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Trial registered on ANZCTR

Registration number
Ethics application status
Not yet submitted
Date submitted
Date registered
Date last updated
Type of registration
Prospectively registered

Titles & IDs
Public title
Gout Treatment. Combined vs Allopurinol alone.
Scientific title
The effect of Probenecid-Allopurinol combined therapy compared to higher dose Allopurinol on serum uric acid levels in poorly controlled gout patients: A Pilot Prospective Study.
Secondary ID [1] 281194 0
Nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Gout 287375 0
Condition category
Condition code
Musculoskeletal 287708 287708 0 0
Other muscular and skeletal disorders
Inflammatory and Immune System 287724 287724 0 0
Other inflammatory or immune system disorders

Study type
Description of intervention(s) / exposure
The first group will have probenecid added into their usual daily allopurinol dose. (both agents licensed and frequently used in rheumatological practice). For the first 2 weeks, patients will receive low dose probenecid (500mg/24hrs) and allopurinol (300mg/24hrs) and these are increased after two weeks if well tolerated to 1000mg/24hrs probenecid plus the allopurinol (300mg) for the remaining 4weeks of the 6week trial. Both are oral tablets.
Intervention code [1] 285658 0
Treatment: Drugs
Comparator / control treatment
Second group will have their usual daily dose of allopurinol (300mg) increased. For the first 2 weeks patients will receive allopurinol 400mg once a day and if well tolerated this is increased to 600mg once a day (oral tablets) for the rest of the 6-week period.
Control group

Primary outcome [1] 287954 0
Comparison of serum uric acid levels
Timepoint [1] 287954 0
6 weeks
Secondary outcome [1] 299115 0
Frequency of gout attacks, measured by self-reported episodes in a 'flare-diary'
Timepoint [1] 299115 0
6 weeks
Secondary outcome [2] 299116 0
Patient-reported tolerance including other serious adverse events (death, life-threatening events, hospitalisation or event requiring medical intervention, disability causing significant persistent or permanent impairment, or disruption in daily functioning or quality of life as assessed by the patient's global health assessment)
Timepoint [2] 299116 0
2, 4, and 6 weeks
Secondary outcome [3] 299117 0
Renal function at the end of the 6week period, and if there has been a deterioration from pre-trial renal function (Comparison of pre-trial eGFR with end-of trial eGFR).
Timepoint [3] 299117 0
3 and 6 weeks

Key inclusion criteria
- Gout defined as per the American College of Rheumatology preliminary criteria. Any patient meeting this definition, either from a primary or secondary care source.
- Already receiving long-term maintenance therapy of allopurinol 300mg once a day for more than 1 month, yet still having uncontrolled SUA levels (defined as SUA>0.36).
- Consents to alteration in medications/doses
- Is able to take medications that are not confined to ‘blister packs’ – (pre-formed packs from pharmacist).
Minimum age
18 Years
Maximum age
90 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
- Known hypersensitivity to Probenecid, or higher dose Allopurinol
- Estimated glomerular filtration rate (eGFR) >60ml/min
- Known renal/ureteric stones
- Gout flare less than 2 weeks prior to entering the trial.

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Allocation is not concealed. Participants will be enrolled form rheumatology lists, GP lists, and local adverts.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Computerised randomisation once the full number of participants have been obtained.
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Other design features
Phase 4
Type of endpoint(s)
Statistical methods / analysis

Recruitment status
Not yet recruiting
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment outside Australia
Country [1] 4540 0
New Zealand
State/province [1] 4540 0
Bay of Plenty

Funding & Sponsors
Funding source category [1] 285976 0
Name [1] 285976 0
Tauranga Hospital
Address [1] 285976 0
Tauranga hospital, Cameron Road, Tauranga 3110, Bay of Plenty
Country [1] 285976 0
New Zealand
Primary sponsor type
Tauranga Hospital
Tauranga hospital, Cameron Road, Tauranga 3110, Bay of Plenty
New Zealand
Secondary sponsor category [1] 284796 0
Name [1] 284796 0
Address [1] 284796 0
Country [1] 284796 0

Ethics approval
Ethics application status
Not yet submitted
Ethics committee name [1] 288009 0
health and disability ethics committees
Ethics committee address [1] 288009 0
Ministry of Health
No 1 The Terrace
PO Box 5013
Wellington 6145
Ethics committee country [1] 288009 0
New Zealand
Date submitted for ethics approval [1] 288009 0
Approval date [1] 288009 0
Ethics approval number [1] 288009 0

Brief summary
We want to see which type of medication regime would best help patients with poorly controlled gout. One option is to increase the dose of their normal medication (Allopurinol 300mg) or to add in a second drug (Probenecid), with the aim being to compare the reduction in the level of uric acid (i.e. good response is where uric acid levels fall below 0.36, and this correlates well with better gout control), plus which regime is better tolerated by the patient. It is unblinded, therefore the participants will know which regime they are taking. They are assigned into the group taking Allopurinol 600mg (high dose-one drug group) or those taking 300mg with Probenecid (combined drug group). Patients will be followed up for 6weeks, with uric acid levels performed before, and after this 6week period.

- We hypothesise that higher doses of Allopurinol will more effectively control chronic gout (measured for this study as obtaining lower serum urate levels, but for patients this means fewer gout 'flares') compared to their pre-trial dose of Allopurinol (300mg).
- Our second hypothesis is that higher dose Allopurinol will be as well tolerated by individuals as their pre-trial dose of 300mg, with no significant deterioration in their kidney function.
- Thirdly, those regimes using a higher dose of Allopurinol will not be inferior to the addition of another agent, in this case Probenecid.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 34691 0
Address 34691 0
Country 34691 0
Phone 34691 0
Fax 34691 0
Email 34691 0
Contact person for public queries
Name 17938 0
Dr Christine Fox
Address 17938 0
Tauranga Hospital, Cameron Road, Tauranga 3110, Bay of Plenty
Country 17938 0
New Zealand
Phone 17938 0
(+64) 07 579 8000
Fax 17938 0
(+64) 07 578 2649
Email 17938 0
Contact person for scientific queries
Name 8866 0
Dr Tim Sole
Address 8866 0
Tauranga Hospital, Cameron Road, Tauranga 3110, Bay of Plenty
Country 8866 0
New Zealand
Phone 8866 0
(+64) 07 579 8000
Fax 8866 0
(+64) 07 578 2649
Email 8866 0

No information has been provided regarding IPD availability
Summary results
No Results