I fear I may have infected you with my tendency to overthink simple situations by analyzing what-if scenarios before they’ve happened.
I appreciate your concerns regarding cell breakdown from thalassemia. But, allopurinol has proved to be effective for uric acid reduction whatever the cause. Therefore, I think we should wait for blood test results.
Speaking of which, I have a standard view of the time between starting, or changing, allopurinol dose and retesting. 2 weeks is the minimum time to allow uric acid to stabilize. In my opinion, it’s best to go for 2 week intervals to get to the right allopurinol dose quickest. 4 weeks is common. Anything longer than 6 weeks indicates lack of effort.
Then, we move to interpreting the uric acid blood test results. I’m sorry for any confusion. But, 400 μmol/L is not a magic number. It’s the announcer, or magicians assistant, letting you know that magic is on it’s way.
In the lab, scientists have shown that uric acid crystals form at standard human body temperature when uric acid is 400 μmol/L. But, real life human uric acid tests are just a snapshot of an ever-changing environment. Take a test 4 hours later, and you’ll get a different result. When we account for the fact that joint temperatures are lower, the long term target is 300. That way, we can be sure uric acid is safe. Unless, exposure to prolonged low temperature is contributing to gout. In such cases, we can see that gout can occur at 268 μmol/L (4.5 mg/dL), if joint temperature is 30 centigrade (86 fahrenheit).
More importantly, during early uric acid lowering therapy, we get tremendous benefit from getting uric acid as low as possible. So, for me, the magic number would be your uric acid blood test result when you were on maximum allopurinol dose. Obviously (I hope), increased allopurinol doses should be monitored by blood tests every 2-4 weeks. Tests must be for kidney function and liver function, as well as uric acid.
Unfortunately, that type of maximum treatment can be difficult to sell to doctors. It depends on individual circumstances. But, at 300 μmol/L most gout sufferers will be safe.