Allopurinol for gout
Examples
Allopurinol is taken in tablet form (oral). It is taken in
low dosages at first. The dosage is gradually increased to control uric acid
levels.
How It Works
Allopurinol prevents the release of a
substance called xanthine oxidase, which helps in the formation of uric acid.
In treatment for
gout
, allopurinol blocks the production of
uric acid
in the body.
Why It Is Used
Allopurinol may be prescribed to
prevent gout attacks. It also may be used because of:
- Overproduction of uric
acid.
- Frequent gout attacks.
- Presence of gritty,
chalklike clumps of uric acid crystals (
tophi
).
- Failure of other medicines to
adequately reduce uric acid levels.
- Allergy to uricosuric
medications, which increase the elimination of uric acid, or serious side
effects from these medicines. Uricosuric medications include probenecid
(Probalan) and sulfinpyrazone (Anturane).
- Poor kidney
function.
- History of uric acid kidney stones.
Allopurinol may also be used for the prevention of kidney
disease in people going through treatment for cancer.
The dose of
allopurinol may need to be lower for people who have chronic kidney disease or
are taking azathioprine.
Allopurinol is not recommended for people who:
- Have a known sensitivity to
allopurinol.
- Have a condition in which there is too much iron in
the body (
hemochromatosis
).
Allopurinol should not be started for the first time by
people who are still having symptoms caused by a gout attack.
How Well It Works
Allopurinol lowers the amount of
uric acid in the body.
1
After the proper dose is
reached, the uric acid levels should return to normal. Your doctor will monitor
your uric acid level within one month of starting or changing a dose of
allopurinol.
Treatment with allopurinol can reduce the size of
tophi
.
2
Side Effects
Skin rash is a common side effect.
Because a skin rash may be a symptom of an allergic reaction to allopurinol,
have your doctor evaluate any skin rash that develops while you are taking this
medicine.
Rare, serious side effects include:
- Inflammation of the liver (
hepatitis
).
- Failure of bone marrow to
produce blood cells (
aplastic anemia
).
- Inflammation of blood vessels (
vasculitis
).
- Allopurinol hypersensitivity
syndrome (a widespread rash, fever, mouth sores, poor kidney function, liver
inflammation, and other complications), which can be life-threatening.
Allopurinol interferes with many other medicines. It may
increase or decrease the levels of other medicines, which may increase the
toxicity of these medicines or reduce their effectiveness.
See
Drug Reference for a full list of side effects. (Drug Reference is not
available in all systems.)
What To Think About
- Allopurinol should not be used until the
symptoms of a gout attack are gone. But if you are already taking allopurinol,
continue to take it (even during an attack).
- Gout attacks may
increase at first for some people taking allopurinol. To avoid this, doctors
may prescribe either colchicine, which blocks the inflammation caused by uric
acid crystals, or low-dose nonsteroidal anti-inflammatory drugs (
NSAIDs
) to be taken at the same time. After normal
uric acid levels have been maintained for 6 to 12 months and no further attacks
occur, colchicine or NSAIDs do not need to be taken.
- Because of the
rare risk of serious side effects, many doctors may prefer uricosuric
medications to allopurinol.
- Laboratory studies, including a
complete blood count
(CBC) and liver and kidney
function studies, may be done after a few months of using allopurinol. Studies
may then be repeated every year in otherwise healthy people or more frequently
in people with other medical problems.
Complete the
new medication information form (PDF)
(What is a
PDF
document?)
to help you understand this medication.
References
Citations
-
Wortmann RL, Kelley WN (2005). Gout and hyperuricemia.
In ED Harris Jr et al., eds., Kelley's Textbook of Rheumatology, 7th ed., pp. 1402–1429. Philadelphia: Elsevier
Saunders.
-
Hellman DB, Stone JH (2005). Arthritis and
musculoskeletal disorders. In LM Tierney Jr et al., eds., Current Medical Diagnosis and Treatment, 44th ed., pp.
781–789. New York: McGraw-Hill.
Last Updated:July 11, 2008
Wortmann RL, Kelley WN (2005). Gout and hyperuricemia.
In ED Harris Jr et al., eds., Kelley's Textbook of Rheumatology, 7th ed., pp. 1402–1429. Philadelphia: Elsevier
Saunders.
Hellman DB, Stone JH (2005). Arthritis and
musculoskeletal disorders. In LM Tierney Jr et al., eds., Current Medical Diagnosis and Treatment, 44th ed., pp.
781–789. New York: McGraw-Hill.
