Rheumatologists have proposed a framework for assessing allopurinol failure in patients with gout that offers practical advice on how clinicians should respond to various ‘failure’ scenarios to boost the chances of treatment success.
Allopurinol ‘failure’ is considered common in clinical practice, but only a very small number of people are unable to reach target serum urate when taking regular allopurinol at a sufficient dose.
As such, the New Zealand researchers Professor Lisa Stamp and Professor Nicola Dalbeth said that healthcare professionals should fully explore and address the potential reasons for persistently low urate levels or lack of clinical improvement in gout patients before deeming it to have failed.
“Understanding the causes of allopurinol ‘failure’ underpins the approach required to turn ‘failure’ into ‘success’ in gout management,” they stressed in their paper published in The Journal of Rheumatology [link here].
In the first instance, if target serum urate levels are not achieved while on allopurinol treatment, clinicians should ask where the drug is being sourced to rule out counterfeit products.
However, two of the most common drivers of treatment failure are “under-dosing and lack of regular prescribing by healthcare professionals,” the authors noted.
A key issue was that 300mg daily, which is widely considered a standard dose of allopurinol, is ineffective in achieving target serum urate in most patients.
This was demonstrated by the FACT trial, in which allopurinol was administered at a fixed dose of 300mg even with eGFR>50mls/min/1.73m2; results showed that only one-fifth (21%) attained a serum urate of <0.36mmol/L.
The authors stressed that allopurinol dose escalation beyond 300mg to the maximum approved dose to achieve target serum urate is safe and effective, even in gout patients with renal impairment.