title: The effect of folate supplements on 6-mercaptopurine remission maintenance therapy in childhood leukaemia.
abstract: The effect of folic acid supplements on 6-mercaptopurine remission maintenance therapy in lymphoblastic leukaemia (ALL) was investigated in a retrospective longitudinal study of 10 children. Red cell concentrations of 6-thioguanine nucleotide, a cytotoxic metabolite of 6-mercaptopurine, were measured and the peripheral neutrophil count was used as an index of myelosuppression. During the control period of the study there were significant correlations between 6-mercaptopurine dose and 6-thioguanine nucleotide concentration (rs = 0.59, P less than 0.0005) and between 6-thioguanine nucleotide concentration and the peripheral neutrophil count at 14 days (rs = 0.58, P less than 0.0005). These relationships were absent when the same children were subsequently taking folate supplements. Also when taking folate supplements the children tolerated significantly more 6-mercaptopurine (P less than 0.005) for a significantly longer time (P less than 0.005) before neutropenia developed. There was no significant difference in red cell 6-thioguanine nucleotide concentration in the absence and presence of folate supplements. These findings suggest that folate supplements may interfere with remission maintenance therapy in ALL.
authors.forename: L
authors.initials: L
authors.lastname: Lennard
authors.forename: J S
authors.initials: JS
authors.lastname: Lilleyman
authors.forename: J L
authors.initials: JL
authors.lastname: Maddocks
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D004359:Drug Therapy, Combination; D005260:Female; D005492:Folic Acid / Q000627:therapeutic use*; D006801:Humans; D007945:Leukemia, Lymphoid / Q000097:blood / Q000150:complications / Q000188:drug therapy*; D007958:Leukocyte Count; D008297:Male; D015122:Mercaptopurine / Q000627:therapeutic use*; D009503:Neutropenia / Q000150:complications; D009504:Neutrophils; D013866:Thioguanine / Q000097:blood
chemical_list: D005492:Folic Acid; D015122:Mercaptopurine; D013866:Thioguanine