Are Allopurinol Side Effects Serious?

Do allopurinol side effects worry you?

Allopurinol is a powerful drug, so perhaps it is not surprising that many people worry.

Stop worrying and learn how this medication really helps gout, as long as you use it correctly.

I list the standard allopurinol side effects below, but before you look at these, you need to know about one side effect that is rarely explained properly.

This is not a side effect of allopurinol as such, as it applies to all uric acid lowering therapies. When you lower uric acid properly, to a level that gets rid of old uric acid crystals, the melting uric acid crystals can trigger a gout flare. This is a necessary, though sometimes painful consequence of proper treatment.

Don’t avoid allopurinol just because it might trigger a painful flare. This is one side effect that you should welcome, as it indicates that you are getting better. This effect will diminish, as long as you continue taking allopurinol daily and get your uric acid level checked frequently.

As I’ve said many times in the gout forums:

If you take allopurinol you might get a gout flare. If you do nothing, you will get a gout flare.

See below for More Allopurinol Information including more on the most common, but least discussed of allopurinol side effects: pain.

Allopurinol Side Effects

Note that the side effects listed below are not experienced by everyone. Some are common, others rare, some people have no side-effects, or are happy to accept a little discomfort in exchange for the permanent relief from acute gout attacks. As with all treatments, you must decide what is best for you in your particular circumstances and you must discuss side-effects fully with your doctor before you start to take any drug and whenever you experience any adverse effects.

The following list may not be complete – if you experience any other problem that you think may be related to taking the drug, then you must consult your doctor.

Minor side effects that may go away
You only need consult your doctor if these become severe
  • Indigestion
  • Drowsiness
  • Headache
  • Stomach pain
  • Unusual hair loss
  • Diarrhea
  • Nausea, unless with skin rash – this is serious – see below

Serious side effects
The most serious side effect is known as allopurinol hypersensitivity syndrome which effects 1 in 1000 patients. The risk of this increases with age. You must stop taking the drug and consult your doctor if you have any of the following
  • Aching or painful muscles
  • Blood in stools
  • Blood in urine
  • Breathing troubled or short
  • Bruising or bleeding without obvious cause
  • Chest tight or wheezing
  • Chills
  • Eyes irritated or red or yellow
  • Fever
  • Fingernails loose
  • Glands swollen or painful
  • Hands or feet numb, tingling, painful or weak
  • Hives
  • Itching
  • Lethargy (tiredness or weakness without obvious cause)
  • Lower back or side pain
  • Mouth or lips sore, ulcerated or showing white spots
  • Painful or difficult urination
  • Rapid weight gain
  • Rash, especially with vomtting or nausea
  • Red pinpoint skin spots
  • Skin red, tender, burning or peeling
  • Skin sores
  • Skin thickened or scaly
  • Skin yellow
  • Sore, bleeding lips
  • Swelling of face, feet, fingers, lower legs or stomach
  • Tarry, black stools
  • Throat sore and feverish
  • Urine suddenly decreases in amount

More Allopurinol Information

Read more vital allopurinol information:

Minimize Allopurinol Side Effects
To minimize allopurinol side effects the best approach is to start low. Some people should avoid allopurinol altogether. Get risk reduction advice now.
Are Allopurinol Side Effects Serious?
Allopurinol side effects worry many people, so just how serious are they?
3 Vital Allopurinol Dosage Rules
Allopurinol dosage needs to be planned, measured and adjusted for different treatment phases. A standard 300mg dose might be just what you need – but make sure that it is set by diagnosis and judgment, not by dangerous guesswork.
Allopurinol For Gout Control
In-depth look at the management of gout using allopurinol.
Allopurinol Drug Not Just For Gout
Though mostly used in gouty arthritis, the allopurinol drug has found to be useful for other conditions.
Is this Allopurinol For Gout right for me?

Allopurinol Misspellings

Like many medicines, allopurinol is often misspelled. Though spelling is often overrated, it pays to take extra care with medicines, as a misunderstanding might cause treatment problems in the unlikely event of a similar sounding drug being taken mistakenly.


allo changed to ali, and nol changed to nal.


allo changed to ali.


allo changed to alli, and nol changed to nal.


nal ending changed to nol. This is the most frequent mis-spelling of allopurinol


Missing final l.


This is the correct spelling of allopurinol – the most common gout treatment for lowering uric acid.


purinol changed to purionol [extra o added before nol].


lupo changed to lopu.


lop changed to lup.


allo changed to alo, and purin changed to puren.


allo changed to alo, and nol changed to nal.


allo changed to alo.


allo changed to alu, and puri changed to pro.


Allo changed to Alu, and extra o added before nol.


allo changed to ap.


Purinol is a brand of allopurinol manufactured by Europharm

If you are aware of other alternative spellings, or if you have any questions or opinions about allopurinol side effects, please discuss them in the gout forum.

See more in the allopurinol side effects guidelines.

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Medical Disclaimer: The pupose of GoutPal is to provide jargon-free explanations of medical gout-related terms and procedures. Because gout sufferers need to know what questions to ask their doctor. Also, you need to understand what your doctor tells you. So this website explains gout science. But it is definitely NOT a substitute for medical advice.

Information on this website is provided by a fellow gout sufferer (Keith Taylor) with an accountant's precision for accurate data. But no medical qualifications. So you must seek professional medical advice about gout and any other health matters.

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