The merger of Raleigh’s Salix Pharmaceuticals with a subsidiary of Cosmo Pharmaceuticals largely boils down to two points: Tax savings and a deal involving a dug called Uceris.

On a conference call with analysts after Salix announced it would merge with Cosmo Technologies and move headquarters to Ireland, Salix CEO Carolyn Logan said that the move would effectively lower its long-term tax rate from the high 30-percent range to the low 20-percent range, and “will enable us to obtain lower tax…