Abstract
6-Mercaptopurine (6-MP) has been used for the maintenance therapy of ALL in childhood. However its pharmacokinetics was not clarified because of the difficulties in measuring its plasma levels. Recently, the HPLC method for quantitation has been developed. Using this sensitive and specific method, we measured the plasma 6-MP levels in patients with ALL in complete remission.
The mean peak plasma level of 6-MP in 14 patients, administered 2 mg/kg orally, was 42.5 ng/ml with a mean time to the peak level of 1.64 hours. There was a 16.3 fold variation in the AUC (the area under the curve formed by plotting plasma concentration against time), in addition a 14.6 fold variation in peak plasma level among the patients.
This study suggests that plasma 6-MP levels should be monitered in its use. Especially, in patients with hepatic dysfunction, since plasma 6-MP was detectable so long, it is needed to moniter their plasma 6-MP levels as well as to decrease their dose.
