We show how Schwitzer inequality allows us to find inequalities relating an additive descriptor of the form $D_p(G)=\sum _{i=1}^N{c}_i^p$ to its reciprocal $D_{-p}(G)=\sum _{i=1}^N{c}_i^{-p}$. We look at three cases (the inverse degree, the Kirchhoff, and the multiplicative degree-Kirchhoff indices) where $p=1$ and where, of the two $D_1(G)$ and $D_{-1}(G)$, one is known in closed form, therefore allowing to find an upper bounds for the other.