidal anti-inflammatory drugs have been studied in various assays to understand how they affect each of these enzymes. While the assays reveal differences, unfortunately, different assays provide differing ratios.
Paracetamol (acetaminophen) is not considered an NSAID because it has little anti-inflammatory activity. It treats pain mainly by blocking COX-2, mostly in the central nervous system, but not much in the rest of the body.
However, many aspects of the mechanism of action of NSAIDs remain unexplained, and for this reason, further COX pathways are hypothesized. The COX-3 pathway was believed to fill some of this gap, but recent findings make it appear unlikely that it plays any significant role in humans, and alternative explanation models are proposed.
Nonsteroidal anti-inflammatory drugs interact with the endocannabinoid system and its , as COX-2 have been shown to utilize endocannabinoids as substrates, and may have a key role in both the therapeutic effects and of NSAIDs, as well as in NSAID-induced placebo responses.
Nonsteroidal anti-inflammatory drugs are also used in the acute pain caused by gout because they inhibit urate crystal phagocytosis besides inhibition of prostaglandin synthase.
Ibuprofen and ketoprofen are available in single-enantiomer preparations (dexibuprofen and dexketoprofen), which purport to offer quicker onset and an improved side-effect profile. Naproxen has been sold as the single active enantiomer.
Regarding adverse effects, selective COX-2 inhibitors have a lower risk of gastrointestinal bleeding. Except for naproxen, nonselective NSAIDs increase the risk of having a heart attack. Some data also supports that the partially selective nabumetone is less likely to cause gastrointestinal events.
Consumers Union found that ibuprofen, naproxen, and salsalate are less expensive than other NSAIDs, and essentially as effective and safe when used appropriately to treat osteoarthritis and pain. Treating Osteoarthritis and Pain: The Non-Steroidal Anti-Inflammatory Drugs Comparing Effectiveness, Safety, and Price
Consumers Union 2005
Nonsteroidal anti-inflammatory drugs can also be divided into short-acting (plasma half-life less than 6 h) such as aspirin, diclofenac, and ibuprofen; and long-acting (half-life approximately greater than 10 h) such as naproxen and celecoxib.
Willow bark (from trees of the Willow genus) was widely known to be used as a medicine by multiple First Nations communities.
In the body, salicin is turned into salicylic acid, which produces the antipyretic and analgesic effects that the plants are known for.
Salicin was first isolated by Johann Andreas Buchner in 1827. By 1829, French chemist Henri Leroux had improved the extraction process to obtain about 30g of purified salicin from 1.5kg of willow bark.
By 1897, the German chemist Felix Hoffmann and the Bayer company prompted a new age of pharmacology by converting salicylic acid into acetylsalicylic acid—named aspirin by Heinrich Dreser. Other NSAIDs like ibuprofen were developed from the 1950s forward. In 2001, NSAIDs accounted for 70,000,000 prescriptions and 30billion over-the-counter doses sold annually in the United States.
In the United States, meloxicam is approved for use only in canines, whereas (due to concerns about kidney damage) it carries warnings against its use in cats except for one-time use during surgery. Metacam 5 mg/mL Solution for Injection, Supplemental Approval 28 October 2004. In spite of these warnings, meloxicam is frequently prescribed "off-label" for non-canine animals including cats and livestock species. In other countries, for example the European Union (EU), there is a label claim for use in cats.
Possible erectile dysfunction risk
Gastrointestinal
Renal
Photosensitivity
During pregnancy
Allergy and allergy-like hypersensitivity reactions
Possible effects on bone and soft tissue healing
Ototoxicity
Other
Interactions
Mechanism of action
Antipyretic activity
Classification
Salicylates
Propionic acid derivatives
Acetic acid derivatives
Enolic acid (oxicam) derivatives
Anthranilic acid derivatives (Fenamates)
Selective COX-2 inhibitors (Coxibs)
Sulfonanilides
Others
Chirality
Main practical differences
Pharmacokinetics
History
Veterinary use
See also
External links
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