Uric acid lowering effect of oxipurinol sodium in hyperuricemic patients - therapeutic equivalence to allopurinol.
OBJECTIVE
Oxipurinol has been shown to be sufficiently absorbed after oral administration as a rapid release preparation of oxipurinol sodium. We compared the uric acid lowering affect of allopurinol and oxipurinol.


METHODS
In a multicenter, randomized, double blind crossover trial in 99 hyperuricemic patients with normal renal function we investigated the uric acid lowering effect of oxipurinol sodium (O) in daily amounts equimolar to 300 mg allopurinol (A). Mean pretreatment plasma uric acid concentrations in groups A/O and O/A were 8.3 +/- 1.4 and 8.7 + /- 1.4 mg/dl, respectively.


RESULTS
In group A/O the mean plasma uric acid decreased to 5.4 +/- 1.2 mg/dl with allopurinol treatment, and increased slightly to 5.7 + /- 1.3 mg/dl during the consecutive oxipurinol period. In group O/A plasma uric acid declined to 6.0 +/- 1.4 mg/dl with oxipurinol and was 5.6 + /- 1.3 mg/dl at the end of the allopurinol period. The overall average reduction compared to baseline was 3.0 mg/dl with allopurinol and 2.6 mg/dl with oxipurinol. The difference between the 2 treatments was small but significant (multiple p=0.027,2 tailed). The corresponding mean plasma oxipurinol concentrations were 9.24 mu g/dl at the end of the allopurinol period and 9.9 mu g/dl after treatment with oxipurinol (NS).


CONCLUSIONS
Oxipurinol is well absorbed and sufficiently effective in hyperuricemic patients when administered as a rapid release preparation of oxipurinol sodium. Oxipurinol sodium could be a substitute for allopurinol in hyperuricemic patients and possibly also with new uses for allopurinol.
Walter-Sack
I
I
Medizinische Klinik und Poliklinik, Abteilung Klinische Pharmakologie, Ruprecht-Karls-Universitat Heidelberg, Germany.
de Vries
J X
JX
Ernst
B
B
Frei
M
M
Kolb
S
S
Kosmowski
J
J
Priebe
U
U
Schroder
H E
HE
Slotty
C
C
Voss
A
A
Weber
A
A
Wegscheider
K
K
D000328:Adult; D000368:Aged; D000493:Allopurinol / Q000493:pharmacokinetics*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004791:Enzyme Inhibitors / Q000097:blood / Q000493:pharmacokinetics*; D006400:Hematocrit; D006801:Humans; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D010117:Oxypurinol / Q000097:blood / Q000493:pharmacokinetics*; D013810:Therapeutic Equivalency; D014527:Uric Acid / Q000097:blood*
D004791:Enzyme Inhibitors; D014527:Uric Acid; D000493:Allopurinol; D010117:Oxypurinol