We discuss a large class of phenomenological models incorporating quantum gravity motivated corrections to electrodynamics. The framework is that of electrodynamics in a birefringent and dispersive medium with non-local constitutive relations, which are considered up to second order in the inverse of the energy characterizing the quantum gravity scale. The energy-momentum tensor, Green functions and frequency dependent refraction indices are obtained, leading to departures from standard physics. The effective character of the theory is also emphasized by introducing a frequency cutoff . The analysis of its effects upon the standard notion of causality is performed, showing that in the radiation regime ( R 1) the expected corrections of the order (ω/ ) n get further suppressed by highly oscillating terms proportional to sin( R), cos( R), thus forbiding causality violations to show up in the corresponding observational effects.