You should really join the yahoo liver shunt group.
Liver_Shunt_And_MVD_Support : Liver Shunt & MVD/HMD Support
They are VERY knowledgeable and will help you every step of they way. They can explain what each medicine is for and why the dog is taking it and if the vet gives you the wrong medicine they will know that too.
Good luck and hopefully Lilly will get better soon.