Prevention of recurrent attacks of gout
What can I do?
As already mentioned, there may be obvious reasons why gout attacks continue to recur, such as:
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Medications
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Obesity (overweight)
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Excess alcohol consumption.
These factors may well be modifiable and should be discussed with the doctor.
Dietary advice for gout sufferers
Many people are keen to address their diet to reduce their risk of recurrent attacks. In practice, most dietary modifications have only a small effect on uric acid levels in the blood and hence only a small effect on the risk of recurrent attacks of gout.
In general, foods rich in chemicals called purines (found particularly in protein-rich foods), which are broken down in the body to uric acid, tend to raise the urate level in the blood.
A diet low enough in purine to reduce the blood uric acid level by only 10-15% is very difficult to stick to and some might argue that the diet is so unpalatable that they would rather suffer gout! Adequate treatment of recurrent gout, on the other hand, often requires the uric acid level to be consistently lowered by 50%; this is very difficult to achieve and maintain long term through dietary modification.
To complicate matters further, the effects of dietary modification are sometimes unpredictable; for example, yoghurt is high in protein, but a yoghurt-rich diet tends to lower uric acid levels, although again only by modest amounts.
It is of course possible to measure the effect of dietary modifications by checking the blood level of uric acid before and after a dietary modification, but it is important to remember that single measurements can be misleading, and the modification would need to be sustained long-term.
To be sceptical about the effects of diet is not to deny that certain foods which affect the urate level sharply might not precipitate acute attacks; people will often discover these precipitants for themselves, but common culprits are:
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Sardines
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Offal (edible internal parts of an animal eg liver)
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Shellfish
Further dietary information is available from the UK Gout Society (www.ukgoutsociety.org).
In practice, most patients with recurrent gout and high uric acid levels need medication to successfully reduce the uric acid level enough to prevent attacks.
Medication to prevent recurrent attacks of gout
Drugs are available which reduce over-production of uric acid, as well as ones which enhance excretion through the kidney (called uricosuric drugs). In theory therefore, which drug is used can be tailored to the cause, whether over-production or under excretion. In practice, in many cases the cause is a bit of both, and the drug used to treat over-production (allopurinol, Zyloric®) is much more effective and better tolerated than uricosuric drugs, and so is usually first choice. It is worth noting that if significant kidney function impairment is present, uricosuric drugs cannot further increase the amount of uric acid excreted in the urine.
Allopurinol
Allopurinol works by inhibiting the action of the chemical xanthine oxidase (see above) so the production of uric acid falls. The higher the dose (usually been 100 mg and 300 mg daily, but up to 900 mg daily) the more the uric acid level in the blood falls. The drug is most conveniently taken all at once first thing in the morning.
Allopurinol has been around for a long time with a very good and safe track record. Side-effects are rare; a small number of patients have an allergic reaction, usually consisting of a fever and itchy rash, which settles when the drug is discontinued.
If this happens it can be possible to introduce the drug at very small doses (as a liquid, which usually needs to be made up in hospital), gradually increasing the dose so the patient becomes tolerant, much as is sometimes done with pollen for hay fever.
This allergic reaction is often confused with, but must be distinguished from, another more common problem with allopurinol; we have already discussed that sudden changes in the uric acid level in the blood can precipitate gout attacks. Therefore, when allopurinol is introduced, there can be a paradoxical initial increase in the frequency and intensity of attacks. This is not an allergic reaction and does not mean that the patient cannot take allopurinol.
To avoid this problem, first of all, allopurinol should not be started until a couple of weeks after an attack of gout has settled.
Secondly, either the anti-inflammatory medication used to treat the attack should be continued for the first few weeks of treatment, or the anti-inflammatory should be kept to hand to be started at the first hint of an attack. Should an attack happen, the allopurinol should be continued.
Allopurinol is not a magic cure; it took many years for uric acid to build up in the joint lining, and the deposits will only gradually disappear once the blood level has been brought down. It may take at least a year of adequate allopurinol treatment for the attacks of gout to cease, and for any tophi to noticeably decrease in size. In the meantime any attacks can be treated in the normal way.
It would be usual to check the uric acid level after about 6 weeks of treatment with allopurinol. This is to ensure that it is effectively lowering the uric acid level (and that the patient is taking the drug).
While lowering the uric acid level into the normal range is usually associated with some improvement in gout, to effectively ensure elimination of gout attacks in the long term, most experts recommend aiming for a level of 330 micmol/l or less, and this may require gradually increasing the allopurinol dose until this target is reached. The normal range varies between laboratories but in men a typical normal range is between 210 and 450 micmol/l, and in women 170 and 370.
How long do I need to continue allopurinol?
Although some studies suggest that allopurinol can be discontinued after 7 years with only a low rate of relapse, most experts recommend continuing indefinitely. This makes sense, as one would anticipate that stopping the drug would result in a rise of uric acid level in the blood, accumulation in the joint lining and eventual recurrence. There is no evidence to suggest that allopurinol is associated with any harmful effects if taken long term.
What if I cannot take allopurinol?
This is perhaps the biggest unsolved problem in the treatment of gout. As suggested above, uricosuric drugs may be helpful. Because allopurinol is so successful, many of these are now difficult to get hold of. One of the oldest drugs is probenicid, which can no longer be routinely prescribed in the UK. A drug called sulfinpyrazone is available, but requires regular blood tests to monitor for side effects, as does a drug called benzbromarone, which also requires special prescribing arrangements. A routinely available blood pressure tablet, losartan, has a small effect on increasing excretion of uric acid.
Finally, another effective xanthine oxidase inhibitor, Febuxostat, has recently become available in the UK. It has been approved by the National Institute for Health and Clinical Excellence for use in those who cannot take allopurinol, with the hope that it will solve the problem of gout for the small number of patients for whom the above treatments are unhelpful.
Unfortunately, at present, a small number of patients continue to suffer gout, with its complications such as tophi or kidney impairment. These patients remain either untreated or are treated with continuous anti-inflammatory medication. This is unsatisfactory as these treatments are often associated with side-effects when taken long-term, and the treatments do not improve the extra-articular manifestations.