My son’s endo says it is fine to take the whole Florinef dose at one time/once a day. Over the years we have sometimes divided it into 2 doses, sometimes had it in one.

However, we have noticed that when my son takes it in the morning only, he has a huge urine output at night. He is almost 5 and wears a night pull-up. When he takes 1/2 a dose at night he usually wakes up dry. When he takes the whole dose in the am he wets through the pull-up 5-6 times a week. His endo insists the florinef does not make a difference. I  would insist just the opposite. Most recently when he was wetting through every night and my husband and I were going crazy with 2 am sheet changes, I started dividing his dose again. From that night on, he has not wet through once! 

I understand your question isn’t about night wetting. Sorry to get on a tangent. I guess I just want to illustrate 2 thoughts (1) none of my son’s endos believe it matters if you divide it into two doses or not (2) for my son, I firmly believe he has better regulation when it is divided. But as others said, everyone is different in how they react to the meds.

I’ll also echo the comment about checking b.p. carefully. Whenever my son’s dose goes over .1 mg his b.p. shoots up really high.

Good luck.