Medical Author: William C. Shiel
Jr., MD, FACP, FACR
Medical Editor: Melissa Conrad Stöppler, MD
Many patients will read that aspirin increases the level of uric acid in the blood and that the blood level of uric acid is important in gout. What is the relationship between the two factors? Additionally, many patients are prescribed a low dose of aspirin (75-81 mg daily) to prevent heart attacks or strokes. What should patients be told about aspirin and gout? Will it cause gout in them?
These questions bring up a number of important issues about gout.
First, gout is a medical condition that is characterized by abnormally elevated levels of uric acid in the blood, recurring attacks of joint inflammation (arthritis), deposits of hard lumps of uric acid in and around the joints, and decreased kidney function and kidney stones. While gout is often associated with an abnormally elevated blood uric acid level, it need not be. This means that the medical condition of gout can exist in an individual regardless of an elevated uric acid level in that person. This even holds true for an acute attack of gouty arthritis! Moreover, many patients with elevated blood levels of uric acid (hyperuricemia) never develop gout.
It is, therefore, important to understand that it may not necessarily be the level of uric acid that triggers an acute attack of gout. Frequently, acute attacks are precipitated by a rapid change in the level of uric acid, either up or down. Additionally, the tendency toward developing gout seems to be significantly influenced by the metabolism a person inherits.
Secondly, it is true that small doses of aspirin can increase the level of uric acid in the blood because it can impair the excretion of uric acid from the kidneys. However, this change is typically only noted when aspirin is taken in the usual over-the-counter doses (two 325 mg tablets every four hours). An extremely low dose of aspirin (75-81 mg per day), which is given, for example, for heart attack or stroke prevention, should not significantly alter the level of uric acid in the blood. Furthermore, even the higher doses mentioned should only cause an attack of gout in a person who already has the condition or is at risk for an attack, not in an individual with a normal metabolism.
Finally, it is interesting to note that aspirin has a very different effect on the blood level of uric acid when it is taken at very high doses, such as is prescribed by doctors for treating serious forms of inflammatory arthritis (like rheumatoid arthritis). In these very high doses, aspirin actually blocks the normal reabsorption of uric acid by a different part of the kidneys, thereby causing uric acid to be dumped out of the body in the urine and resulting in a lowering of the blood level of uric acid.
However, because of the effects of moderate and high-dose aspirin, which can alter the blood level of uric acid, aspirin and aspirin-containing products (see below) are generally avoided by people with known gout.
Common aspirin-containing products include Alka-Seltzer, Anacin, Arthritis Pain Formula, aspirin gum (Aspergum), Bayer, Bufferin, Darvon Compound, Doan's Pills, Ecotrin, Empirin, Excedrin, Fiorinal products, and Percodan products.