I do not  know if there is a software for it , however i think the degradation for every drug happens separately based on the existence of degradation factors.  .The comparison between degradation pathways,may show us if there is some synergistic effects of some degradation products.

You can construct the chemical model of  drug degradation and then carry out the simulation procedures with using the adequate  of QM/ MM  methods.

If these drugs are metal-based you can apply the DFT methodology, described in detail in papers: [Y. Zhang et al., J.Am. Chem. Soc 2001, 123, 9378], [Lau and Deubel, J. Chem Theory Comput. 2006, 2, 103-106], [C.W. Fong, Free Radical Biology and Medicine 95, 2016, 216.].