We study theoretically the amodiaquine-adenine and amodiaquine-guanine adducts formation using Density Functional Theory (B3LYP) and the 6-31G(d) basis set for the geometry optimizations and 6-31+G(d,p) for the analysis of the global indexes: electrophilicity (w), electronic chemical potential (m), hardness (h) and softness (S), based in the Frontier Molecular Orbital Theory – FMO. Local softness for nucleophilic reaction (sk+) sites over guanine was evaluated using Fukui function (f k). We also evaluated the guanine Electrostatic Potential (EP) values using the (MSK) charge scheme. The theoretical calculations had demonstrated that the amodiaquine has greater electronic affinity for the guanine, with irreversible formation of the amodiaquine-guanine adduct, as reported before on a previous experimental work.