6mp (6-mercaptopurine) is the most important skeletal drug in the maintenance period. Since the blood concentration of 6MP cannot be directly measured nowadays, it is indirectly observed whether 6MP plays a role by detecting the degree of leukocyte or neutrophil suppression. Generally speaking, it is appropriate to maintain leukocyte count around 3.0×109/L or neutrophil count around 1.0-1.5×109/L, so as to achieve the purpose of treating leukemia without making the leukocyte suppression too low and prone to organismal infection.
(1) Neutrophil count > 1.0×109/L (i.e. 1000 cells/ml) should be taken as a regular dose.
(2) If the neutrophil count is < 1.0x109/L, but > 0.5×109/L, reduce the dosage. Please ask the doctor for the exact amount of reduction. However, myo-injected MTX can be used in the same amount as before.
(3) If the neutrophil count is < 0.5x109/L (i.e. 500 cells/ml), suspend 6MP and wait for ANC to rise, then use it again according to medical advice. Please ask your doctor whether to stop MTX at this time as well. Attention! When increasing the dosage, take it for at least 2-3 weeks and then further adjust according to the blood picture. Because of the effects of sheath injection, hormones and vincristine, the bone marrow will be suppressed to different degrees after sheath injection or vincristine pushing, and generally the blood picture will fall to the lowest level 2-3 weeks after sheath injection or vincristine pushing. (1) On the day of sheath injection or vincristine pushing (day 1): start taking hormone and use 6MP in the original amount (children in group 08 program 2 do not take 6MP); (2) The first week after sheath injection or vincristine pushing (day 8): at this time, the white blood cells and neutrophils will increase due to the effect of hormone (individual children have no obvious change). If the child responds well to the hormone and the white blood cells have doubled, take 6MP in the original amount, but do not increase the amount. Otherwise, the dosage of 6MP should be reduced, either by half or 1/3 of the original dosage, or by a large amount if the child is particularly sensitive. (3) For children in the 08 program group 2 (intermittent group), because the week of sheath injection or pushing vincristine does not take 6MP, but starts to use 6MP on the 8th day, so the reduction of 6MP can be less, such as reducing the usual dosage by about 1/3, such as the usual use of 1 tablet, can be reduced to 3/4 tablets; the usual use of 1/2 tablet, can be reduced to 1/3 tablets. However, it still needs to be determined according to the specific situation of your child. If the response to the hormone is good, you can also take the original amount. (4) Week 2 (day 15) after sheath injection or vincristine pushing: Most children’s blood picture will drop to the lowest at this time, but because the dose reduction of 6MP has been started in the previous week, it usually will not drop to the point that chemotherapy drugs cannot be used. Most children’s blood counts will start to rise from this week onwards, so they can return to their original dosage this week. However, some children’s blood counts will continue to drop until the third week (day 21) when they reach the lowest level, so they will need to continue to use the reduced amount of 6MP for another week and then return to the usual amount of 6MP the following week. (5) Week 3 (day 21) after sheath injection or vincristine pushing: the blood picture has basically recovered since this week, so you can take the original 6MP dosage. The administration of 6MP during the maintenance period is very critical to the treatment of leukemia. Although each child will adapt to 6MP differently, with 1-2 months of mapping and adjustment, we can find the most suitable 6MP usage for our children. Many of our veteran parents are basically proficient at making adjustments by the end of six months of maintenance.