Indomethacin is a non-steroidal anti-inflammatory drug (NSAID) used to treat acute painful attacks of gouty arthritis. It is one of the original NSAID’s in its class gaining U.S. Food and Drug Administration (FDA) approval in 1965. In gout it is used to treat an acute episode of gouty arthritis, it is not useful or indicated as a preventative.
Indocin is a common brand name for indomethacin. Drugs like Indocin have been used to treat various inflammatory conditions for over 100 years. It has only been the last 20-30 years that medical research has understood the mechanisms by with these drugs work. Ongoing study reveals additional information and insights into the action of NSAID’s and the inflammatory response. As science identifies the complex role inflammation plays in many conditions, the role of indomethacin expands. To understand how Indocin treats gout, understanding the inflammatory response is necessary.
Inflammation occurs when the human body detects a substance it considers “foreign.” Each individual has cellular markers, protein sites on the walls of each cell, that identify that cell as “self.” When circulating white blood cells of a certain type identify a substance without these identifying markings it sets up a series of events called innate immunity. This is the “first responder” to a foreign protein like the venom from a bee sting, a bacteria, or even blood. When red blood cells are inside blood vessels, the body identifies them as belonging. When blood escapes the blood vessel into tissue from injury, it is no longer viewed as normal and innate immunity stimulates an inflammatory reaction.
Ancient healers identified the characteristics of inflammation long ago and the attributes still remain.
Think about a bee sting. The area almost immediately becomes red, swollen, painful and hot. This is a local inflammatory reaction or innate immunity.
Prostaglandins are chemical mediators in the body that serve several important functions. A major role of prostaglandins is in the inflammatory reaction. Recent study suggests that prostaglandins not only have a vital role in starting and organizing the inflammatory response, but also is responsible for turning off the body’s reaction to inflammation.
Prostaglandins are made in every cell in the body. Specifically in inflammation, they are released in response to cell injury and are responsible for initiating the inflammatory response. In general, they call out to other immune cells already in circulation by chemical messaging (chemotaxis) and direct them to the site of the injury. They also stimulate the body to start production of the many types of white blood cells required to respond to the cellular damage. Prostaglandins can be thought of as the “first responders” to injury or invasion (bacterial and viral infection for example.)
One of the direct local effects of prostaglandins includes vasodilation, meaning enlargement of the blood vessels, which increases circulation to the area. When the blood vessels are bigger, more blood can be delivered. This carries more white blood cells and proteins to heal the inflammation. Another function is the stimulation of pain mediators. This helps keep the area of inflammation at rest. These account for the classic findings of inflammation (redness, swelling, pain and heat.)
Cyclooxygenase (COX) is the enzyme that converts a substance called arachidonic acid into prostaglandin. This occurs within each cell, not in the blood stream. Two Cox enzymes have been isolated and their respective functions identified.
Many NSAID’s, particularly the older one’s including indomethacin, are non-selective COX inhibitors. This means that the effects of the drug decrease the action of both Cox 1 and Cox 2. Less COX means less prostaglandin. Less prostaglandin means less inflammation. In recent years selective COX 2 inhibitor NSAID’s have been developed, which only target the COX 2 enzymes. The difference can be important in patients with other medical conditions such as peptic ulcer disease, clotting abnormalities or heart disease.
A partial list of NSAID’s by Cox inhibition includes:
The unwanted side effects from the use of NSAID’s when used for gout are from the unintentional COX 1 inhibition as well as the general effects on kidney function from all NSAID’s.
Gastrointestinal irritation, which may range from stomach upset to active bleeding, is not uncommon. People with a history of ulcer disease should avoid non-selective COX inhibitor NSAID’s.
Bleeding disorders, including patients on blood thinners, should avoid NSAID’s as prostaglandins have a vital role in blood clotting.
Folks with Raynaud’s disease, Prinzmetal’s angina and men with erectile dysfunction may experience worsening of symptoms as prostaglandins are vaso-dilators. Blocking that action can increase constriction of blood vessels and worsen symptoms.
Cardiovascular risks have been identified in people who have had a previous heart attack. Issues with blocking the protective effects of daily aspirin as well as a link to congestive heart failure have been suggested.
Regulating blood flow through the kidneys is a prime function of prostaglandins. Blocking prostaglandin renal function can be a significant and life threatening side effect. Both Cox 1 and Cox 2 act as vasodilators in the kidneys. When kidney function becomes compromised for any reason (dehydration, atherosclerotic disease, other drug side effects, diabetes), prostaglandins dilate the vessels in the kidney to compensate for the decrease in renal blood flow. NSAID’s block this compensatory mechanism, and can accelerate the rate of renal failure. In general COX 1 and COX 2 have different organ targets, however both have an effect on the kidney. No one with renal failure, even mild, should consider taking NSAID’s.
A special note here about aspirin use as an anti-inflammatory in gout. Because of the structural chemistry of the acetylsalicylic acid, aspirin use can actually cause a gout attack. This appears to reverse at very high doses but in general, aspirin is not a good choice in the treatment of a gouty attack.
Indomethacin and NSAID’s may be preferable to other drug therapies to treat an acute painful attack of gout; however; they are not without risks and side effects. Using these drugs at the time to relieve a flare will be a God-send, but you would be smart to consider what can be done to prevent having to use them again in the future. Are you doing everything that can be done that is not potentially harmful? Research every non-drug approach to lowering uric acid before resolving to use NSAID’s in the future. There are many ways to accomplish this without the use of potentially dangerous pharmaceuticals.
Prostaglandins and Inflammation
The Role of Prostaglandins in Inflammation
Prostaglandins and Inflammation
Comparative Inhibitory Activity of Rofecoxib, Meloxicam, Diclofenac, Ibuprofen, and Naproxen on COX-2versus COX-1 in Healthy Volunteers.
Low Dose Aspirin Intake Increases Risk of Recurrent Gout Attacks: The Online Case-Crossover Gout Study
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