Children with leukaemia experience difficulties adapting to medical procedures and to the chemotherapy’s adverse effects. Study’s objectives were to identify which coping strategies could be associated with the treatments’ factors and with the dosage of sedation analgesic drugs during bone marrow aspirates. 125 patients (M = 6.79 years; SD = 3.40), majority with acute lymphoblastic leukemia (90.4%) and their parents received, one month after diagnosis, the PPCI. Data on the severe treatment effects and on the dosage of drugs in sedation-analgesia were also collected. An ANCOVA model (R2=0.25) showed that, weighing the age factor (F=3.47; df=3; p=0.02), the number of episodes of fever (F=4.78; df=1; p=0.03), nausea (F=4.71; df=1; p=0.03) and mucositis (F=5.81; df=1; p=0.02) influenced the use of distraction. Cognitive self-instructions (R2=0.22) were influenced by the number of hospitalizations (F=5.14; df=1; p=0.03) and mucositis (F=8.48; df=3; p=0.004) and by child’s age (F=3.76; df=3; p=0.01). Children who sought parental support more frequently (F=9.7; df=2; p=0.0001) and who tended not to succumb to a catastrophic attitude (F=13.33; df=2; p=0.001) during the induction treatment phase required lower drug dosages, especially propofol. The clinical application of these results could be to encourage the use of cognitive self-instructions and search for social support.