<qa>  What is the most effective regimen?The aim of the study is to determine the pharmacokinetic profile of sulfadoxine-pyrimethamine plus amodiaquine SPAQ when used for seasonal Intermittent Preventive Treatment IPT to prevent malaria in children aged 3 to 59 months in Lamarame, NDoffane District, Senegal. Several studies have shown that seasonal IPT in children can provide a high degree of protection against clinical malaria. SPAQ is the most effective regimen. However little is known about the pharmacokinetics of amodiaquine and sulfadoxine-pyrimethamine in children. The purpose of this study is to determine the pharmacokinetics profile of SPAQ when used for IPT in Senegalese children. 150 children aged 3 to 59 months will be enrolled in November. They will receive a therapeutic dose of sulfadoxine-pyrimethamine and amodiaquine, and will be followed up for 30 days. Four finger prick blood samples will be taken from each child for PK analysis. 