Symptomatic hypoglycemia in children receiving oral purine analogues for treatment of childhood acute lymphoblastic leukemia

Antimetabolite-based continuation therapy is commonly used for childhood acute lymphoblastic leukemia (ALL) and hypoglycemia after prolonged fasting has been recently reported. We have found that spontaneous, symptomatic hypoglycemia (SH) may also occur in such patients. Between 1995 and 1999, patients treated according to the AIEOP-ALL-95 study received BFM-type intensive chemotherapy; mercaptopurine (6-MP) was given (60 mg/m(2)/days, orally for 14 days) during the second part of induction and during consolidation therapy (25 mg/m(2)/day, orally for 8 weeks); thioguanine (6-TG) was given during reinduction therapy with protocol II (60 mg/m(2)/day, orally for 14 days); continuation therapy consisted of a combination of 6-MP (50 mg/m(2)/day orally) and methotrexate (MTX, 20 mg/m(2)/weekly, i.m.). We reviewed the charts of all patients treated for childhood ALL at our two centers. This was done to assess the incidence and the characteristics of all episodes of SH: sweating, pallor, nausea, abdominal pain with or without transient alterations of alertness, in the presence of blood glucose level of under 60 mg/dl. Six of 86 patients (6.9%) developed 18 episodes of SH. Five were male, none was older than 5 years, and four were only 3 years old. SH episodes occurred during consolidation (n = 2), reinduction (n = 7), and continuation (n = 9) phases. SH is a rare complication associated with administration of the purine analogues, mercaptopurine and thioguanine to children with reduced fat storage and young age.