I’ve been taught that urate-lowering therapy is for patients who’ve had recurrent attacks of gout to the point of being troublesome (a specific guideline advised in this article is two or more attacks over 12 months), but apparently there’s also an argument for starting it after the first attack; at that point crystals are small and the joint hasn’t yet been damaged, and most patients are going to go on to experience recurrent attacks. So it’s worth discussing the pros and cons of each approach with the patient.
There is no benefit in starting urate-lowering therapy in hyperuricaemic patients who have not had gout.
I was also taught not to start allopurinol within some weeks of an attack; this article says the usual advice is 2 – 4 weeks. Interestingly, however, it cited one RCT of 51 people that found no difference in symptom likelihood between delaying this long and starting during an attack. Low dose colchicine (one study found 600 mcg bd to be helpful) or NSAID may be prescribed for up to six months, or until a stable dose is reached, to reduce the likelihood of an attack being precipitated.
When using allopurinol, start low and go slow. 100 mg is the usual starting dose, with 100 mg increments of increase. Increasing should be done monthly, following checks of FBC, E&C, LFTs, and urate. In people with renal failure, the starting dose should be lower and the upward titration slower; somewhat paradoxically, however, renal impairment is actually considered another indication for use of urate-lowering drugs (I’m guessing because of increased likelihood of attacks?) Other indications (apart from recurrent acute attacks as above) include:
- Radiographic damage
- Uric acid urolithiasis
90% of people have no problems on allopurinol. Potential problems include acute gout flare-up (if this happens, do not discontinue the allopurinol) and allopurinol hypersensitivity syndrome, a rare but life-threatening complication involving severe skin reaction and hepatic and renal dysfunction. This is less likely in patients who are initiated on a low dose, or who have good renal function or are not on diuretics.
(From ‘Clinical Review: Gout’, BMJ 2013; 347: f5648 doi: 10.1136/bmjf5648)