This is a plain English summary of an original research article. The views expressed are those of the author(s) and reviewer(s) at the time of publication.
This large study, based on data from GP and hospital records, investigated the frequency of side effects with treatments given with allopurinol to prevent gout flares. It compared allopurinol combined with either colchicine or non-steroidal anti-inflammatory drugs (NSAIDs), with allopurinol alone.
The study found that:
- side effects were more common among people who took colchicine or NSAIDs alongside allopurinol than among those who took allopurinol alone
- diarrhoea was more likely with colchicine
- the risk of serious side effects was raised, but they remained uncommon, with colchicine or NSAIDs.
The findings provide reassurance about the low chance of serious side effects. They will inform shared decision making between clinicians and people with gout who are considering these medications.
For more information on gout, visit the NHS website.
The issue: how common are side effects of medications to prevent gout flares?
Gout is caused by high levels of urate, a waste product in the blood, which leads to severe pain and swelling in the joints, typically the big toe. More than 1 in 50 adults in the UK have the condition.
People who have had recurrent flares of gout, may be prescribed medicines such as allopurinol to lower their urate levels and prevent flares in the long-term. However, starting treatment can sometimes trigger a gout flare. To prevent this, doctors may prescribe colchicine or an NSAID (such as ibuprofen) alongside allopurinol for the first 6 months of treatment.
This study sought to clarify how often these drugs, which are considered to be safe, cause side effects when taken with allopurinol.
What’s new?
The researchers compared the GP and hospital records of 14,000 people with gout who started allopurinol alone with 14,000 people who took allopurinol and colchicine. In a similar but separate analysis, they compared 26,000 people who took allopurinol alone with 26,000 people who took allopurinol with NSAIDs. Comparisons were made for people of the same sex, a similar age, and with similar medical problems aside from gout.
As expected, people taking colchicine and NSAIDs had more side effects than people who did not. But overall, side effects were uncommon, especially severe side effects.
For every 100 people treated, each year those who combined allopurinol with colchicine:
- were twice as likely to have diarrhoea (8 people) as those who took allopurinol alone (3 - 4 people)
- had a slightly increased risk of heart attack (1 extra), neuropathy (1 extra), and muscle pain (less than 1 extra); risk of low white blood cells was raised marginally.
Again, considering 100 people treated, each year those who combined allopurinol with NSAIDs:
- were at greater risk of angina (4 – 5 people) than those who took allopurinol alone (3 – 4 people)
- had a slightly increased risk of heart attacks and kidney damage (less than 1 extra); risk of stomach ulcers was raised marginally.
Why is this important?
This study shows that, while there are some risks with taking colchicine or NSAIDs along with allopurinol, serious problems are uncommon. The results could inform discussions between doctors and patients considering these medications.
The National Institute for Health and Care Excellence Guidelines for gout recommend discussing the benefits and risks of medications to prevent gout flares when prescribing allopurinol. These findings could inform discussions.
The researchers caution that milder side effects may have been missed by this study; only those severe enough for someone to visit a GP would have been analysed.
What’s next?
Research within the same project explored which groups of people are at highest risk of colchicine side effects.
You may be interested to read
This is a summary of: Roddy E, and others. Safety of colchicine and NSAID prophylaxis when initiating urate-lowering therapy for gout: propensity score-matched cohort studies in the UK Clinical Practice Research Datalink. Annals of Rheumatic Disease 2023; 82: 1618 – 1625.
Easy-read information on gout from Health Talk and Versus Arthritis.
Guidelines on the management of gout from the British Society of Rheumatology.
Information on taking part in NIHR research on gout.
Funding: This study was funded by the NIHR Research for Patient Benefit programme.
Conflicts of Interest: None declared.
Disclaimer: Summaries on NIHR Evidence are not a substitute for professional medical advice. They provide information about research which is funded or supported by the NIHR. Please note that the views expressed are those of the author(s) and reviewer(s) at the time of publication. They do not necessarily reflect the views of the NHS, the NIHR or the Department of Health and Social Care.
