PHILADELPHIA — A new study confirms what rheumatologists already know: Some patients with gout fail to achieve adequate reductions in serum urate levels with recommended levels of allopurinol.
For these patients, increasing the dose of allopurinol above the recommended dose can lower serum urate to target levels, according to Dr. Lisa Stamp, who presented her results at the annual meeting of the American College of Rheumatology.
“The problem with the guidelines is that many patients fail to achieve target serum urate levels of less than 6 mg/dL, the critical level above which gout is more likely to occur. We are … commonly undertreating” the disease, said Dr. Stamp, a rheumatologist at the University of Otago, Dunedin, New Zealand.
Dr. Stamp and her colleagues enrolled 90 patients with gout who were on stable doses of allopurinol for at least 1 month (mean age, 58 years; 88% male). After the initial visit, 52 were found to have serum uric acid levels greater than 6 mg/dL. Of those, seven received lower-than-recommended allopurinol doses, as defined by the Hande criteria based on creatinine clearance.
Allopurinol dosage was increased above the recommended range for 45 patients in 50- to 100-mg increments per month until they reached target serum uric acid levels. Of 36 patients who completed the entire 12-month study period, 85% (31 patients) achieved serum uric acid levels less than or equal to 6 mg/dL at 12 months. No serious allopurinol-related adverse events were reported.
All dose increases of allopurinol above recommended guidelines significantly reduced serum uric acid. The percentage decrease in serum uric acid from baseline was 12.6% when 50 mg was added to the recommended dose, 20.8% when 100 mg was added, 25.9% with 150 mg 36.2% with 200 mg. 30% with 250 mg, and 35.6% with 300 mg. Some patients required dosage increases of up to 400 mg/day.
“My current recommendation is to first get the patient to the current recommended dose for at least 1 month before a dose increase. If that does not work, consider increasing the dose,” Dr. Stamp said.
Notably, five of the patients who were initially found to have serum uric acid levels greater than 6 mg/dL were actually found to have no detectable plasma oxypurinol, indicating noncompliance. “You have to keep reminding patients the disease will come back if they stop taking the allopurinol,” she added.
Dr. Stamp disclosed a relationship with Wyeth Pharmaceuticals.