Jen it could be that he needs to take the last dose later at night, as they say you should try to take it last thing at night ie 10 pm, and I would think earlier in the morning. Be very careful of dex as it can cause problems with stomach, skin, weight, and growth.  It is fine if the endo is used to using it!  Before trying this I would ask your endo to do a full 24 hour profile.  I agree with Anon when do you see the endo again?