This paper applies the isotopic field-charge spin theory (Darvas, IJTP 2011) to the electromagnetic interaction. First there is derived a modified Dirac equation in the presence of a velocity dependent gauge field and isotopic field charges (namely Coulomb and Lorentz type electric charges, as well as gravitational and inertial masses). This equation is compared with the classical Dirac equation. There is shown that, since the presence of isotopic fieldcharges would distort the Lorentz invariance of the equation, there is a transformation, which together with the Lorenz transformation restores the invariance of the equation, in accordance with the conservation of the isotopic field-charge spin (Darvas, 2009). The paper discusses the conclusions derived from the extensions of the Dirac equation. It is shown that in semiclassical approximation the model provides the original Dirac equation, and at significantly relativistic velocities it approaches to the Schrödinger equation. Among other conclusions, the clue gives physical meaning to the electric moment. The closing section summarises a few further conclusions and shows a few developments to be discussed in detail in a next paper (Darvas, 2013). A J J A J A what demonstrates an analogy with our formula derived in [22] based on the findings in this paper. Note also that the potential (Coulomb) charges behave like corpuscles, while the kinetic (Lorentz type) charges like waves [16]. This complementary double behaviour (formulated first by Bohr in 1927, then discussed in 1937 [5]) became subject of studies again (cf., [41]).