The critical buckling load is:

MEd = 1.35 x (2 x 4^2 / 8) + 1.5 x (1.5 x 4^2 / 8) = 18.9 kNm

The beam requires additional shear reinforcement.

The design shear force is:

VEd = 1.35 x (2 x 4 / 2) + 1.5 x (1.5 x 4 / 2) = 18.5 kN

The provided reinforcement area is: